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I have successfully communicated (both read and write) on several eeprom with FTDI 4232H SPI.

However, this time I have a chip which has only a bidirectional data pin. I have hooked up both the SDO and SDI of the ftdi chip to this bidirectional data pin.

I was able to verify my write command with this chip. However, I'm unable to read from this device. It seems that the ftdi data out pin does not go HIZ after a write, but drives low. Hence, when I perform a read operation I read 0s.

Can anyone please shed some light on how to put the FTDI data out pin highZ ?

clun
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1 Answers1

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Response direct from FTDI Chip

If using MPSSE mode, what we would recommend doing with the SDO pin is this - redefine it as an input before doing a read - this prevents bus contention. Then set as an output before writing.

Opcode 0x80 allows setting pins as input or output. Contact FTDI Chip's support if you need further help.

Sathish
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Mike Green
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