Simple Interface Rev 5
Simple Interface Rev 5
TommyTommy N. N. Tyler Tyler 26 26 November November 20022002
1. REVISIONS
1. REVISIONS This version This version of the of the Simple interface is Simple interface is improved by improved by using 1K using 1K resistors instead of resistors instead of 10K for R1 10K for R1 and R2.and R2. The instructions have been completely rewritten to make the
The instructions have been completely rewritten to make them clearer and easier to follow. m clearer and easier to follow. The sections on Testing andThe sections on Testing and Troubleshooting now incorporate error messages used in the current version of IR.exe.
Troubleshooting now incorporate error messages used in the current version of IR.exe.
2.
2. GENERAL GENERAL DESCRIPTIONDESCRIPTION The Simple The Simple interface does interface does not use not use any IC's any IC's or other or other active devices, active devices, but insteadbut instead connects signal lines from the
connects signal lines from the PC's parallel port directly to the remote control. PC's parallel port directly to the remote control. It works with either 2-cell or 4-cellIt works with either 2-cell or 4-cell remotes, and is by far the easiest and least expensive interface to build.
remotes, and is by far the easiest and least expensive interface to build. The downside is that in a small percentage ofThe downside is that in a small percentage of cases there may be
cases there may be problems in performance ranging from minor annoyances to coproblems in performance ranging from minor annoyances to complete failure. mplete failure. Generally, theseGenerally, these problems are caused by an unfortunate combination of characteristics of the particular PC parallel port you are using problems are caused by an unfortunate combination of characteristics of the particular PC parallel port you are using and the model remote you
and the model remote you are testing. are testing. In most cases there are "work aroundIn most cases there are "work arounds" that enable satisfactory operation, ands" that enable satisfactory operation, and these are discussed in th
these are discussed in the sections on Testing and e sections on Testing and Troubleshooting. Troubleshooting. Batteries should be installed in the remote toBatteries should be installed in the remote to upload or download, even though the interface
upload or download, even though the interfacemay may pass the pass the Check InterfaceCheck Interface test of IR.exe without them. test of IR.exe without them.
3.
3. PARTS PARTS REQUIREDREQUIRED The following paThe following parts are all rts are all you need, you need, except for except for the cable the cable and 6-pin and 6-pin mating connector for mating connector for JP1.JP1.
ITEM
ITEM QTYQTY DESCRIPTIONDESCRIPTION
1.
1. 1 1 DB25 DB25 male male connectorconnector 2.
2. 1 1 DB25 DB25 connector connector hood, hood, any any size size or or shapeshape 3.
3. 2 2 Resistor, Resistor, 1K 1K 1/4W 1/4W (Radio (Radio Shack Shack 271-1321)271-1321) 4.
4. 1 1 Signal Signal diode, diode, 1N4148 1N4148 or or equivalent equivalent (Radio (Radio Shack Shack 276-1122)276-1122)
The part of an interface that always has been, and still is, the most difficult to obtain is the 6-pin female connector that The part of an interface that always has been, and still is, the most difficult to obtain is the 6-pin female connector that mates with JP1 in the
mates with JP1 in the remote. remote. To keep these instructions short and To keep these instructions short and focused on the rest of the focused on the rest of the project, they assume theproject, they assume the reader is using a
reader is using a flat ribbon cable with suitable connector. flat ribbon cable with suitable connector. Search the JP1 Group messages Search the JP1 Group messages and files for references toand files for references to connectors.
connectors. In particular, you In particular, you should download should download the filethe file6PinConnector.zip6PinConnector.zip from the from theFiles>Interface DesignsFiles>Interface Designs folder of folder of the JP1 Group.
the JP1 Group. It is strongly recommended that you It is strongly recommended that you make or buy this critical component as make or buy this critical component as the first step before startingthe first step before starting to build an interface.
to build an interface.
Figure
4. ASSEMBLY
4. ASSEMBLY Figure 1 Figure 1 shows how shows how the cable the cable and components and components are soldered are soldered to the to the DB25 connector, DB25 connector, along withalong with some details of suggested ways to pre-cut and form the component leads so the diode lead rests on the bodies of the some details of suggested ways to pre-cut and form the component leads so the diode lead rests on the bodies of the resistors and not their leads.
resistors and not their leads. The wire numbers refer to the pThe wire numbers refer to the pins of the JP1 connector they ins of the JP1 connector they are attached to. are attached to. Wires 1 andWires 1 and 2 of the cable are soldered to each other and nothing else.
2 of the cable are soldered to each other and nothing else. If you're using something other than a ribbon cable and IDCIf you're using something other than a ribbon cable and IDC connector you have the option of connecting these pins together back at the JP1 end, and using a 4-conductor cable, as connector you have the option of connecting these pins together back at the JP1 end, and using a 4-conductor cable, as shown in Figure 3.
shown in Figure 3. The diode is the only The diode is the only polarized component in the assembly, and polarized component in the assembly, and its banded endits banded endmust must be oriented be oriented
toward pin 2 as shown. toward pin 2 as shown.
In most computers pins 18 through 25 are all grounded inside the computer, and pin 3 of the JP1 connector must be In most computers pins 18 through 25 are all grounded inside the computer, and pin 3 of the JP1 connector must be connected to at least one of these grounded pins.
connected to at least one of these grounded pins. Figure 1 shows the connection being made to pin 25, which wasFigure 1 shows the connection being made to pin 25, which was selected arbitrarily.
selected arbitrarily. That wire might just That wire might just as well as well be soldered to be soldered to pin 24, or pin 24, or 23, etc. 23, etc. But occasionally we But occasionally we run across arun across a computer that does not have pin 25 grounded.
computer that does not have pin 25 grounded. How do you know, and what should you do about it?How do you know, and what should you do about it? You have at least three options.
