Hi,
I am currently testing CCA with interrupts: http://e2e.ti.com/support/wireless_connectivity/f/156/t/370115.aspx.
I noticed that sometimes I did not register interrupt with AVR. AVR spec says that signal must be high at least 50 ns.
CC1200 userguide tabel 10 says, that pulse interrupt is 2 XOSC periods which is 50 ns if 40 MHz crystal is used. So this is quite tight and I can see with oscilloscope that sometimes G2 signal is high only 20 ns (it takes some time to reach it). Therefore this 50 ns is not guaranteed.
My question is, is there any trick that I could do to make this period longer. My goal is to use CCA with interrupts - I would like to get an interrupt when radio is finished doing CCA [IOCFG2 = 15;].
EDIT:
I was thinking that maybe doing CCA with interrupts is not that important, because CCA seems to finish almost immediately after sending STX. There is only 1.5 us between sending STX and getting CCA done interrupt.
Could you tell me if this will vary in some cases. Should I check anything else besides radio being in RX state while STX is made (RSSI valid, etc..)?
Andres