Xmega Usart Example Generator Scale Factor

Synchronous clock rates up to of the device clock frequency and asynchronous clock rates up to 18 of the device clock frequency.

The USART in XMEGA is almost very similar to USART in Mega AVRs.

Only the register names are different for XMEGA than that of Mega AVRs.

Here we need to define direction of RXD pin as input and direction of TXD pin as output.

TXD0 as output and PC2 i.e.

Those flags are receive complete interrupt flag, transmit complete interrupt flag, data register empty flag, frame error flag, buffer overflow flag, parity error flag and RXB8 flag.

Out of above flags we need to check only two flags, first RXCIF flag to check if there is any unread data in receive data buffer and second DREIF flag to check if the data receive buffer is ready to receive new data or not.

This bit is effective only in USART asynchronous communication mode.

The MPCM bit in this register enables the multiprocessor communication mode.

The more details of multiprocessor communication mode are available in datasheet.

USARTC0CTRLBUSARTRXENbmUSARTTXENbm; enable usart receiver and transmitter.

USARTC0CTRLCUSARTCHSIZE1bmUSARTCHSIZE0bm; asynchronous usart char size 8-bit, 1 stop bit, no parity.

Xmega Usart Example Generator Scale Factor

The higher nibble of this register contains baud rate generator scale factor.

The scale factor is given 2s compliment form from -7 (0b1001) to 7 (0b0111).

We will select BSCALE value as one for simplicity.