You have at least three options. First, you can solder the wire to pin 25 as shown and not worry about it unless theFirst, you can solder the wire to pin 25 as shown and not worry about it unless the interface doesn't work.
interface doesn't work. The odds The odds are probably 99 are probably 99 to 1 yto 1 you won't have ou won't have a problem. a problem. Second, you Second, you can measure thecan measure the resistance from pin 25 to the
resistance from pin 25 to the chassis of your computer with an chassis of your computer with an ohmmeter. ohmmeter. It should be less than It should be less than one ohm. one ohm. If pin 25If pin 25 doesn't appear to be
doesn't appear to be grounded, find another pin in the group grounded, find another pin in the group from 18 to 25 that is gfrom 18 to 25 that is grounded, and use it. rounded, and use it. Third, justThird, just shotgun it by soldering a piece of wire to connect pins 18 through 25 as shown in Figure 2.
shotgun it by soldering a piece of wire to connect pins 18 through 25 as shown in Figure 2.
Figure
Figure 2. 2. View View of Cof Connector onnector Showing PiShowing Pins 18 ns 18 Through 25 Through 25 ConnectedConnected
When you have completed all soldering and double-checked everything for assembly errors, bad solder joints, shorts, When you have completed all soldering and double-checked everything for assembly errors, bad solder joints, shorts, etc., you can either go ahead and enclose the connector in its hood, or go to the section on Interface Testing and try it etc., you can either go ahead and enclose the connector in its hood, or go to the section on Interface Testing and try it first, depending on y
first, depending on your level of our level of confidence. confidence. Figure 3 shows Figure 3 shows the end pthe end product. roduct. The picture shows a The picture shows a ribbon cable withribbon cable with IDC (Insulation Displacement Connector) that was made by cutting a larger one to a 10-pin size and using the middle six IDC (Insulation Displacement Connector) that was made by cutting a larger one to a 10-pin size and using the middle six contacts, following the instructions in the download file
contacts, following the instructions in the download file 6PinConnector.zip6PinConnector.zip mentioned e mentioned earlier. arlier. It also It also shows the shows the optionoption of using a 6-pin connector with solder pins and a 4-conductor cable.
of using a 6-pin connector with solder pins and a 4-conductor cable. The type of cable you use is not critical, but don'tThe type of cable you use is not critical, but don't make it more than six feet long.
make it more than six feet long. Although not shown in Figure 3,
Although not shown in Figure 3, you must provide some form of you must provide some form of strain relief for the cstrain relief for the cable so the wires won't pull on table so the wires won't pull on theirheir connections during handling.
connections during handling. All hoods are All hoods are supplied with a supplied with a cable clamp of socable clamp of some sort. me sort. If you are If you are using a jacketed using a jacketed cablecable that's smaller than the clamp, wrap it with
that's smaller than the clamp, wrap it with a few layers of electrical tape so a few layers of electrical tape so the clamp holds securely. the clamp holds securely. When using aWhen using a ribbon cable the best way to provide strain relief is to reverse one of the cable clamps so the two nest with each other. ribbon cable the best way to provide strain relief is to reverse one of the cable clamps so the two nest with each other. But don't over-tighten the clamp or it may squeeze through the ribbon cable insulation over time and short out the wires. But don't over-tighten the clamp or it may squeeze through the ribbon cable insulation over time and short out the wires. Better yet, add some insulation material between the clamp and ribbon cable, such as a few layers of electrical tape. Better yet, add some insulation material between the clamp and ribbon cable, such as a few layers of electrical tape.
Figure
Figure 3. 3. Final Final Assembly Assembly of of InterfaceInterface
Most assembly errors are made at the JP1 connector end of the cable because it's so easy to get confused and Most assembly errors are made at the JP1 connector end of the cable because it's so easy to get confused and disoriented as to the numbering of the
disoriented as to the numbering of the pins. pins. Study Figure 3 carefully until you are sure Study Figure 3 carefully until you are sure your wires are connected to your wires are connected to thethe proper positions of JP1.
proper positions of JP1. If you do any If you do any continuity testing with a meter DO NOT stick anything larger continuity testing with a meter DO NOT stick anything larger than a 1/4 wattthan a 1/4 watt resistor lead into the connector or you may risk opening up the contact so that it no longer makes a reliable connection resistor lead into the connector or you may risk opening up the contact so that it no longer makes a reliable connection with the pin in the remote.
with the pin in the remote.
5. REMOTES
5. REMOTES WITHOUT 6-PIN CONNECTORSWITHOUT 6-PIN CONNECTORS If you If you are building are building this interface this interface and plan and plan to try to try and use and use it with it with aa remote without opening up the remote and installing a 6-pin connector in the empty holes, don't be surprised if you have remote without opening up the remote and installing a 6-pin connector in the empty holes, don't be surprised if you have a lot of problems.
a lot of problems. It is true that some members hIt is true that some members have inserted a 6-pin header into ave inserted a 6-pin header into their cable connector to convert it intotheir cable connector to convert it into a sort of male connector, and uploaded or downloaded while holding it against the remote's circuit board so that all six a sort of male connector, and uploaded or downloaded while holding it against the remote's circuit board so that all six pins make contact simultaneously.
pins make contact simultaneously. But this is a risky But this is a risky proposition because those holes are slightly laproposition because those holes are slightly larger than the pins,rger than the pins, with no resiliency to compensate
with no resiliency to compensate for slight misalignment. for slight misalignment. To make contact with all six To make contact with all six pins sometimes requires tediouspins sometimes requires tedious trial-and-error twisting and tilting of the connector, which can damage the
trial-and-error twisting and tilting of the connector, which can damage the holes over time. holes over time. Opening a remote isn't allOpening a remote isn't all that difficult if you follow the many instructions available, and if you are worried about damaging the circuit board maybe that difficult if you follow the many instructions available, and if you are worried about damaging the circuit board maybe you can find a friend who is more experienced with a soldering iron.
you can find a friend who is more experienced with a soldering iron.
