From 1fdf3f18b7a4cadf0ece2dbeb7d5d8ab479fcf9c Mon Sep 17 00:00:00 2001
From: Xoaquin Castrelo <xoaquin.cb@gmail.com>
Date: Sun, 14 Nov 2021 04:38:59 +0000
Subject: [PATCH] Enabled writing to UART.
---
emb/uart.cpp | 11 ++++++-----
emb/uart.hpp | 7 +++++++
2 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/emb/uart.cpp b/emb/uart.cpp
index 0308b8b..003d682 100644
--- a/emb/uart.cpp
+++ b/emb/uart.cpp
@@ -12,7 +12,6 @@ void initUart()
UCSR0A = (1 << U2X0); // double transmission speed
UCSR0B = (1 << RXCIE0) // enable RX complete interrupt
- | (1 << UDRIE0) // enable data register empty interrupt
| (1 << RXEN0) // enable receiver
| (1 << TXEN0); // enable transmitter
UCSR0C = (0 << UMSEL01) | (0 << UMSEL00) // asynchronous USART
@@ -25,12 +24,14 @@ void initUart()
sei();
}
-ISR(USART_RX_vect)
+void writeUart(uint8_t value)
{
- uart_add_ch(UDR0);
+ while (!(UCSR0A & (1 << UDRE0)));
+
+ UDR0 = value;
}
-ISR(USART_UDRE_vect)
+ISR(USART_RX_vect)
{
- // nothing to do right now
+ uart_add_ch(UDR0);
}
diff --git a/emb/uart.hpp b/emb/uart.hpp
index 2a10f18..b391efd 100644
--- a/emb/uart.hpp
+++ b/emb/uart.hpp
@@ -1,9 +1,16 @@
#ifndef UART_H
#define UART_H
+#include <stdint.h>
+
/**
* Initialises the UART logic.
*/
void initUart();
+/**
+ * Writes a character to the UART port.
+ */
+void writeUart(uint8_t value);
+
#endif /* UART_H */
--
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