DS2502 returns FF

[jensvanhoof86]

Hi,

EDIT: I could be completely wrong, but is it possible that the schematic is not correct? If I'm using an arduino for the I/O and PRGRM, shouldn't R4 and R1 be pulling up to VCC of the Arduino (3.3V or 5V) instead of 12V?

EDIT: It's actually not FF all the time, values do change but it's different every time. I'm now wondering if I have already mis-programmed the chip since it's read-only.. I've got a couple more chips here but I'm trying avoid going wrong through them all.. :-)

I built the programming circuit on a breadboard in an attempt to program a DS2502 with an Arduino Uno.

It seems like the sketch communicates correctly with the DS2502 but the read back always returns 0xFF, like none of the bytes are acutally written:

Nothing connected device present ROM Data is: 9 10 5F 31 A 0 0 C0 . ROM CRC matches Device ID DS2502 found PROG Memory programmed data: 44 read back: FF programmed data: 45 read back: FF programmed data: 4C read back: FF programmed data: 4C read back: FF programmed data: 30 read back: FF programmed data: 30 read back: FF programmed data: 41 read back: FF programmed data: 43 read back: FF programmed data: 30 read back: FF programmed data: 39 read back: FF programmed data: 30 read back: FF programmed data: 31 read back: FF programmed data: 39 read back: FF programmed data: 35 read back: FF programmed data: 30 read back: FF programmed data: 34 read back: FF programmed data: 36 read back: FF programmed data: 43 read back: FF programmed data: 4E read back: FF programmed data: 30 read back: FF programmed data: 39 read back: FF programmed data: 54 read back: FF Reading Memory Invalid command CRC! Calculated CRC:8D DS250x readback CRC:FF Stopped!!

Any ideas what could be wrong?

[garyStofer]

Hi , looks like the part is not getting programmed.., is the circuit correct ?? If the device doesn't get the proper programming voltage during the programming phase this would be the result.  An empty part reads all FF , except for the device signature. Gary On Feb 9, 2024, at 4:24 AM, jensvanhoof86 @.***> wrote: Hi, I built the programming circuit on a breadboard in an attempt to program a DS2502 with an Arduino Uno. It seems like the sketch communicates correctly with the DS2502 but the read back always returns 0xFF, like none of the bytes are acutally written: Nothing connected device present ROM Data is: 9 10 5F 31 A 0 0 C0 . ROM CRC matches Device ID DS2502 found PROG Memory programmed data: 44 read back: FF programmed data: 45 read back: FF programmed data: 4C read back: FF programmed data: 4C read back: FF programmed data: 30 read back: FF programmed data: 30 read back: FF programmed data: 41 read back: FF programmed data: 43 read back: FF programmed data: 30 read back: FF programmed data: 39 read back: FF programmed data: 30 read back: FF programmed data: 31 read back: FF programmed data: 39 read back: FF programmed data: 35 read back: FF programmed data: 30 read back: FF programmed data: 34 read back: FF programmed data: 36 read back: FF programmed data: 43 read back: FF programmed data: 4E read back: FF programmed data: 30 read back: FF programmed data: 39 read back: FF programmed data: 54 read back: FF Reading Memory Invalid command CRC! Calculated CRC:8D DS250x readback CRC:FF Stopped!! Any ideas what could be wrong?

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[jensvanhoof86]

yeah I feel like something is wrong with my circuit but I still haven't been able to figure it out. Is it correct that PRGM and I/O are pulled-up to 12V instead of the 5V/3.3V that the arduino uses? In the DS2502 datasheet they make a difference between VDD and 12V. I'm wondering if I have not killed anything on the arduino meanwhile.

[garyStofer]

I have to take a look at the circuit again myself. I use a 3 cell Lipo for the +12V input. The Arduino side is never to see the 12 V as it’s switched by a transistor on the circuit.

If you are in the US, you can send me your 2503’s and I can run them through my programmer – Cover shipping for the return .

Gary

From: jensvanhoof86 Sent: Monday, March 04, 2024 2:04 AM To: garyStofer/DS2502_DELL_PS Cc: Gary Stofer ; Comment Subject: Re: [garyStofer/DS2502_DELL_PS] DS2502 returns FF (Issue #5)

yeah I feel like something is wrong with my circuit but I still haven't been able to figure it out. Is it correct that PRGM and I/O are pulled-up to 12V instead of the 5V/3.3V that the arduino uses? In the DS2502 datasheet they make a difference between VDD and 12V. I'm wondering if I have not killed anything on the arduino meanwhile.

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[jensvanhoof86]

stop the presses! turns out I had 2 out of 3 mosfets broken! It works now!! Thanks a lot for the reply.

for future readers: I have connected R4, R1 and R2 to 5V instead of 12V. only R3 goes to the 12V.

[garyStofer]

Good job – Glad you figured it out !

G

From: jensvanhoof86 Sent: Monday, March 04, 2024 8:59 AM To: garyStofer/DS2502_DELL_PS Cc: Gary Stofer ; Comment Subject: Re: [garyStofer/DS2502_DELL_PS] DS2502 returns FF (Issue #5)

stop the presses! turns out I had 2 out of 3 mosfets broken! It works now!! Thanks a lot for the reply.

for future readers: I have connected R4, R1 and R2 to 5V instead of 12V. only R3 goes to the 12V.

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