Add data receiving capabilities using a buffer with overflow protection

2025-10-04 15:12:25 +02:00
parent 40a5ad5a35
commit 6c48ebb65f
3 changed files with 77 additions and 6 deletions
@@ -0,0 +1,58 @@
+#include <stdint.h>
+#include <avr/io.h>
+#include "config.h"
+
+#define BUFFER_SIZE 8
+
+static inline void twiReset(void) {
+    // Enable TWI; enable ACK; clear interrupt flag; enable twi external interrupt
+    TWCR = (1 << TWEN) | (1 << TWEA) | (1 << TWINT) | (1 << TWIE);
+}
+
+void twiInit(void) {
+    TWAR = TWI_ADDR; //address definition found in config.h
+    twiReset();
+}
+
+static inline void twiSendAck(void) {
+    TWCR = (1 << TWEA) | (1 << TWINT);
+}
+
+static inline void twiSendNack(void) {
+    TWCR = (TWCR & ~(1 << TWEA)) | (1 << TWINT);
+}
+
+static void twiRespond(int8_t response[]) {
+    // Respond to TWI requests
+}
+
+
+static void twiExecute(int8_t buffer[]) {
+    // Perform actions based on received message
+    // if needed:
+    // twiRespond();
+}
+
+void twiAlert(void) {
+    static int8_t twiBuffer[BUFFER_SIZE] = {0};
+    static uint8_t bufferIndex = 0;
+
+    switch (TWSR & 0xF8) {
+        case 0x60: // SLA+W received
+            twiSendAck();
+            break;
+        case 0x80: // data received
+            if(bufferIndex < BUFFER_SIZE) {
+                twiBuffer[bufferIndex++] = TWDR;
+                twiSendAck();
+            } else twiSendNack();
+            break;
+        case 0xA0: // stop condition
+            twiExecute(twiBuffer);
+            twiReset();
+            break;
+        default:
+            twiSendNack();
+            break;
+    }
+}