Simplify moisture value access and update header structure

firmware/atmega/include/config.h

@@ -51,4 +51,6 @@ inline void eeprom_init() {
     for (int i = 0; i < DICT_SIZE; i++) if (eepromRead(keys[i]) == 0) eepromWrite(keys[i], values[i]);
 }
 
+extern volatile uint16_t *pLastMoistureVal;
+
 #endif

firmware/atmega/include/globals.h

@@ -1,8 +0,0 @@
-#ifndef GLOBALS_H
-#define GLOBALS_H
-
-#include <stdint.h>
-
-const uint16_t* moisturePtr(void);
-
-#endif

firmware/atmega/include/twi.h

@@ -1,7 +1,9 @@
 #ifndef TWI_H
 #define TWI_H
 
+extern volatile uint16_t *pLastMoistureVal;
+
 void twiInit(void);
-void twiAlert(void);
+void twiListen(void);
 
 #endif

firmware/atmega/source/main.c

@@ -9,6 +9,9 @@
 #include "pump.h"
 #include "twi.h"
 
+volatile uint16_t lastMoistureVal = 0;
+volatile uint16_t *pLastMoistureVal = &lastMoistureVal;
+
 ISR(WDT_vect) {
     triggerMoistureRead();
 }
@@ -40,17 +43,14 @@ static void setup(void) {
     watchdogs();
 }
 
-static uint16_t lastMoistureVal = 0;
-
-// Encapsulate lastMoistureVal to read later from twi
-const uint16_t *moisturePtr(void) { return &lastMoistureVal; }
-
 int main(void) {
     setup();
 
+    pLastMoistureVal = &lastMoistureVal;
+
     while(true) {
         if (readSensors) {
-            lastMoistureVal = moistureRead();
+            *pLastMoistureVal = moistureRead();
             // nested if: (result outside range (see config.h)) {waterPlant()}
 
         }

firmware/atmega/source/twi.c

@@ -1,8 +1,8 @@
 #include <stdint.h>
 #include <avr/io.h>
 #include "config.h"
-#include "globals.h"
 #include "pump.h"
+#include "twi.h"
 
 #define BUFFER_SIZE 4
 
@@ -24,17 +24,21 @@ static inline void twiSendNack(void) {
     TWCR = (TWCR & ~(1 << TWEA)) | (1 << TWINT);
 }
 
-static void twiRespond(int8_t buffer[]) {
+static void twiSendData(uint8_t data) {
+    TWDR = data;
+    twiSendAck();
+}
+
+static void twiRespond(uint8_t buffer[]) {
     switch(buffer[0]) {
-        //TODO: simplify by using a more parametrized way go set and get data
         case 0x01: // Send moisture
-            twiRespond(*moisturePtr());
+            twiSendData(*pLastMoistureVal);
             break;
         case 0x02: // Get MOISTURE_MIN
-            twiRespond(eepromRead(MOISTURE_MIN));
+            twiSendData(eepromRead(MOISTURE_MIN));
             break;
         case 0x03: // Get MOISTURE_MAX
-            twiRespond(eepromRead(MOISTURE_MAX));
+            twiSendData(eepromRead(MOISTURE_MAX));
             break;
         case 0x04: // Set parameters
             eepromWrite(MOISTURE_MIN, buffer[1]);
@@ -43,7 +47,7 @@ static void twiRespond(int8_t buffer[]) {
             twiSendAck();
             break;
         case 0x05: // Get SENSOR_READINGS
-            twiRespond(eepromRead(SENSOR_READINGS));
+            twiSendData(eepromRead(SENSOR_READINGS));
             break;
         case 0x06: // Set SENSOR_READINGS
             eepromWrite(SENSOR_READINGS, buffer[1]);
@@ -73,7 +77,7 @@ void twiListen(void) {
             TODO: see comment on line 29
     */
 
-    static int8_t twiBuffer[BUFFER_SIZE] = {0};
+    static uint8_t twiBuffer[BUFFER_SIZE] = {0};
     static uint8_t bufferIndex = 0;
 
     switch (TWSR & 0xF8) {