Author Topic: Problem Programming I2C eeprom IN circuit - FV1 DIY eval Board  (Read 252 times)

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Carlos Best

Problem Programming I2C eeprom IN circuit - FV1 DIY eval Board
« on: November 03, 2017, 09:02:55 AM »
Guys
I'm trying to develop my own FV-1 Eval Board to see if I can cook some tasty effects.  :icon_lol:
I'm basically using the Slackers Babelfish schem with a rotative switch to select the programs.
http://www.aronnelson.com/gallery/main.php/v/slackers-stuff/babelfish/babelfishschem.jpg.html?g2_imageViewsIndex=1

I bought an inexpensive CH341A eeprom programmer for programming the onboard eeprom 24LC34.

In circuit I isolated the 3v3 line of the eeprom from the rest of the board so thats not conected when I plug the programmer.

I just can't manage to make it work. I don't know if I need pull up resistors, so I tried tying a 2 x 1k5 from 3v3 to each SCK/SDA lines, but with no results.
The memory works using the zero force socket

The voltages of the eeprom in the programmer socket are

1, 2, 3, 4, 7: 0
5 and 6: 5v (usb powered)
8: 3v3

The voltages of the eeprom IN Circuit are
1, 2, 3, 4, 7: 0
5 and 6: 1.6 v
8: 3v3

So I imagine the FV.1 or other component is pulling the lines down.

What do I check?

Thanks in advance
Regards

Carlos Best

Re: Problem Programming I2C eeprom IN circuit - FV1 DIY eval Board
« Reply #1 on: November 03, 2017, 11:16:44 AM »
Well, looks like my suspicions were true

I had cut the wires that conects de data and clock lines from the 24LC32 to the fv1 and tried reading and programming.
Works like a charm.

Maybe is the programmer that sets high (5v) clock and data and the FV1 loads that thus the programmer doesnt work?
I don't have at my disposal anyone who can borrow another type of burner so I can try that.

potul

Re: Problem Programming I2C eeprom IN circuit - FV1 DIY eval Board
« Reply #2 on: November 05, 2017, 06:04:54 PM »
Hola Coco, cuanto tiempo!

If I'm not mistaken, the FV-1 should be pulling up the memory lines.
I had a similar issue with my FV-1 board. I couldn't program the memory on board, and I could only program it by adding pull up resistors. But then, my FV-1 didn't work. I checked all pins voltages, and I had 1.6v in some pins I should have 3.3v.
I did a reflow of all the solders and the issue was still there. I did an in deep flux residue cleanup and this fixed everything, including the memory programming.

So my advice would be to check if the FV-1 is operating at the right voltages everywhere. And ensure you don't have any residual flux.

Good luck!

Mat.

pruttelherrie

Re: Problem Programming I2C eeprom IN circuit - FV1 DIY eval Board
« Reply #3 on: November 11, 2017, 04:20:59 AM »
On my own board I don't use pull-ups. I use a Pickit2 for programming, and while progamming in-circuit works, I do need to disconnect it when I want to test.

Ice-9

Re: Problem Programming I2C eeprom IN circuit - FV1 DIY eval Board
« Reply #4 on: November 11, 2017, 04:58:45 AM »
The Fv-1 has internal pull ups on the SDA/SCL lines.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !
Do me a lemon, that a poor IQ for a glass of water.