I understand the difference between both asynch- and synchronous transmission and the advantage of the second one.

Does SPI require always 2 way communication setup? I don't see my display sending some data back to the PIC, does it?

What is the RS line for?

Starting to build-up an SPI communication, I'll need to configure the SSP module by firstly switch it ON (SSPCON.5 = 1). Then, according to my display's datasheet, I think the data is transmitted on rising edge but the setting depends on the CKP mode which I don't know what it is about ?!

Next, there seems to be several ways to send the data; either using SHIFTOUT command or via registers (SSPBUF). Which one is the better way of doing?

What about speed. My display works at 400kbits/s (or am I wrong), what will be the "safest" setting?

Name:  4-wire SPI example.jpg
Views: 1483
Size:  25.9 KB

PS: I'l be on holiday this week...