6. TESTING
6. TESTING This section This section outlines a outlines a systematic sequence systematic sequence of tests yof tests you should ou should make before make before trying to trying to use a use a newly builtnewly built interface.
interface. Don't expect help Don't expect help from the Group from the Group unless you have unless you have followed all the suggestions followed all the suggestions here. here. Plug the interface intoPlug the interface into your computer and
your computer and connect the cable connect the cable to your remote. to your remote. (Be sure there (Be sure there are batteries in it.) are batteries in it.) Start IR.exe, click onStart IR.exe, click on
Configuration > Transmission Delay
Configuration > Transmission Delay, and set the value to, and set the value to 16001600. . Then Then click onclick onConfiguration > Set PortConfiguration > Set Port and set the and set the port address to the correct value.
port address to the correct value. If you are not sure what port address you're using you can just try the default addressIf you are not sure what port address you're using you can just try the default address 378 and if that fails come back and try address 278.
378 and if that fails come back and try address 278. You won't damage anything by using the wrong address, but ifYou won't damage anything by using the wrong address, but if there's another problem you may get an error message with both addresses.
out your owner's
out your owner's manual and learn manual and learn the correct address. the correct address. IfIfConfiguration > Auto CheckConfiguration > Auto Check is not checked, activate it by is not checked, activate it by clicking on it.
clicking on it. Click on
Click on Configuration > Check InterfaceConfiguration > Check Interface, and, andOKOK to start the test. to start the test. If you get a message that If you get a message that sayssaysThe remoteThe remote interface check succeeded
interface check succeeded, congratulations, you are done with , congratulations, you are done with testing. testing. Go directly to the section entitled Making aGo directly to the section entitled Making a Trial Download.
Trial Download. If you get an
If you get an error message instead, don't panic. error message instead, don't panic. The tests IR.exe makes when yThe tests IR.exe makes when you run theou run theCheck InterfaceCheck Interface test test consist of two steps.
consist of two steps. First, IR performs a basic test whose First, IR performs a basic test whose function is just to verify that there is function is just to verify that there is a live interface pluggeda live interface plugged into the PC at the specified parallel port.
into the PC at the specified parallel port. It does this by toggling the DØ output of the PC up and down a few times andIt does this by toggling the DØ output of the PC up and down a few times and making sure that signal loops through
making sure that signal loops through the interface and causes the S7 the interface and causes the S7 input of the PC to respond input of the PC to respond appropriately. appropriately. Only ifOnly if that test passes does IR proceed to a functional test to verify that there is actually a working remote connected to the that test passes does IR proceed to a functional test to verify that there is actually a working remote connected to the interface.
interface. It does this by sending It does this by sending an address byte to an address byte to the remote's EEPROM to see if it sends the remote's EEPROM to see if it sends back anback an acknowledgement.
acknowledgement.
There are two error messages associated with the basic test (
There are two error messages associated with the basic test (Always reading "1" from inverted input S7 . . .Always reading "1" from inverted input S7 . . . and and
Always reading "Ø" from inverted input S7 . . .
Always reading "Ø" from inverted input S7 . . . ) and either one can occur with or without the remote connected.) and either one can occur with or without the remote connected. There is one error message associated with the functional test (
There is one error message associated with the functional test (No response from remoteNo response from remote ). ). If you If you still get either still get either ofof the first two messages even after disconnecting the cable from your remote, you may as well leave it disconnected until the first two messages even after disconnecting the cable from your remote, you may as well leave it disconnected until you solve that problem.
you solve that problem. When you no longer receive either of thWhen you no longer receive either of those two error messages you wose two error messages you will receive aill receive aNo responseNo response
message, at which point you should reconnect the remote and continue testing. message, at which point you should reconnect the remote and continue testing.
There are a number of reasons you might receive any one of these error messages even when there's nothing wrong There are a number of reasons you might receive any one of these error messages even when there's nothing wrong with the interface you've built.
with the interface you've built. Probably 90 percent of all pProbably 90 percent of all problems are external to the interface itself, another 9 peroblems are external to the interface itself, another 9 percentrcent are related to the wiring of the 6-pin connector or the way it's plugged in, and only 1 percent involve the construction are related to the wiring of the 6-pin connector or the way it's plugged in, and only 1 percent involve the construction under the hood.
under the hood. For example, if there's nothing connected to For example, if there's nothing connected to the parallel port address you've selected in cothe parallel port address you've selected in config you'llnfig you'll get the
get the Always ØAlways Ø message. message. If you've selected a port address If you've selected a port address to which a printer or other peto which a printer or other peripheral is connected you'llripheral is connected you'll get either an
get either an Always ØAlways Ø or or Always 1Always 1 message, usually accompanied by a little note that says message, usually accompanied by a little note that says Also, an unexpectedAlso, an unexpected value ($XX) was encountered in the status register
value ($XX) was encountered in the status register . . If you plug the cable If you plug the cable into the remote upside down yinto the remote upside down you'll get theou'll get the
Always 1
Always 1 message. message. So the first thing to do So the first thing to do before looking for errors in the interface is to before looking for errors in the interface is to double check your setup double check your setup andand configuration settings and check for possible errors in the position or orientation of the JP1 connector in the remote. configuration settings and check for possible errors in the position or orientation of the JP1 connector in the remote. Except for the address, you don't have to worry about any other configuration parameters for your parallel port, such as Except for the address, you don't have to worry about any other configuration parameters for your parallel port, such as IRQ, or whether it is configured as
IRQ, or whether it is configured as an SPP, EPP, or ECP port. an SPP, EPP, or ECP port. IR.exe doesn't care about those IR.exe doesn't care about those things.things.
