We have the AX5043 receiving 60 kbps MSK HDLC packets at 436.5 MHz. We have long but relatively sane data packet sizes of 2-3K. The internal FIFO of the AX5043 only handles 240 bytes, so we take the the large data packets out in FIFO-sized chunks. The AX5043 should set the PKTSTART and PKTEND bits, so that we know which FIFO chunks are the start of a new packet and when a packet ends.
However, the PKTSTART bit is always 1. We’ve experimented with all sorts of chunk sizes, with all sorts of packet sizes, and no matter what PKTSTART is always set. PKTSTART is even set when PKTEND is set, which seems wrong. This, of course, means that we can’t tell what’s a large packet size and what’s a new small packet and the only packets that get through are less than 240 bytes.
Is there, somewhere, a non-obvious bit to set to enable PKTSTART to work as we expect?