SSP: How does SSP Slave detect end of packet?

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by capiman on Sat Mar 14 12:12:02 MST 2015

I am currently thinking about a general problem with SSP Slave, perhaps I have overseen something?

I am implementing a SSP slave (SPI Format). SSP Master is lower CS and transmits some data to me.
I get an interrupt, when the receive FIFO has data and I can read them. So far so good.
Now when SSP Master is setting CS back to high, how do I recognize that the packet is complete?
Or take the case, the SSP Master is setting CS back to high and back to low to start a new packet,
how do I recognize that a new packet has started? Is there any bit which signals that packet is complete or a new one is started?
(Especially also interesting with variable length data per packet.)

Or do I need to sample the CS again and again (or at a certain position) to recognize it is not more low?

Best regards,