To enable the receiver on the same UART, the initialization function should also turn on the receiver using the corresponding switch in the UART_CR1 register:
UART3_CR1 |= UART_CR1_TX_ENABLE | UART_CR1_RX_ENABLE;
This ensures that the receiving side of the transceiver is enabled too. To read data in polling mode, blocking until a character is received, we can use the following function, which will return the value of the byte read:
char uart3_read(void){ char c; volatile uint32_t reg; do { reg = UART3_SR; } while ((reg & UART_SR_RX_NOTEMPTY) == 0); c = (char)(UART3_DR & 0xff); return c;}
This way we can, for example, echo back to the console each character received from the host:
void main(void) { char c[2]; flash_set_waitstates(); ...
