I'm sending API data packets on a Series 1 Xbee, 802.15.4, once every 25ms. The packet transmits successfully and is received by a 2nd Xbee successfully almost all of the time but every minute or so at random intervals, the receiving Xbee doesn't send the packet out of its uart port.
I have tried different Xbees at both ends, set up with both devices as End Devices, transmitting and receiving with 16-bit addressing, and I've tried the transmitter as an End Device, associated with a Coordinator as the receiver, using 64-bit addressing.
I am communicating at a nominal 115200 baud rate and have checked that all uarts are communicating at the real Xbee rate of 111111 baud.
The communication is two way, so that the receiving end returns a packet to the transmitter within the 25ms time slot.All waveforms on a scope look good except for the single random dropouts, when the Rx device fails to transmit the received packet out of its uart.
I have checked that the packet being transmitted is correct when the failure occurs, including packet length bytes and checksum; the packet is <20 bytes long in both directions.
I have tried this both wirelessly and with a wired connection between the two xbee connectors.
Can't really see where this is going wrong, so is there something I'm missing or any way of diagnosing what's happening ?