Flowcode Support Board

Hi there,

Seems I2C module (hardware mode 100Kbit) on PIC32MX130F064D is not acknowledging any READ at all. Is this a known issue? I'm running latest FC9 version.

I have enabled Slew Rate as well as SMB options, but same issue is seen.

I have attached scope trace highlighting the issue.
The I2C READ routine is exactly the same as the one from the I2C sample FCX files we've been using for years.
Thanks for taking a look at this!

Hello,

When reading bytes the ack is used as a flag to let the slave know if any more bytes are going to be read. This is the "Last" parameter of the Receive Byte macro.

If last is set to 0 then the byte should be acked and if last is set to 1 then the byte is nacked.

Hopefully this helps.

Hi Ben,

Thanks for clarifying, this makes sense! All is working perfectly well now
Cheers!
R

Just noticed the line stays low, so always 1 is needed for last ReceiveByte and should I assume there will never be an ACK? I guess this is how I2C works... I was expecting always an ACK, but I was wrong it seems...

Yes, as Ben said, on receiving the last byte (from Slave to Master) a NAK is sent (to tell the Slave that no more bytes required)