UART Basics

embedded/atsams70-tinyrouter/atsams70-tinyrouter/src/main.c

@@ -35,6 +35,8 @@ pin_t stlb;
 pin_t stlr;
 pin_t button;
 
+pin_t p3lr;
+
 int main (void)
 {
 	/* Insert system clock initialization code here (sysclk_init()). */
@@ -45,6 +47,9 @@ int main (void)
 	PMC->PMC_PCER0 = 1 << ID_PIOA;
 	PMC->PMC_PCER0 = 1 << ID_PIOD;
 	
+	p3lr = pin_new(PIOD, PIO_PER_P10);
+	pin_output(p3lr);
+	
 	stlb = pin_new(PIOA, PIO_PER_P1);
 	pin_output(stlb);
 	
@@ -54,13 +59,33 @@ int main (void)
 	button = pin_new(PIOA, PIO_PER_P15);
 	pin_input(button);
 	
+	PMC->PMC_PCER1 = 1 << 14; // UART4 go clock go
+	
+	PIOD->PIO_PDR = PIO_PER_P18;
+	PIOD->PIO_PDR = PIO_PER_P19;
+	
+	PIOD->PIO_ABCDSR[0] = ~PIO_PER_P18;
+	PIOD->PIO_ABCDSR[0] = ~PIO_PER_P19;
+	PIOD->PIO_ABCDSR[1] = PIO_PER_P18;
+	PIOD->PIO_ABCDSR[1] = PIO_PER_P19;
+  	
+	UART4->UART_MR = UART_MR_BRSRCCK_PERIPH_CLK | UART_MR_CHMODE_NORMAL;
+	UART4->UART_BRGR = 32; // clock / this value * 16
+	UART4->UART_CR = UART_CR_TXEN | UART_CR_RXEN;
+	
 	while(1){
-		if(pin_get_state(button)){
+		if(pin_get_state(button)){ // hi, button is not pressed
 			pin_clear(stlb);
 			pin_set(stlr);
+			while(!(UART4->UART_SR & UART_SR_TXRDY)){ // wait for ready
+				pin_clear(p3lr);
+			}
+			pin_set(p3lr);
+			UART4->UART_THR = 85;
 		} else {
 			pin_set(stlb);
 			pin_clear(stlr);
+			pin_set(p3lr);
 		}
 	}
 }