I2C tested, main file now contains rough sample for use with DHT20

SHAL/Include/Core/SHAL_CORE.h

@@ -22,6 +22,16 @@ void SHAL_init();
 
 //Universal structs and defines ---------------------------
 
+typedef bool (*condition_fn_t)(void);
+
+#define SHAL_WAIT_FOR_CONDITION_US(cond, timeout_us) \
+    SHAL_wait_for_condition_us([&](){ return (cond); }, (timeout_us))
+
+#define SHAL_WAIT_FOR_CONDITION_MS(cond, timeout_ms) \
+    SHAL_wait_for_condition_ms([&](){ return (cond); }, (timeout_ms))
+
+
+
 //Currently configures systick to count down in microseconds
 void systick_init();
 
@@ -30,6 +40,28 @@ void SHAL_delay_us(uint32_t us);
 
 void SHAL_delay_ms(uint32_t ms);
 
+template<typename Condition>
+bool SHAL_wait_for_condition_us(Condition cond, uint32_t timeout_us) {
+    while (timeout_us--) {
+        if (cond()) {
+            return true; // success
+        }
+        SHAL_delay_us(1);
+    }
+    return false; // timeout
+}
+
+template<typename Condition>
+bool SHAL_wait_for_condition_ms(Condition cond, uint32_t timeout_ms) {
+    while (timeout_ms--) {
+        if (cond()) {
+            return true; // success
+        }
+        SHAL_delay_ms(1);
+    }
+    return false; // timeout
+}
+
 //---------------------------------------------------------
 
 

SHAL/Include/Peripheral/I2C/SHAL_I2C.h

@@ -27,6 +27,8 @@ public:
     /// \param readLen number of bytes to be read
     void masterWriteRead(uint8_t addr,const uint8_t* writeData, size_t writeLen, uint8_t* readData, size_t readLen);
 
+    uint8_t masterWriteReadByte(uint8_t addr, const uint8_t* writeData, size_t writeLen);
+
     /// Function to write an array of commands to an I2C device
     /// \param addr Address of slave device
     /// \param writeData Pointer to array of commands

SHAL/Src/Core/SHAL_CORE.cpp

@@ -10,18 +10,29 @@ void SHAL_init(){
 
 
 void systick_init(){
-    SysTick->CTRL = 0;           //disable first
-    SysTick->LOAD = 0xFFFFFF;    //max 24-bit
-    SysTick->VAL  = 0;           //clear
+    SysTick->CTRL = 0;           //Disable first
+    SysTick->LOAD = 0xFFFFFF;    //Max 24-bit
+    SysTick->VAL  = 0;           //Clear
     SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk | SysTick_CTRL_ENABLE_Msk;
 }
 
-void SHAL_delay_us(uint32_t us){
-    uint32_t start = SysTick->VAL;
-    uint32_t ticks = us * (SystemCoreClock / 1000000U);
 
-    //handle wraparound with 24-bit mask
-    while (((start - SysTick->VAL) & 0x00FFFFFF) < ticks) { }
+void SHAL_delay_us(uint32_t us){
+    uint32_t ticks = us * (SystemCoreClock / 1000000U);
+    uint32_t start = SysTick->VAL;
+
+    //Calculate target value (may wrap around)
+    uint32_t target = (start >= ticks) ? (start - ticks) : (start + 0x01000000 - ticks);
+    target &= 0x00FFFFFF;
+
+    //Wait until we reach the target
+    if (start >= ticks) {
+        //No wraparound case
+        while (SysTick->VAL > target) {}
+    } else {
+        while (SysTick->VAL <= start) {} //Wait for wraparound
+        while (SysTick->VAL > target) {} //Wait for target
+    }
 }
 
 void SHAL_delay_ms(uint32_t ms){

SHAL/Src/Peripheral/I2C/SHAL_I2C.cpp

@@ -5,15 +5,21 @@
 #include "SHAL_I2C.h"
 #include "SHAL_GPIO.h"
 
+#include "SHAL_UART.h"
+
 void SHAL_I2C::init(I2C_Pair pair) volatile {
     m_I2CPair = pair;
 
-    SHAL_I2C_Pair I2CPair = getI2CPair(pair); //Get the UART_PAIR information to be initialized
+    SHAL_I2C_Pair I2CPair = getI2CPair(pair); //Get the I2C_PAIR information to be initialized
 
