/**
* A way of dynamically configuring the serial instance to use pins other than USBTX and USBRX.
*
* @param tx the new transmission pin.
*
* @param rx the new reception pin.
*
* @return MICROBIT_SERIAL_IN_USE if another fiber is currently transmitting or receiving, otherwise MICROBIT_OK.
*/
int MicroBitSerial::redirect(PinName tx, PinName rx)
{
if(txInUse() || rxInUse())
return MICROBIT_SERIAL_IN_USE;
lockTx();
lockRx();
if(txBufferedSize() > 0)
detach(Serial::TxIrq);
detach(Serial::RxIrq);
serial_free(&_serial);
serial_init(&_serial, tx, rx);
attach(this, &MicroBitSerial::dataReceived, Serial::RxIrq);
if(txBufferedSize() > 0)
attach(this, &MicroBitSerial::dataWritten, Serial::TxIrq);
this->baud(this->baudrate);
unlockRx();
unlockTx();
return MICROBIT_OK;
}
/**
* An internal method that either spin waits if mode is set to SYNC_SPINWAIT
* or puts the fiber to sleep if the mode is set to SYNC_SLEEP
*
* @param mode the selected mode, one of: ASYNC, SYNC_SPINWAIT, SYNC_SLEEP
*/
void MicroBitSerial::send(MicroBitSerialMode mode)
{
if(mode == SYNC_SPINWAIT)
while(txBufferedSize() > 0);
if(mode == SYNC_SLEEP)
fiber_sleep(0);
}
/**
* Copies characters into the buffer used for Transmitting to the central device.
*
* @param buf a buffer containing length number of bytes.
* @param length the size of the buffer.
* @param mode the selected mode, one of: ASYNC, SYNC_SPINWAIT, SYNC_SLEEP. Each mode
* gives a different behaviour:
*
* ASYNC - Will copy as many characters as it can into the buffer for transmission,
* and return control to the user.
*
* SYNC_SPINWAIT - will return MICROBIT_INVALID_PARAMETER
*
* SYNC_SLEEP - Will perform a cooperative blocking wait until all
* given characters have been received by the connected
* device.
*
* @return the number of characters written, or MICROBIT_NOT_SUPPORTED if there is
* no connected device, or the connected device has not enabled indications.
*/
int MicroBitUARTService::send(const uint8_t *buf, int length, MicroBitSerialMode mode)
{
if(length < 1 || mode == SYNC_SPINWAIT)
return MICROBIT_INVALID_PARAMETER;
bool updatesEnabled = false;
ble.gattServer().areUpdatesEnabled(*txCharacteristic, &updatesEnabled);
if(!ble.getGapState().connected && !updatesEnabled)
return MICROBIT_NOT_SUPPORTED;
int bytesWritten = 0;
while(bytesWritten < length && ble.getGapState().connected && updatesEnabled)
{
for(int bufferIterator = bytesWritten; bufferIterator < length; bufferIterator++)
{
int nextHead = (txBufferHead + 1) % txBufferSize;
if(nextHead != txBufferTail)
{
txBuffer[txBufferHead] = buf[bufferIterator];
txBufferHead = nextHead;
bytesWritten++;
}
}
int size = txBufferedSize();
uint8_t temp[size];
memclr(&temp, size);
circularCopy(txBuffer, txBufferSize, temp, txBufferTail, txBufferHead);
if(mode == SYNC_SLEEP)
fiber_wake_on_event(MICROBIT_ID_NOTIFY, MICROBIT_UART_S_EVT_TX_EMPTY);
ble.gattServer().write(txCharacteristic->getValueAttribute().getHandle(), temp, size);
if(mode == SYNC_SLEEP)
schedule();
else
break;
ble.gattServer().areUpdatesEnabled(*txCharacteristic, &updatesEnabled);
}
return bytesWritten;
}
