changed to use USART2

init.c

@@ -11,8 +11,8 @@ void init_gpios(void)
 	gpio_enable(GPIOB);
 	gpio_enable(GPIOC);
 
-	gpio_set_mode(GPIOC, BIT8 | BIT9 | BIT7, MODER_OUTPUT);
-	gpio_set_mode(GPIOA, BIT0, MODER_INPUT);
+	// LEDs
+	gpio_set_mode(GPIOC, BIT8 | BIT9, MODER_OUTPUT);
 }
 
 
@@ -38,21 +38,21 @@ void init_clock(void)
 
 void init_usart(void)
 {
-	gpio_set_af(GPIOC, BIT10 | BIT11, AF7);
+	gpio_set_af(GPIOA, BIT2 | BIT3, AF7);
 
-	// USART at C10 (tx), C11 (rx)
-	RCC_APB1ENR |= RCC_APB1ENR_USART3EN;
+	// USART at A2 (tx), A3 (rx)
+	RCC_APB1ENR |= RCC_APB1ENR_USART2EN;
 
 	// RATE 9600Bd 104.1875 (see datasheet for reference)
-	//USART3_BRR = 0x00683; // 9600 @ 16MHz
-	USART3_BRR = 0x0008A; // 115200 @ 16MHz
+	//USART2_BRR = 0x00683; // 9600 @ 16MHz
+	USART2_BRR = 0x0008A; // 115200 @ 16MHz
 
 	// USART enable
-	USART3_CR1 = USART_CR1_UE | USART_CR1_RE | USART_CR1_TE;
+	USART2_CR1 = USART_CR1_UE | USART_CR1_RE | USART_CR1_TE;
 
 	// enable interrupt on data receive
-	nvic_enable_irq(NVIC_USART3_IRQ);
-	USART3_CR1 |= USART_CR1_RXNEIE;
+	nvic_enable_irq(NVIC_USART2_IRQ);
+	USART2_CR1 |= USART_CR1_RXNEIE;
 }
 
 
@@ -67,6 +67,8 @@ void init_systick(void)
 
 void init_adc(void)
 {
+	gpio_set_mode(GPIOB, BIT12, MODER_ANALOG);
+
 	// TODO
 }
 

main.c

@@ -14,19 +14,21 @@ void say_hello(void)
 
 
 /** IRQ */
-void USART3_IRQHandler(void)
+void USART2_IRQHandler(void)
 {
-	if (USART3_SR & USART_SR_ORE) {
-		USART3_SR &= ~USART_SR_ORE;
-		return;
+	// RXIE enables also ORE - must handle ORE.
+	if (USART2_SR & USART_SR_ORE) {
+		USART2_SR &= ~USART_SR_ORE;
 	}
 
-	blue_blink();
+	if (USART2_SR & USART_SR_RXNE) {
+		blue_blink();
 
-	char c = usart_rx_char(USART3);
-	usart_tx_char(USART3, c);
+		char c = usart_rx_char(USART2);
+		usart_tx_char(USART2, c);
 
-	USART3_SR ^= USART_SR_RXNE;
+		USART2_SR ^= USART_SR_RXNE;
+	}
 }