Problem with self-modified URC-6131

[Biff]

Hi,
I have a URC-6131 and an "Ultra" kit from here: http://jp1.filebug.com/kits.htm

I also ordered the 2k eeprom along with the cable kit.

I have installed the eeprom and the 6 pin header, and then built the cable
as per the excellent instructions.

The eeprom seems to be installed properly - since this test works fine:

a) press and hold SET, two flashes
b) type 981, four flashes

I also tried this test on a non-modified URC-6131 to verify that there was indeed a different result - and on the non-modified one I get 2 short blinks
and 1 long blink.

There is no dimple on the eeprom that I can see - nor any other indicator as to which end pin 1 is on.
I installed it assuming that the when the text on the eeprom is right side up - pin one is to the upper left.

I'm assuming that since it passed the 9-8-1 test I have the eeprom soldered in properly.



Now - the problem:
I am unable to download from the remote when using ir.exe.

I have verified that the printer port setting is configured to match the port address of my desktop machine.

With the cable plugged into my remote (with batteries) the "Check Interface..." option always fails.

I have tried the cable on two other machines (notebooks) after selecting the proper port number.

In each case, immediately after receiving the "No response from interface..." error - the LED on my remote blinks twice.


I have reflowed the solder on my 6 pin header - and verified I wired the cable properly according to the instructions here:
http://jp1.filebug.com/files/UltraAssembly.doc

I have tried with and w/out the batteries in the remote - both times it fails while checking the interface, but I only received the 2 blinks immediately afterwards when the batteries are installed.

I was hoping that those two blinks may be a sign I only have something minor wrong.....

[The Robman]

What is printed on the top of the EEPROM chip? I ask because there are some chips floating around, supplied by Jameco, that are the wrong chip.

I know that Tom (Filebug) gets his chips from Jameco, as do I, and if you got the correct chip, you are correct that there isn't a dimple to indicate pin1. I discovered that the small logo on the chip can be used to indicate pin1, so check the chip is the right way around.

[Biff]

Ok - they say a picture is worth a thousand words....



Yeah - I now see also that it is on a bit crooked - but I believe all pins
are actually making contact.

I'll have to try re-soldering it using a desk magnifying glass or something.

But - I just want to make sure I have it in the right direction at least....

Jim

[The Robman]

"24C16" is the right part number. The logo under the "24" is what I use to indicate pin1.

I would take a closer look at pins 5 thru 8 as all of them look like they could potentially be not making contact.

When I solder these chips in, I hold the chip in place with a pair of tweezers, then I lay the tip of my iron across pins 1 thru 4. These then serve to hold the chip in place while I solder pins 5 thru 8 individually.

Remember that it doesn't matter if the solder bleeds betweens pins 1 thru 4 as the PCB trace ties them all together anyway.

[Biff]

"24C16" is the right part number. The logo under the "24" is what I use to indicate pin1.

I would take a closer look at pins 5 thru 8 as all of them look like they could potentially be not making contact.

Yeah, I know - it was a poor soldering job in poor lighting.

I took it to one of the labs here at work with proper soldering stations - removed the chip (gobbed solder on both sides so it slid right off the board)
and then after cleaning up the chip and pads - I used a magnifying glass and tweezers to properly position it.

End result - well, it looks much better now, but I still only get an error - and two blinks from the LED.

*sigh*

[zaphod7501]

An awfull lot of STmicroelectronics' chips are 5.5 volt. Might work great in a 8810 but the 6131 is a 3 volt remote. Try with very fresh batteries (or no batteries). I got my first 6131 to work with a 5.5 volt chip but the first big order to Mouser I watched the ratings on the parts I bought just for the voltage issue and replaced the test remote's IC as soon as possible.

Just some guesses from a distance.

[Biff]

An awfull lot of STmicroelectronics' chips are 5.5 volt. Might work great in a 8810 but the 6131 is a 3 volt remote. Try with very fresh batteries (or no batteries). I got my first 6131 to work with a 5.5 volt chip but the first big order to Mouser I watched the ratings on the parts I bought just for the voltage issue and replaced the test remote's IC as soon as possible.

Just some guesses from a distance.

I see Jameco is selling the chip also, their page says it is a 2-5v part.
I assume this would be the same flavor as the chip from Mouser?

http://www.jameco.com/webapp/wcs/stores ... tId=135705

New batteries did not make a difference, and with no batteries - I do not even get the "2 flashes" after the error prompt.

Jim

[mtakahar]

I see Jameco is selling the chip also, their page says it is a 2-5v part.
I assume this would be the same flavor as the chip from Mouser?

http://www.jameco.com/webapp/wcs/stores ... tId=135705

According to the datasheet:

Code: Select all

n Single Supply Voltage:
– 4.5V to 5.5V for M24Cxx
– 2.5V to 5.5V for M24Cxx-W
– 1.8V to 3.6V for M24Cxx-R

I can't see 'W' or 'R' marking in your photo image. Are you sure yours is not M24Cxx?


Hal

[jherrick]

Just an FYI for those who don't know, Pin 1 is always marked in some manner, and in this case it is the entire side. If you look at the bevel on the side of the chip, the bevel on the side of pin 1 is larger than that on the other side. It can be difficult to see.

Sometimes it's a dimple right by the pin, sometimes it's a semicircle on the end that pin 1 is on, but there is something and it's almost never the printing. In many cases they get the little emblem on the right corner, but in some that can be misleading.

