add UART RX

main.c

@@ -76,6 +76,9 @@ static volatile uint8_t nec_msg[4] = {0};
 // flag set if NEC message has been received
 static volatile bool nec_flag = false;
 
+// set when data is received over UART
+static volatile char uart_c = 0;
+
 // blocking wait (in 10 us steps, up to UINT32_MAX / 10)
 static void wait_10us(uint32_t us10)
 {
@@ -285,6 +288,10 @@ void main(void)
 	UART1->BRR2.reg = 0x0B; // set baud rate to 115200 (at 16 MHz)
 	UART1->BRR1.reg = 0x08; // set baud rate to 115200 (at 16 MHz)
 	UART1->CR2.fields.TEN = 1; // enable TX
+	UART1->CR2.fields.REN = 1; // enable RX
+	UART1->CR2.fields.RIEN = 1; // enable RX interrupt
+	char uart_cmd[10]; // buffer for received data
+	uint8_t uart_used = 0; // how much of the buffer is used
 
 	// configure IR demodulator pin
 	IRM_ON_PORT->ODR.reg &= ~IRM_ON_PIN; // switch IR demodulator off
@@ -421,6 +428,16 @@ void main(void)
 			led_blue(0); // ensure LED is off
 			halt();
 		}
+		if (uart_c) { // data received over UART
+			putc(uart_c); // echo back
+			if ('\r' == uart_c || '\n' == uart_c) { // end of line received
+				uart_used = 0; // reset buffer
+			} else if (uart_used < ARRAY_LENGTH(uart_cmd)) {
+				uart_cmd[uart_used++] = uart_c;
+			}
+			uart_c = 0; // clear flag
+			action = true; // redo main loop
+		}
 		if (action) { // something has been performed, check if other flags have been set meanwhile
 			action = false; // clear flag
 		} else { // nothing down
@@ -495,3 +512,11 @@ void nec_cc_isr(void) __interrupt(IRQ_TIM1_CC)
 		TIM1->SR1.fields.CC2IF = 0; // clear flag
 	}
 }
+
+// UART RX interrupt
+void rx_isr(void) __interrupt(IRQ_UART1_RX)
+{
+	if (UART1->SR.fields.RXNE) { // there is data
+		uart_c = UART1->DR.reg; // read received data, also clears flag
+	}
+}