One good troubleshooting technique is to confirm positively that a given change causes a given effect by testing with One good troubleshooting technique is to confirm positively that a given change causes a given effect by testing with and without the change
and without the change several times. several times. As an example, suppose yAs an example, suppose you're getting a persistentou're getting a persistentAlways reading XAlways reading X error, so error, so you know you are not passing the basic test.
you know you are not passing the basic test. Following the above suggestion, you decide to disconnect the remote toFollowing the above suggestion, you decide to disconnect the remote to concentrate on this problem, and suddenly the failure mode changes to
concentrate on this problem, and suddenly the failure mode changes to No responseNo response, which means you, which means youhavehave passed passed the basic test!
the basic test! Good test procedure would be Good test procedure would be to try alternating with and without the remote connected several to try alternating with and without the remote connected several times, totimes, to make sure the failure pattern is
make sure the failure pattern is consistent. consistent. This example would suggest that This example would suggest that something occurs only when the remote issomething occurs only when the remote is plugged in that is preventing the interface from passing the basic test.
plugged in that is preventing the interface from passing the basic test. A possible cause might be that pins 3 and 4 ofA possible cause might be that pins 3 and 4 of the JP1 connector are swapped.
the JP1 connector are swapped. That would not interfere with passing the basic That would not interfere with passing the basic test with the remote disconnected, buttest with the remote disconnected, but pin 11 of the PC will be grounded any time the remote is connected, and the PC would interpret this as
pin 11 of the PC will be grounded any time the remote is connected, and the PC would interpret this asAlways readingAlways reading "1"
"1". . Although this example is not a veAlthough this example is not a very common occurrence, it illustrates the point that by ry common occurrence, it illustrates the point that by repeating the test severalrepeating the test several times and observing that the
times and observing that the Always reading "1"Always reading "1" error only occurs when we plug into the remote, our attention is error only occurs when we plug into the remote, our attention is focused on that connector.
focused on that connector. Even if you lack the technical skill to deduce exactly what the problem is, you at least haveEven if you lack the technical skill to deduce exactly what the problem is, you at least have an idea where to look.
an idea where to look. Confirmation like this also adds credibility to any Confirmation like this also adds credibility to any request for assistance made to the request for assistance made to the Group.Group.
7. TROUBLESHOOTING
7. TROUBLESHOOTING If yoIf you have u have followed the followed the Interface Test Interface Test instructions precisely instructions precisely but ybut you're still ou're still havinghaving problems, this section contains more detailed technical information that should get y
problems, this section contains more detailed technical information that should get you up and running. ou up and running. If the technicalIf the technical stuff makes your head
stuff makes your head spin just skim through it for possible ideaspin just skim through it for possible ideas. s. I'll start with some information that helps explain theI'll start with some information that helps explain the error messages a little more completely.
error messages a little more completely.
The DØ output (pin 2) is normally held high (near + 5 volts) by the PC, and momentarily driven low (near ground) from The DØ output (pin 2) is normally held high (near + 5 volts) by the PC, and momentarily driven low (near ground) from time to time when the PC is
time to time when the PC is sending out data. sending out data. High's are "1's" and High's are "1's" and low's are "Ø's". low's are "Ø's". The S7 input (pin 11) The S7 input (pin 11) is normallyis normally pulled up to + 5 volts by a resistor internal to the PC, but the input signal is inverted between the point where it enters pulled up to + 5 volts by a resistor internal to the PC, but the input signal is inverted between the point where it enters the PC at pin 11
the PC at pin 11 and the internal point where the PC actually and the internal point where the PC actually reads it. reads it. That's why the error messages refer to That's why the error messages refer to "inverted"inverted input S7".
reading the inverted S7 value as low.
reading the inverted S7 value as low. When the PC sends out data it makes pin 2 go low and high in a sequentialWhen the PC sends out data it makes pin 2 go low and high in a sequential pattern.
pattern. Each time pin 2 goes low it pulls pin 11 down toward ground through the diode, and when pin 2 returns high pinEach time pin 2 goes low it pulls pin 11 down toward ground through the diode, and when pin 2 returns high pin 11 returns high also.
11 returns high also. So when the output sequenSo when the output sequence at D0 is "1Ø1Ø" (high-low-high-low) the PC reads the ce at D0 is "1Ø1Ø" (high-low-high-low) the PC reads the inverted inputinverted input at S7 as just the opposite, "Ø1Ø1" (low-high-low-high).
at S7 as just the opposite, "Ø1Ø1" (low-high-low-high). When the error message says
When the error message says Always reading "Ø" from inverted input S7 even when Always reading "Ø" from inverted input S7 even when putting "Ø" on output DØputting "Ø" on output DØ it it means the PC thinks input pin 11 is stuck high because it can't make it go low by pulling it down with output pin 2. means the PC thinks input pin 11 is stuck high because it can't make it go low by pulling it down with output pin 2. TheThe reason might be that something is causing + 5 volts to be applied directly to pin 11, or it might be that the circuit from pin reason might be that something is causing + 5 volts to be applied directly to pin 11, or it might be that the circuit from pin 2 through the diode to pin 11 is not working properly.
2 through the diode to pin 11 is not working properly. When the error message says
When the error message says Always reading "1" from inverted input S7 even when putting "1" on Always reading "1" from inverted input S7 even when putting "1" on output DØoutput DØ it it means the PC thinks pin 11 is stuck low because when the PC makes output pin 2 high something else continues to means the PC thinks pin 11 is stuck low because when the PC makes output pin 2 high something else continues to hold pin 11 down.
hold pin 11 down. The reason might be that there is a short to ground somewhere in the wiring from pin 11 to pin 4 ofThe reason might be that there is a short to ground somewhere in the wiring from pin 11 to pin 4 of the JP1 connector.
the JP1 connector.
Hopefully, from the above discussion you can draw a few conclusions about the interface diode that connects pins 2 and Hopefully, from the above discussion you can draw a few conclusions about the interface diode that connects pins 2 and 11.
