From 06beadfe683809d68f30655b5caed25550df912e Mon Sep 17 00:00:00 2001
From: "Sebastian H. Gabrielli" <gabrielli@sebaweb.no>
Date: Wed, 6 Mar 2024 15:36:24 +0100
Subject: [PATCH 1/2] Add UART functionality

---
 .gitignore                              |  4 ++-
 prosjekt.X/main.c                       | 19 +++++++++-----
 prosjekt.X/nbproject/configurations.xml |  4 ++-
 prosjekt.X/uart.c                       | 25 ++++++++++++++++++
 prosjekt.X/uart.h                       | 35 +++++++++++++++++++++++++
 5 files changed, 78 insertions(+), 9 deletions(-)
 create mode 100644 prosjekt.X/uart.c
 create mode 100644 prosjekt.X/uart.h

diff --git a/.gitignore b/.gitignore
index d14efc5..f31b37b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,4 +26,6 @@
 # Large Files
 *.exe
 *.zip
-*.pdf
\ No newline at end of file
+*.pdf
+/prosjekt.X/build/
+/prosjekt.X/dist/
\ No newline at end of file
diff --git a/prosjekt.X/main.c b/prosjekt.X/main.c
index 5f964b3..b42afa9 100644
--- a/prosjekt.X/main.c
+++ b/prosjekt.X/main.c
@@ -5,14 +5,19 @@
  * Created on March 6, 2024, 12:34 PM
  */
 
+#define F_CPU 4E6
+
 #include <stdio.h>
 #include <stdlib.h>
+#include "uart.h"
+#include <util/delay.h>
 
-/*
- * 
- */
-int main(int argc, char** argv) {
-
-    return (EXIT_SUCCESS);
-}
+int main() {
+    init_uart((uint16_t)9600);
+    stdout = &USART_stream;
 
+    while (1) {
+        printf("Hello, world!\n");
+        _delay_ms(500);
+    }
+}
\ No newline at end of file
diff --git a/prosjekt.X/nbproject/configurations.xml b/prosjekt.X/nbproject/configurations.xml
index d7f88a4..e8e1b9c 100644
--- a/prosjekt.X/nbproject/configurations.xml
+++ b/prosjekt.X/nbproject/configurations.xml
@@ -4,6 +4,7 @@
     <logicalFolder name="HeaderFiles"
                    displayName="Header Files"
                    projectFiles="true">
+      <itemPath>uart.h</itemPath>
     </logicalFolder>
     <logicalFolder name="LinkerScript"
                    displayName="Linker Files"
@@ -13,6 +14,7 @@
                    displayName="Source Files"
                    projectFiles="true">
       <itemPath>main.c</itemPath>
+      <itemPath>uart.c</itemPath>
     </logicalFolder>
     <logicalFolder name="ExternalFiles"
                    displayName="Important Files"
@@ -28,7 +30,7 @@
         <targetDevice>AVR128DB48</targetDevice>
         <targetHeader></targetHeader>
         <targetPluginBoard></targetPluginBoard>
-        <platformTool>noID</platformTool>
+        <platformTool>nEdbgTool</platformTool>
         <languageToolchain>XC8</languageToolchain>
         <languageToolchainVersion>2.45</languageToolchainVersion>
         <platform>2</platform>
diff --git a/prosjekt.X/uart.c b/prosjekt.X/uart.c
new file mode 100644
index 0000000..67648d1
--- /dev/null
+++ b/prosjekt.X/uart.c
@@ -0,0 +1,25 @@
+
+#include "uart.h"
+
+void init_uart(uint16_t baud) {
+    // Configure UART pin directions
+    PORTB.DIR &= ~PIN1_bm;
+    PORTB.DIR |= PIN0_bm;
+    // Set the baudrate
+    USART3.BAUD = (uint16_t)USART3_BAUD_RATE(baud);
+    // Enable UART TX & RX
+    USART3.CTRLB |= USART_TXEN_bm;
+}
+
+void USART3_sendChar(char c) {
+    // Hold the code while the UART is not ready to send
+    while (!(USART3.STATUS & USART_DREIF_bm)) { ; }
+    // UART is ready, send the character.
+    USART3.TXDATAL = c;
+
+}
+
+int USART3_printChar(char c, FILE *stream) {
+    USART3_sendChar(c);
+    return 0;
+}
\ No newline at end of file
diff --git a/prosjekt.X/uart.h b/prosjekt.X/uart.h
new file mode 100644
index 0000000..6259eee
--- /dev/null
+++ b/prosjekt.X/uart.h
@@ -0,0 +1,35 @@
+/* 
+ * File:   uart.h
+ * Author: Sebastian H. Gabrielli
+ *
+ * Created on March 6, 2024, 3:19 PM
+ */
+
+#ifndef UART_H
+#define	UART_H
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+#include <avr/io.h>
+#include <stdio.h>
+
+#ifndef F_CPU
+    #define F_CPU 4E6
+#endif
+    
+#define USART3_BAUD_RATE(BAUD_RATE) ((float)(F_CPU * 64 / (16 * (float)BAUD_RATE)) + 0.5)
+    
+void init_uart(uint16_t baud);
+void USART3_sendChar(char c);
+int USART3_printChar(char c, FILE *stream);
+
+static FILE USART_stream = FDEV_SETUP_STREAM(USART3_printChar, NULL, _FDEV_SETUP_WRITE);
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* UART_H */
+

From 7dd8b67378f74c1834ec0da7b3572298d1450869 Mon Sep 17 00:00:00 2001
From: "Sebastian H. Gabrielli" <gabrielli@sebaweb.no>
Date: Wed, 6 Mar 2024 15:55:56 +0100
Subject: [PATCH 2/2] Add comments

---
 prosjekt.X/uart.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/prosjekt.X/uart.h b/prosjekt.X/uart.h
index 6259eee..7284552 100644
--- a/prosjekt.X/uart.h
+++ b/prosjekt.X/uart.h
@@ -20,9 +20,14 @@ extern "C" {
 #endif
     
 #define USART3_BAUD_RATE(BAUD_RATE) ((float)(F_CPU * 64 / (16 * (float)BAUD_RATE)) + 0.5)
-    
+
+// Initialize the USART3 controller
 void init_uart(uint16_t baud);
+
+// Send a single character over UART
 void USART3_sendChar(char c);
+
+// Send a string of characters over UART
 int USART3_printChar(char c, FILE *stream);
 
 static FILE USART_stream = FDEV_SETUP_STREAM(USART3_printChar, NULL, _FDEV_SETUP_WRITE);