Thanks thats pretty encouraging.
You don't need 24 chip selects, you can daisy=chain the TPICs from the SPI pins just like you do with ShiftOut. So one CS pin for all the TPICs.
OK so I will use MOSI for the data, clock for clock, and CS for latch .
The RF22 presumably sets the polarity, speed, etc for the SPI, so I will just fit in with that with a different CS pin?
Or, if you can afford to wait a few microseconds before servicing the interrupt (which depends on whether the receiver can buffer incoming data), then you can disable interrupts while you send data to the TPICs.
I usually send the transmission several times anyway to be sure ( its just updates of scores now and again ) so I can disable interupts while refreshing each rows data. ( if the SPI is fast enough there should be time before the next refresh using GMikes timing check )
I also have a countdown clock that I use "blink without delay" routine for, using millis(), will this be OK ?
Use an array with 8 bytes per 8x8 display, one byte for each row. Shift out the bytes for the rows you want to update.
Thats basically what I am putting together now for the test which I was going to try with shiftout, but I will try SPI instead.
Can I send out 24 bytes in one go while the CS is low, and then raise it to latch the data?
I'm afraid the example with the LCD display is confusing for me at the moment, I will try my baby steps method to get it running with one panel, and see what happens with 35 LEDs up against the African sun in the morning.