/** Checks for new bytes available from the wireless radio
* and processes all that are available. */
void processBytesFromRadio()
{
uint8 i, n;
uint8 XDATA *rcv;
rcv = radioLinkRxCurrentPacket();
if(rcv != NULL) {
n = rcv[0]; // payload length
for(i = 1; i <= n && radioLinkTxAvailable(); i++) {
processByte(rcv[i]);
}
radioLinkRxDoneWithPacket();
}
}
uint8 radioComTxAvailable(void)
{
if (sendSignalsSoon)
{
// We want to send the control signals ASAP, but have not yet been able to
// queue a packet for them. Return 0 because we don't want to accept any
// more data bytes until we queue up those control signals. This is part of
// the plan to ensure that everything is processed in the right order.
return 0;
}
else
{
// Assumption: If txBytesLoaded is non-zero, radioLinkTxAvailable will be non-zero,
// so the subtraction below does not overflow.
// Assumption: The multiplication below does not overflow ever.
return radioLinkTxAvailable()*RADIO_LINK_PAYLOAD_SIZE - txBytesLoaded;
}
}
void radioComTxService(void)
{
if (radioLinkResetPacketReceived)
{
// The other device has sent us a reset packet, which means it has been
// reset. We should send the state of the control signals to it.
radioLinkResetPacketReceived = 0;
sendSignalsSoon = 1;
}
if (sendSignalsSoon)
{
// We want to send the control signals ASAP.
// NOTE: The if statement below could probably be moved to radioComTxControlSignals()
// and then you could add the assumption here that txBytesLoaded is 0
// (we are not in the middle of populating a data packet).
if (txBytesLoaded != 0)
{
// There is normal data that needs to be sent before the control signals,
// so send it now.
radioComSendDataNow();
}
if (radioLinkTxAvailable())
{
radioComSendControlSignalsNow();
}
}
else
{
// We don't need to send control signals ASAP, so we use the normal policy
// for sending data: only send a non-full packet if the number of packets
// queued in the lower level drops below the TX_QUEUE_THRESHOLD.
if (txBytesLoaded != 0 && radioLinkTxQueued() <= TX_QUEUE_THRESHOLD)
{
radioComSendDataNow();
}
}
}