11. If the diode is open circuited or installed backwards the DØoutput will be unable to pull down the S7 input, and you'llIf the diode is open circuited or installed backwards the DØoutput will be unable to pull down the S7 input, and you'll get an
get an Always "Ø"Always "Ø" error. error. If the diode is shorted (the way If the diode is shorted (the way most diodes fail) you'll still be able to pamost diodes fail) you'll still be able to pass the basic test, butss the basic test, but you'll get a
you'll get aNo responseNo response failure when the remote tries to reply failure when the remote tries to reply to its address. to its address. However, if the error message saysHowever, if the error message says
Always "1"
Always "1" the diode can't be involved in the problem because there's no way it can be the cause of holding the S7 the diode can't be involved in the problem because there's no way it can be the cause of holding the S7 input low while the PC is keeping the DØ output high, even if it is shorted, reversed, or open.
input low while the PC is keeping the DØ output high, even if it is shorted, reversed, or open.
Fortunately, the interface has so few parts that finding an assembly error by visual inspection is usually not very difficult. Fortunately, the interface has so few parts that finding an assembly error by visual inspection is usually not very difficult. Tests requiring access to the internals of the interface while operating are easier to make if you use an extender cable to Tests requiring access to the internals of the interface while operating are easier to make if you use an extender cable to bring the interface out where you
bring the interface out where you can get to it. can get to it. Just be sureJust be surenot not to use a null modem cable as these have pins 2 and 3 to use a null modem cable as these have pins 2 and 3 swapped from one end to the other, and many don't even have connections to pins 11 and 25.
swapped from one end to the other, and many don't even have connections to pins 11 and 25. If you use an extenderIf you use an extender cable make absolutely sure it has continuity between pins 2, 3, 4, 11, and 25 from one end to the other.
cable make absolutely sure it has continuity between pins 2, 3, 4, 11, and 25 from one end to the other. None of theNone of the other pins matter.
other pins matter.
Your first task is to get to a point where you can pass the basic test with the remote disconnected, i.e., you no longer get Your first task is to get to a point where you can pass the basic test with the remote disconnected, i.e., you no longer get an
an Always reading "X"Always reading "X" error message. error message. It is important for you to understand It is important for you to understand that the only component in the that the only component in the interfaceinterface involved in passing the basic test is the diode (D1), because it's the only component in the signal path the PC uses to involved in passing the basic test is the diode (D1), because it's the only component in the signal path the PC uses to make the basic test.
make the basic test. It is not unheard of for It is not unheard of for mis-marked diodes to be sold at mis-marked diodes to be sold at bargain prices to disreputable suppliers.bargain prices to disreputable suppliers. For a persistent
For a persistentAlways reading "Ø"Always reading "Ø" error there is a simple way to determine if the diode is faulty, which is to run the error there is a simple way to determine if the diode is faulty, which is to run the
Check Interface
Check Interface test while shorting out the diode with a piece of wire or a paper clip. test while shorting out the diode with a piece of wire or a paper clip. If the basic test passes when theIf the basic test passes when the diode is shorted but fails when it is not, replace the diode.
diode is shorted but fails when it is not, replace the diode. If the test fails even when the diode is shorted theIf the test fails even when the diode is shorted the possibilities are narrowed considerably.
possibilities are narrowed considerably. Perhaps what you think are Perhaps what you think are pins 2 and 11 pins 2 and 11 of the DB25 connector are nof the DB25 connector are not reallyot really pins 2 and 11, or they are not making contact with the PC connector.
pins 2 and 11, or they are not making contact with the PC connector. As a last resort unplug the i
As a last resort unplug the interface from the PC, jumnterface from the PC, jum per pins 2 and 11 of the parallel per pins 2 and 11 of the parallel port connector with a beport connector with a bent papernt paper clip as shown in Figure 4, and run the
clip as shown in Figure 4, and run the Check InterfaceCheck Interface test. test. If you If you still get anstill get anAlways reading "X"Always reading "X" message instead of message instead of a
aNo responseNo response message there's a problem with your computer or the way your parallel port is setup. message there's a problem with your computer or the way your parallel port is setup.
Figure
Figure 4. 4. Jumper Jumper for for Loop-Back Loop-Back Test of Test of Parallel Parallel Port Port ConnectorConnector
When you get a
When you get a No responseNo response error message it means that the IR program can talk to the interface but is unable to error message it means that the IR program can talk to the interface but is unable to communicate with the
first make sure the connections from your ribbon cable (or whatever cable wires you are using) to the female pins in the first make sure the connections from your ribbon cable (or whatever cable wires you are using) to the female pins in the JP1 connector are intact.
JP1 connector are intact. You should check continuity You should check continuity between the end of each wire between the end of each wire inside the interface hood and itsinside the interface hood and its corresponding contact inside the JP1
corresponding contact inside the JP1 connector. connector. Always use the lead wire Always use the lead wire of a 1/4-watt resistor as a of a 1/4-watt resistor as a probe for insertingprobe for inserting into a JP1 contact, nothing larger.
into a JP1 contact, nothing larger. The odds are extremely small that
The odds are extremely small that the problem is in the remote itself, if it is the problem is in the remote itself, if it is otherwise working properly. otherwise working properly. That is, unlessThat is, unless you've installed the 6-pin connector yourself.
you've installed the 6-pin connector yourself. In that case you In that case you might double check your work might double check your work for shorts or poor solderfor shorts or poor solder joints.
joints. A common mistake is to use tA common mistake is to use too much heat when installing the connector, oo much heat when installing the connector, causing the plastic to soften causing the plastic to soften so thatso that the pins are crooked a
the pins are crooked and make poor contact. nd make poor contact. It's best to use a It's best to use a mating connector to hold the pins mating connector to hold the pins straight whilestraight while soldering.
soldering.
