CPLD - I2c - Logic Usage

[FvM]

Anyhow, i didn't understood your last two lines.

CNS means central nervous system. mrflibble tried to understand why you still keep the idea of performing I2C communication with the chip, although it's apparently over your head and you already got a pretty strong hint to better use SPI.

Accepting his criticism, I won't any longer harp on about possible I2C solutions.

 

[mrflibble]

So are you concluding by telling to use spi rather than I2c ? Anyhow, i didn't understood your last two lines.

Yes, pretty much. I would really suggest you use SPI rather than I2C. I have absolutely nothing against i2c, but in the context of cpld/fpga it is so much easier/cheaper/lower-resources to do it with SPI. Even "just snooping/eavesdropping" on the I2C bus is going to cost more compared to SPI.

So I consider the choice of "what type of interface to use between fpga and temperature sensor" to be a solved problem. The thing that is still unclear after asking a few times is what the connection between main module and fpga is like. Do you have 100% control there as well? If the pincount on the main module allows it I would just make that SPI as well. Yes, I like SPI ... because it's simple and Just Works [tm]. But if on the main controller it MUST be i2c for some reason (if so, what reason?) then you will have to make an I2C slave implementation on the fpga, and connect that to the main module. But again, if you have the freedom make it spi.

The main reasons why I sometimes use i2c instead of spi are basically either 1) pincount or 2) availability of certain chippie only in i2c flavor. I hope that clarifies things.