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Author Topic: Please help me change the FT232BL internal factory default parameters  (Read 6571 times)


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Hi all. New to the forum but coming here after days of struggles and many hours of digging on the web.

 I want to replace the FT232BL chip in an older device that uses ATMEGA 128 and EEPROM 93C46. The problem is the developer of this device must have changed a factory default parameter inside the FT232BL and made the Atmega hex check for this value. If this value is different, the Atmega goes into a boot loop and heats up, and the program cannot communicate with it.

 I came to this conclusion after trying 6 different FT232BM and BL ICs, from various suppliers. None worked. So I analysed the USB view tool with the FT232BL connected WITHOUT the 93C46 EEPROM, and I found one difference that original IC had and all the new ones did not: Under the Configuration Descriptor section., on the bmAttributes" field, the chip has the value"0x80 (Bus powered)" and all the new chips I tried have the value "0xC0 (Bus powered Self powered)"

If I try to change this value with FT prog it will not write it because it will try to write it to the 93C46 external eeprom. This will not help me because the check is done on the internal parameters. The 93C46 EEPROM remains as the developer made it, but any new FT232BL is rejected by the rest of the board.

I should mention that if I put the original FT232BL back on the board, all works fine. So there is no fault. The only issue is making a new FT232BL identical to the original one so the board will accept it and use it.

I hope this makes sense. Please help me with any info. I'm not a coder so I don't have programming experience in that sense.