From ac78f33c981ef9f947897f7a48cbba4b29c4901a Mon Sep 17 00:00:00 2001
From: "Sebastian H. Gabrielli" <gabrielli@sebaweb.no>
Date: Wed, 6 Mar 2024 14:58:49 +0100
Subject: [PATCH] Create basic i2c skeleton with interrupts

I2C init function has been created.
Interrupts have been made for each I2C interrupt. Which interrupt does
what is currently unknown.

See #1
---
 prosjekt.X/i2c.c                        | 32 +++++++++++++++++++++++++
 prosjekt.X/i2c.h                        | 26 ++++++++++++++++++++
 prosjekt.X/nbproject/configurations.xml |  2 ++
 3 files changed, 60 insertions(+)
 create mode 100644 prosjekt.X/i2c.c
 create mode 100644 prosjekt.X/i2c.h

diff --git a/prosjekt.X/i2c.c b/prosjekt.X/i2c.c
new file mode 100644
index 0000000..6474273
--- /dev/null
+++ b/prosjekt.X/i2c.c
@@ -0,0 +1,32 @@
+#include "i2c.h"
+
+void init_i2c(void) {
+  // Initialize the control A register
+  TWI0.CTRLA = TWI_INPUTLVL_I2C_gc    // I2C voltage transition level
+               | TWI_SDASETUP_4CYC_gc // Four clock cycles setup time
+               | TWI_SDAHOLD_50NS_gc  // 50ns SDA hold time
+               | TWI_FMPEN_OFF_gc     // Standard SPI timing
+      ;
+
+  // The device's slave address
+  TWI0.SADDR = 0x42;
+
+  // Enable acting as a slave
+  TWI0.SCTRLA = TWI_DIEN_bm     // Enable data interrupt
+                | TWI_PIEN_bm   // Enable stop flag interrupt
+                | TWI_SMEN_bm   // Enable smart mode
+                | TWI_ENABLE_bm // Enable acting as a slave
+      ;
+}
+
+// TODO: Figure out which interrupt does what
+
+// Interrupt vector
+ISR(TWI0_TWIS_vect) {
+    asm('nop');
+}
+
+// Interrupt vector
+ISR(TWI0_TWIM_vect) {
+    asm('nop');
+}
\ No newline at end of file
diff --git a/prosjekt.X/i2c.h b/prosjekt.X/i2c.h
new file mode 100644
index 0000000..7330fd8
--- /dev/null
+++ b/prosjekt.X/i2c.h
@@ -0,0 +1,26 @@
+/*
+ * File:   i2c.h
+ * Author: sebgab
+ *
+ * Created on March 6, 2024, 1:53 PM
+ */
+
+#ifndef I2C_H
+#define I2C_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Include the IO for I2C
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+// Initialize the I2C bus
+void init_i2c(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* I2C_H */
diff --git a/prosjekt.X/nbproject/configurations.xml b/prosjekt.X/nbproject/configurations.xml
index 64209ae..e78921c 100644
--- a/prosjekt.X/nbproject/configurations.xml
+++ b/prosjekt.X/nbproject/configurations.xml
@@ -5,6 +5,7 @@
                    displayName="Header Files"
                    projectFiles="true">
       <itemPath>command-handler.h</itemPath>
+      <itemPath>i2c.h</itemPath>
     </logicalFolder>
     <logicalFolder name="LinkerScript"
                    displayName="Linker Files"
@@ -15,6 +16,7 @@
                    projectFiles="true">
       <itemPath>main.c</itemPath>
       <itemPath>command-handler.c</itemPath>
+      <itemPath>i2c.c</itemPath>
     </logicalFolder>
     <logicalFolder name="ExternalFiles"
                    displayName="Important Files"