Biff,
How many times did you try to reflow this part? With all the cleaning and "hitting" the pins with the iron are you sure that you didn't lift a pad? They are only glued to the boards, and if you used too much heat or "hit" it too many times it could be a bad connection. Or you could have damaged the chip. Did you get two when you ordered them? If so, try the other one.
Jim

[Biff]

How many times did you try to reflow this part?

I removed it once - and resoldered it back down.

With all the cleaning and "hitting" the pins with the iron are you sure that you didn't lift a pad?

I'm positive - I did not pry the chip off the pads nor pick it off - while keeping all 8 pins under a gob of solder - it slid right off the pads.
I also did not keep the gob on any longer than necessary - no chance of burning a hole thru the pcb

Or you could have damaged the chip. Did you get two when you ordered them? If so, try the other one.

It is possible I could have damaged it I guess, but I really doubt it, since
this remote acts as expected when holding down set for two blinks, then pressing "9-8-1" (4 resulting blinks) as opposed to doing the same thing on one of my unmodified URC-6131's - which result in 2 short blinks and
one 1 long one.

Here's what it looks like now:



From what I have read, I am supposed to see two blinks when IR.exe is uploading data from the remote - and I DO see two blinks, but unfortunately, only after IR.exe tells me there is a problem.

It is almost like there is a timing issue....

Jim

[jherrick]

Biff,
Without knowing if it is the remote or the interface, this becomes shooting in the dark. Do you have another jp1 ready remote? If not, do you have a Radio Shack or Circuit City or anything nearby where you could get one and return it without penalty, just to see if it is the interface?
Jim

[jherrick]

So this weekend I got two EEPROM chips from Mouser. I got the 2K 24LC024 model, Mouser part number 579-24LC024-I/SN. I put it on a 6131 board I am doing for someone and tried the 981. Didn't work. Two short and one long flash. I checked my solder joints, checked for Vcc to the correct pin, everything was good.

I then took an old 15-2107 I had lying around (clearance for 7 bucks a year or two ago) and put that chip on the 6131 board. It was a 16K, but it took the 981 immediately. The only difference I could see was the part numbers, manufacturers, and sizes. The 2K was 24LC024 from Microchip, and the 16K was 24WC16 from CSI (Catalyst Semi).

I looked at the manufacturers data sheets to see if I could find anything that shot out at me, but couldn't find anything. Does anyone know from looking at these data sheets if there is an appreciable difference?

Jim

[The Robman]

Your "2k" chip is 2k bits, when we talk about a 2k chip, we're talking about 2k of BYTES, which is 16k of bits.

The 2 digits after the letters are the chip's size in BITS, so the chip you're looking for will have a part number similar to 24C16 (like the 24WC16 you got from the 15-2107). Your chip has part number 24LC024 which is 02k bits.

[jherrick]

Wow. With everything else on my mind lately I completely let that one slip. I guess that explains that. Good thing I was including them in another order anyway, and didn't pay much for the two! Oh well. Thanks Rob.

[Tommy Tyler]

I'm sorry to have come in late on this, but in case this problem comes up again here are some ideas on how to tell that an EEPROM is alive and well. The first thing to do is quit trying to use the blinks of the red LED to tell you if the EEPROM is working. Those blinks might or might not tell you if an upload or download was successful, but that's not their primary purpose. You should rely instead on the little red simulated LED at the lower left corner of the IR display. If that indicator blinks twice at the end of an operation you can rest assured that the EEPROM is at least sending or receiving properly, because each byte sent to or from the EEPROM has to be acknowledged by the receiving unit.

Remember that when an interface uploads and downloads an EEPROM it is in total control, because it puts the uP to sleep so it has exclusive use of SDA and SCL. So if you have a known working interface you can tell whether an EEPROM is alive and well by just uploading and downloading a text file. You can even make up your own test file using Notepad or any text editor. Type just a line consisting of 16 pairs of the letter "a" (or any other hexadecimal characters), with a single space separating each pair. You don't need line numbers or anything else. Give the file a name, and save it.

Open IR.exe and click on the "Raw Data" tab. Click on "Advanced" and "Purge Memory" to fill the data buffer with all "F's". If asked, just accept the default EEPROM size of "$0800". Now click on "File", "Open", and select the 1-line text file you made. Disregard any warnings about signature, etc.

Upload to the remote. If the IR indicator blinks twice the EEPROM has received your data. Disregard the LED blinks of the remote. The uP is not happy with what you've sent, but he can't do a thing about it.

Now, to verify that the EEPROM actually stored your data, purge the IR data buffer as before, then do a download. Again, watch for the double blink of the IR indicator. If you get back your 1-line data file you know the EEPROM saved it.

This test can be used to eliminate the EEprom as a possible cause of problems you're having. If you're worried that the first 16 bytes in the EEprom may be good, but another part may be faulty, you can either expand your test file as much as you like, or just use any EEprom text file you can find, even if it's not for your remote. IR will get all excited over this and threaten you about signatures, checksums, and the like. Just ignore him.

After playing with bogus files you'll have to use the 980 and/or 981 resets to bring your remote out of its shock. Never try to test a newly built interface and a newly installed EEPROM at the same time. Either qualify the interface on a known good remote, or test the EEPROM with a known good interface.