If you used ribbon cable and an IDC connector in your construction there are several traps you may have fallen into. If you used ribbon cable and an IDC connector in your construction there are several traps you may have fallen into. Since most ribbon cable wires aren't color-coded it's easy to get them mixed up or to swap wire 1 for wire 6.
Since most ribbon cable wires aren't color-coded it's easy to get them mixed up or to swap wire 1 for wire 6. And if theAnd if the cable isn't positioned carefully before squeezing the cover down, some of the tiny contact barbs can get bent over or cable isn't positioned carefully before squeezing the cover down, some of the tiny contact barbs can get bent over or miss the wires completely.
miss the wires completely. One of the subtlest mistakes can One of the subtlest mistakes can occur if you make your occur if you make your IDC connector by sawing off aIDC connector by sawing off a piece of a longer one.
piece of a longer one. Figure 5 shows the standard arrangement of wires and pins, using a 14-pin IDC connector as anFigure 5 shows the standard arrangement of wires and pins, using a 14-pin IDC connector as an
Figure
Figure 5. 5. Standard Standard Numbering Numbering of of IDC IDC Connector Connector PinsPins
example.
example. The left portion of the illustration shows an The left portion of the illustration shows an overhead view of the header overhead view of the header with its two rows of 1/40" squawith its two rows of 1/40" square pinsre pins spaced 1/10" in both directions, the mating connector with top removed so you can see the barbs that pierce the wire spaced 1/10" in both directions, the mating connector with top removed so you can see the barbs that pierce the wire insulation, and the ribbon cable.
insulation, and the ribbon cable. All IDC connectors have an eAll IDC connectors have an even number of pins, with the barbs ven number of pins, with the barbs staggered as shownstaggered as shown because the wires are
because the wires are spaced every 1/20" apart. spaced every 1/20" apart. The actual parts are not marked with The actual parts are not marked with pin numbers, and the connectorpin numbers, and the connector can be reversed end
can be reversed end for end without changing anything. for end without changing anything. The pin numbers in Figure 5 The pin numbers in Figure 5 show the most commonshow the most common
convention, which is that when holding the connector over the header with the ribbon cable exiting toward you, pin 1 of convention, which is that when holding the connector over the header with the ribbon cable exiting toward you, pin 1 of the header is the near left corner one, and the wire on the left is number 1.
the header is the near left corner one, and the wire on the left is number 1. That's the way the pins of the JP1 headerThat's the way the pins of the JP1 header are arranged.
are arranged. Some IDC connectors have a Some IDC connectors have a strain relief that loops the cable back over strain relief that loops the cable back over the top of the connector athe top of the connector andnd clamps it there
clamps it there with a piece with a piece of plastic. of plastic. This obviously reverses This obviously reverses the direction rule. the direction rule. Find pin 1 Find pin 1 of your connector aof your connector and marknd mark that corner with a drop of fingernail polish.
that corner with a drop of fingernail polish.
When you cut a longer connector to make a shorter one, in order for wire number 1 to make contact with pin number 1 When you cut a longer connector to make a shorter one, in order for wire number 1 to make contact with pin number 1 you should always try to leave one end uncut and cut the other end
you should always try to leave one end uncut and cut the other end so as to have an even number of sockets. so as to have an even number of sockets. You'llYou'll actually cut through one of the wire piercing barbs when you do this, which is why it's recommended you use a 10-pin actually cut through one of the wire piercing barbs when you do this, which is why it's recommended you use a 10-pin housing with the outer barbs re
housing with the outer barbs removed for a 6-pin connector. moved for a 6-pin connector. This also makes the connector wide This also makes the connector wide enough that you can'tenough that you can't inadvertently plug it in
inadvertently plug it in off center. off center. If you somehow If you somehow wind up wind up cutting both ends bcutting both ends be careful. e careful. Figure 5 shows Figure 5 shows a 6-pina 6-pin connector made wrongly by cutting a very long connector between pins 11 and 12, and between pins 21 and 22. connector made wrongly by cutting a very long connector between pins 11 and 12, and between pins 21 and 22. ItIt
"starts on the wrong foot" so to speak, and there's no way it can be made to work.
"starts on the wrong foot" so to speak, and there's no way it can be made to work. And you can't fix the mistake byAnd you can't fix the mistake by turning the connector around and
turning the connector around and re-assembling it to the cable. re-assembling it to the cable. That connector is scrap.That connector is scrap.
8.
8. MAKING MAKING A A TRIAL TRIAL DOWNLOADDOWNLOAD Once Once you you can can pass pass thethe Check InterfaceCheck Interface test you're ready for a trial download. test you're ready for a trial download. Even if you can't pass the test you won't hurt anything if you try a download, but you will undoubtedly just get the same Even if you can't pass the test you won't hurt anything if you try a download, but you will undoubtedly just get the same error message since IR will make the same tests if the
error message since IR will make the same tests if theAuto CheckAuto Check feature is feature is check marked. check marked. The Auto The Auto Check optionCheck option causes IR to make the interface tests automatically at the start of every upload or download, as a means of continually causes IR to make the interface tests automatically at the start of every upload or download, as a means of continually monitoring the proper functioning of the interface.
monitoring the proper functioning of the interface. It is activated or deactivated by clicking onIt is activated or deactivated by clicking onConfiguration > AutoConfiguration > Auto Check
Check, and I recommend that you leave it activated except when experimenting to see if you can download without, and I recommend that you leave it activated except when experimenting to see if you can download without passing the interface test.
passing the interface test.
It doesn't really make any difference which page of IR is displayed while you are downloading, and they are all blank It doesn't really make any difference which page of IR is displayed while you are downloading, and they are all blank anyway.
anyway. Click Click ononRemote > Download from RemoteRemote > Download from Remote. . That should bThat should bring up a vring up a very important confirmation messageery important confirmation message that says
that says Ready to download from remoteReady to download from remote..
