From a09ebf4a690b86b7cc629d3c1a9e18c4ab4fc097 Mon Sep 17 00:00:00 2001
From: David Lamparter <equinox@diac24.net>
Date: Thu, 17 May 2012 02:30:01 +0200
Subject: uart: volatile/uart_wait()

---
 uart.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/uart.c b/uart.c
index fcc5783..feb9619 100644
--- a/uart.c
+++ b/uart.c
@@ -1,6 +1,6 @@
 #define TXBSIZE 128
-static char txbuf[TXBSIZE];
-static uint8_t txput = 0, txsend = 0;
+static volatile char txbuf[TXBSIZE];
+static volatile uint8_t txput = 0, txsend = 0;
 
 ISR(USART_RX_vect)
 {
@@ -19,6 +19,12 @@ ISR(USART_UDRE_vect)
 	}
 }
 
+static void uart_wait(void)
+{
+	while (txsend != txput)
+		asm volatile ("" : : : "memory");
+}
+
 static void _uart_putch(const char ch)
 {
 	txbuf[txput] = ch;
-- 
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