ISD1790 spi_xfer

[aefelgate]

Hello,

I am attempting to use the software spi_xfer function to interface to an ISD1790 voice chip. This chip has variable length commands, and variable length responses clocked out.

I am seeing some bits coming out of the ISD1790 chip as I clock in commands to it. The bit stream doesn't make sense at face value--I'm wondering if I have to swap nibbles/bytes in the received response? Some responses are 16 bits, some are 24 bits (that's an odd one to map to a variable) and others are 32 bits. The chip requires LSB_FIRST, and I am using the #use spi directive to set it up.

My main question is regarding whether or not I need to swap bytes/nibbles in the response?

Thanks for any assistance!