Click on
Click on OKOK to start the download. to start the download. If all goes well you will see If all goes well you will see the default namethe default name Remote Control Programmer Remote Control Programmer in the in the title bar replaced with the name of your remote (e.g.,
title bar replaced with the name of your remote (e.g.,URC7200 Cinema 7URC7200 Cinema 7) and in a second or two the small red dot in) and in a second or two the small red dot in the lower left corner of the window will blink twice to signal the completion of download.
the lower left corner of the window will blink twice to signal the completion of download. If you get a message that says
If you get a message that says No definition file exists for this remote. . . .No definition file exists for this remote. . . . it usually means it usually means there is no there is no RDF (RemoteRDF (Remote Definition File) for your model
Definition File) for your model remote in the directory with remote in the directory with IR.exe. IR.exe. Don't worry about Don't worry about that right now. that right now. When you click onWhen you click on
Yes
Yes you should still receive a you should still receive a download of the uninterpreted raw data. download of the uninterpreted raw data. You just won't be aYou just won't be able to do any programmingble to do any programming until IR can identify your remote.
until IR can identify your remote. When you download IR.exe it comes buWhen you download IR.exe it comes bundled with RDF files for all the ndled with RDF files for all the model remotesmodel remotes IR supports.
IR supports. So the first thing to try is So the first thing to try is downloading the latest revision of IR.exe. downloading the latest revision of IR.exe. If the RDF file is not in there yIf the RDF file is not in there you'll haveou'll have to ask for help from the Group
to ask for help from the Group Click on the
Click on theRaw DataRaw Data tab to view the tab to view the EEPROM contents. EEPROM contents. If the data is all "If the data is all "FFFF"s or all ""s or all "ØØØØ"s the problem may be"s the problem may be something other than a missing R
something other than a missing RDF. DF. Sometimes the only way to rectify this problem is Sometimes the only way to rectify this problem is to do a full to do a full manual reset of themanual reset of the remote (
remote (Code 981Code 981) and try another download. ) and try another download. Unfortunately, the reset will cause all programming in the remote to beUnfortunately, the reset will cause all programming in the remote to be erased.
erased.
Sometimes an interface will pass the
Sometimes an interface will pass the Check InterfaceCheck Interface test completely but give a test completely but give aNo responseNo response error message when you error message when you try to
try to download. download. The most The most likely cause likely cause is incompatibility between yis incompatibility between your PC our PC and remote. and remote. Unfortunately, theUnfortunately, the
incompatibility problem is partially dependant on the characteristics of the specific EEPROM in the remote, which is one incompatibility problem is partially dependant on the characteristics of the specific EEPROM in the remote, which is one reason why another person building the
reason why another person building the same interface for the same remote might get same interface for the same remote might get different results than you do. different results than you do. IfIf you have another remote you can try, it may behave differently.
you have another remote you can try, it may behave differently. Make sure you are not running the interface any faster than a
Make sure you are not running the interface any faster than a Transmission DelayTransmission Delay setting of setting of16001600. . To make To make sure sure thethe response time of your computer and cable is not a problem; try setting the
response time of your computer and cable is not a problem; try setting theTransmission DelayTransmission Delay to a ridiculous value, to a ridiculous value, such as
such as 1600016000. . That's running in super slow motion (download That's running in super slow motion (download of a 1K EEPROM will take about of a 1K EEPROM will take about 12 seconds) so unless12 seconds) so unless you get a miraculous cure set it back to
you get a miraculous cure set it back to 16001600. . In case you are interested, the In case you are interested, the speed reduction factor is equal to thespeed reduction factor is equal to the
Transmission Delay
Transmission Delay setting divided setting divided by 100, plus by 100, plus 1. 1. So a So a setting ofsetting of16001600 is running the program 17 times slower than it is running the program 17 times slower than it runs at its maximum speed with a setting of zero.
runs at its maximum speed with a setting of zero.
The most common incompatibility problem is that the PC
The most common incompatibility problem is that the PC is operating at one voltage and is operating at one voltage and the remote at another. the remote at another. ForFor example, if a 2-cell remote with old batteries is operating at 2 volts, the PC's DØ output might not be able to pull the SDA example, if a 2-cell remote with old batteries is operating at 2 volts, the PC's DØ output might not be able to pull the SDA line quite low enough through diode D1 to qualify as a "Ø".
line quite low enough through diode D1 to qualify as a "Ø". This situation can be improved by using a Shottky typeThis situation can be improved by using a Shottky type diode such as the BAT83 or 1N5818, which has a forward voltage drop a few tenths less than an ordinary diode.
diode such as the BAT83 or 1N5818, which has a forward voltage drop a few tenths less than an ordinary diode. ThoseThose are inexpensive components, but they're not available from Radio Shack, and must be obtained from an electronic parts are inexpensive components, but they're not available from Radio Shack, and must be obtained from an electronic parts supplier such as Mouser, Digi-Key, or
supplier such as Mouser, Digi-Key, or Jameco Electronics. Jameco Electronics. You might also be You might also be able to reduce the voltage mis-match justable to reduce the voltage mis-match just enough to cure the problem by installing fresh batteries in the remote.
enough to cure the problem by installing fresh batteries in the remote.
CAUTION:
CAUTION: If you see a longer message that saysIf you see a longer message that says Ready to uReady to upload to remote. pload to remote. This willThis will completely overwrite the programming currently in
completely overwrite the programming currently in the remotethe remote, you have clicked on, you have clicked on
Upload
Upload by mistake, and you should click on the by mistake, and you should click on the CancelCancelbutton immediately. button immediately. Never, Never, everever upload any data to any remote until you have first downloaded and saved its present data upload any data to any remote until you have first downloaded and saved its present data
so that you can restore the original programming if necessary. so that you can restore the original programming if necessary.
