Light Buddy Firmware (part 5)

After installing the LP5569 on one PCB the other day I have been struggling for two days to talk them.  Being 4x4mm 28 pin parts, I decided to use the reflow toaster oven to put these parts down.  While I could not find any shorts, there was no acknowledgement.

This forced me to get out my USBEE device to look at the I2C bus to make sure it was doing what it was supposed to. It confirmed that no ACK was coming back, but that the data coming out of the PIC was OK.

What I did notice though was that while I was only reading this address, the display was showing either a read or a write depending on which chip I was trying to address.  That is not right.  I went back to the data sheet to look at addresses.  Most of my experience in I2C has been where the address is in 8-bit format and the Bit 0 is not used, so you just put the address in as listed.  As you can see from this figure, that is not the case with the LP5569.  The actual byte value used needs to be shifted left one bit. 

The lesson here is to always READ THE DATA SHEET first.