Hello, I'm hoping that someone here has used the Transmit FIFO functionality of the XC164 and can offer some tips on how to get it configured and running. I want to use an interrupt routine to buffer incoming serial data until a complete message is received, use the foreground loop to process and build the reply, and then use another interrupt routine to transmit the reply (like many others before me, I'm sure!). I've implemented the receive interrupt using the Receive FIFO and the foreground processing, and they work nicely. However, I can not get the Transmit FIFO to work properly. I've made settings for the Transmit FIFO in DAvE following similar logic from configuring the Receive FIFO, but the resulting interrupt processing doesn't quite make sense when compared to what (I think) I'm reading in the datasheet. Currently I'm falling back to using printf() to get the reply out. I've read (and re-read and re-read) the XC164 Data Sheet but it is not sinking in. If someone could explain the procedure they've used I'm sure I could get this working. Best regards, Max Peelman