From 3e98fbcdc8d862f9725d5b5fa6331620c2a0ff76 Mon Sep 17 00:00:00 2001
From: Ayke van Laethem <aykevanlaethem@gmail.com>
Date: Thu, 4 Oct 2018 13:36:38 +0200
Subject: [PATCH] avr: use machine.UART0 as stdout

---
 src/machine/machine_avr.go |  7 +++++--
 src/runtime/runtime_avr.go | 13 +++----------
 2 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/src/machine/machine_avr.go b/src/machine/machine_avr.go
index ff02d052..993276d3 100644
--- a/src/machine/machine_avr.go
+++ b/src/machine/machine_avr.go
@@ -291,8 +291,11 @@ func (uart UART) Configure(config UARTConfig) {
 	*avr.UBRR0H = avr.RegValue(ps >> 8)
 	*avr.UBRR0L = avr.RegValue(ps & 0xff)
 
-	// enable RX interrupt
-	*avr.UCSR0B |= avr.UCSR0B_RXCIE0
+	// enable RX, TX and RX interrupt
+	*avr.UCSR0B = avr.UCSR0B_RXEN0 | avr.UCSR0B_TXEN0 | avr.UCSR0B_RXCIE0
+
+	// 8-bits data
+	*avr.UCSR0C = avr.UCSR0C_UCSZ01 | avr.UCSR0C_UCSZ00
 }
 
 // WriteByte writes a byte of data to the UART.
diff --git a/src/runtime/runtime_avr.go b/src/runtime/runtime_avr.go
index 6c369ff0..070e146d 100644
--- a/src/runtime/runtime_avr.go
+++ b/src/runtime/runtime_avr.go
@@ -4,6 +4,7 @@ package runtime
 
 import (
 	"device/avr"
+	"machine"
 	"unsafe"
 )
 
@@ -54,19 +55,11 @@ func init() {
 }
 
 func initUART() {
-	// Initialize UART at 9600 baud when running at 16MHz.
-	*avr.UBRR0H = 0
-	*avr.UBRR0L = 0x67
-
-	*avr.UCSR0B = avr.UCSR0B_RXEN0 | avr.UCSR0B_TXEN0   // enable RX and TX
-	*avr.UCSR0C = avr.UCSR0C_UCSZ01 | avr.UCSR0C_UCSZ00 // 8-bits data
+	machine.UART0.Configure(machine.UARTConfig{})
 }
 
 func putchar(c byte) {
-	for (*avr.UCSR0A & avr.UCSR0A_UDRE0) == 0 {
-		// Wait until previous char has been sent.
-	}
-	*avr.UDR0 = avr.RegValue(c) // send char
+	machine.UART0.WriteByte(c)
 }
 
 // Sleep this number of ticks of 16ms.