The opposite situation occurs when trying to download a 4-cell remote operating at about 6 volts with a laptop PC that The opposite situation occurs when trying to download a 4-cell remote operating at about 6 volts with a laptop PC that has an output voltage of 3.5 volts or less, because the PC's D1 output might not be able to pull the SCL line quite high has an output voltage of 3.5 volts or less, because the PC's D1 output might not be able to pull the SCL line quite high enough through resistor
enough through resistor R1 to qualify R1 to qualify as a "1". as a "1". Here the problem is Here the problem is made worse with made worse with fresh batteries. fresh batteries. A possible solutionA possible solution is to use worn-out batteries, or operate the remote on only three of its four cells, as explained in the section on
is to use worn-out batteries, or operate the remote on only three of its four cells, as explained in the section on Permanent Reset.
Permanent Reset.
There are many error messages that can occur during a download that relate to the content of the download (Header There are many error messages that can occur during a download that relate to the content of the download (Header read failure, Checksum error, etc.) but those are b
read failure, Checksum error, etc.) but those are beyond the scope of these eyond the scope of these instructions. instructions. This project concludes whenThis project concludes when you have a working interface.
you have a working interface.
9. PERMANENT RESET
9. PERMANENT RESET Sometimes a Sometimes a remote will remote will remain permanently remain permanently reset as reset as long as long as it is it is connected to connected to thethe interface.
interface. The symptoms of The symptoms of this are: this are: (1) You can't (1) You can't operate the remote operate the remote while it is while it is connected. connected. (2) The (2) The remote's red LEDremote's red LED doesn't blink twice following
doesn't blink twice followingCheck InterfaceCheck Interface,,UploadUpload, or, orDownloadDownload. . (3) The red (3) The red LED blinks twice wLED blinks twice whenever thehenever the remote is disconnected.
remote is disconnected. There are two There are two causes for this pcauses for this problem. roblem. One is the One is the voltage mis-match situation discussedvoltage mis-match situation discussed previously.
previously. If you are working with a If you are working with a 6-volt remote with fresh batteries, and your PC's output 6-volt remote with fresh batteries, and your PC's output voltage is not high enoughvoltage is not high enough to release the reset signal on the remote's processor, the processor will remain reset as long as the remote is
to release the reset signal on the remote's processor, the processor will remain reset as long as the remote is connected.
connected. The important thing to remember is that this shortcoming does nThe important thing to remember is that this shortcoming does not prevent you from using the inot prevent you from using the interface toterface to upload or download because
upload or download because the processor must be held the processor must be held reset during those operations anyway. reset during those operations anyway. It simply means theIt simply means the JP1 connector must be unplugged before the remote can be operated, something most people do routinely.
JP1 connector must be unplugged before the remote can be operated, something most people do routinely.
The reduction of resistor R2 in this Rev 5 version of the interface should greatly reduce the incidence of permanent The reduction of resistor R2 in this Rev 5 version of the interface should greatly reduce the incidence of permanent reset, but there is not enough
reset, but there is not enough evidence yet to confirm this, particularly when used evidence yet to confirm this, particularly when used with laptop PC's. with laptop PC's. If you absolutelyIf you absolutely must be able to operate the remote while it is still connected to the interface you can try reducing the operating voltage must be able to operate the remote while it is still connected to the interface you can try reducing the operating voltage of a 4-cell remote to 4.5 volts by replacing one cell with a dead battery or a dummy.
of a 4-cell remote to 4.5 volts by replacing one cell with a dead battery or a dummy. This will result in some reduction inThis will result in some reduction in maximum operating distance, so it may no
maximum operating distance, so it may not be a totally satisfactory solution. t be a totally satisfactory solution. You can make a You can make a dummy AAA size batterydummy AAA size battery by cutting a 1-3/4 inch length of 3/8 inch diameter wooden dowel rod and wrapping it with aluminum foil or aluminum by cutting a 1-3/4 inch length of 3/8 inch diameter wooden dowel rod and wrapping it with aluminum foil or aluminum (not cloth) duct tape.
(not cloth) duct tape.
10.
10. SCHEMATIC SCHEMATIC AND AND THEORY THEORY OF OF OPERATIONOPERATION As shown As shown in Figure in Figure 6, the 6, the RESET line RESET line is controlled is controlled directly by directly by thethe D2 output of the parallel port through resistor R2, which limits current into the reset pin in case the remote is operating at D2 output of the parallel port through resistor R2, which limits current into the reset pin in case the remote is operating at a lower voltage than the
a lower voltage than the computer. computer. The SCL line is The SCL line is controlled by the D1 output through controlled by the D1 output through resistor R1. resistor R1. The PC can sendThe PC can send clock signals through R1 to the EEPROM while the remote is reset, and the remote can send clock signals to the clock signals through R1 to the EEPROM while the remote is reset, and the remote can send clock signals to the EEPROM while the PC is holding D1 high and R1 acts as a pull-up.
EEPROM while the PC is holding D1 high and R1 acts as a pull-up. The SDA line is controlled by the DØ outputThe SDA line is controlled by the DØ output through the diode.
through the diode. When DØ is high When DØ is high the diode is the diode is reverse biased. reverse biased. Under this condition the Under this condition the processor can send processor can send andand receive data to the EEPROM on the SDA line, and the EEPROM can send data to the PC on the S7 line.
receive data to the EEPROM on the SDA line, and the EEPROM can send data to the PC on the S7 line. When theWhen the processor output is in tri-state, a low on DØ will pull down on the SDA line through the diode, and a high will let R19 pull processor output is in tri-state, a low on DØ will pull down on the SDA line through the diode, and a high will let R19 pull up on it.
up on it. That's the way the PC That's the way the PC sends data to the EEPROM.sends data to the EEPROM.
Figure