     //Get the SHAL_GPIO pins for this SHAL_I2C setup
     GPIO_Key SCL_Key = I2CPair.SCL_Key; //SCL pin
     GPIO_Key SDA_Key = I2CPair.SDA_Key; //SDA pin
 
+    SHAL_I2C_Enable_Reg pairI2CEnable = getI2CEnableReg(pair); //Register and mask to enable the I2C peripheral
+
+    *pairI2CEnable.reg &= ~pairI2CEnable.mask; //Enable I2C peripheral clock
+
     GET_GPIO(SCL_Key).setPinMode(PinMode::ALTERNATE_FUNCTION_MODE); //Implicitly initializes and enables GPIO bus
     GET_GPIO(SDA_Key).setPinMode(PinMode::ALTERNATE_FUNCTION_MODE);
 
@@ -30,13 +36,12 @@ void SHAL_I2C::init(I2C_Pair pair) volatile {
     GET_GPIO(SCL_Key).setInternalResistor(InternalResistorType::PULLUP);
     GET_GPIO(SDA_Key).setInternalResistor(InternalResistorType::PULLUP);
 
-    SHAL_I2C_Enable_Reg pairI2CEnable = getI2CEnableReg(pair); //Register and mask to enable the I2C peripheral
     SHAL_I2C_Reset_Reg pairI2CReset = getI2CResetReg(pair);
 
-    *pairI2CReset.reg |= pairI2CReset.mask; //Reset peripheral
     *pairI2CEnable.reg |= pairI2CEnable.mask; //Enable I2C peripheral clock
 
-    I2CPair.I2CReg->CR1 |= I2C_CR1_PE; //Enable I2C peripheral
+    *pairI2CReset.reg |= pairI2CReset.mask; //Reset peripheral
+    *pairI2CReset.reg &= ~pairI2CReset.mask; //Reset peripheral
 }
 
 void SHAL_I2C::setClockConfig(uint8_t prescaler, uint8_t dataSetupTime, uint8_t dataHoldTime, uint8_t SCLHighPeriod, uint8_t SCLLowPeriod) {
@@ -48,46 +53,68 @@ void SHAL_I2C::setClockConfig(uint8_t prescaler, uint8_t dataSetupTime, uint8_t
     *clockReg.reg |= (dataHoldTime << clockReg.dataHoldTime_offset);
     *clockReg.reg |= (SCLHighPeriod << clockReg.SCLHighPeriod_offset);
     *clockReg.reg |= (SCLLowPeriod << clockReg.SCLLowPeriod_offset);
+
+    getI2CPair(m_I2CPair).I2CReg->CR1 |= I2C_CR1_PE; //Enable I2C peripheral
 }
 
 void SHAL_I2C::setClockConfig(uint32_t configuration) {
     *getI2CTimerReg(m_I2CPair).reg = configuration;
+
+    getI2CPair(m_I2CPair).I2CReg->CR1 |= I2C_CR1_PE; //Enable I2C peripheral
 }
 
 void SHAL_I2C::masterWriteRead(uint8_t addr,const uint8_t* writeData, size_t writeLen, uint8_t* readData, size_t readLen) {
+
     volatile I2C_TypeDef* I2CPeripheral = getI2CPair(m_I2CPair).I2CReg;
 
-    //Wait for I2C  bus
-    while (I2CPeripheral->ISR & I2C_ISR_BUSY);
+    if(!SHAL_WAIT_FOR_CONDITION_MS((I2CPeripheral->ISR & I2C_ISR_BUSY) == 0, 100)){
+        SHAL_UART2.sendString("I2C timed out waiting for not busy\r\n");
+        return;
+    }
 
     //Write phase
     if (writeLen > 0) {
         //Configure: NBYTES = wlen, write mode, START
-        I2CPeripheral->CR2 = (addr << 1) |
-                             (writeLen << I2C_CR2_NBYTES_Pos) |
-                             I2C_CR2_START;
+        I2CPeripheral->CR2 = (addr << 1) | (writeLen << I2C_CR2_NBYTES_Pos) | I2C_CR2_START;
 
         for (size_t i = 0; i < writeLen; i++) {
-            while (!(I2CPeripheral->ISR & I2C_ISR_TXIS)); // TX ready
+            if(!SHAL_WAIT_FOR_CONDITION_MS((I2CPeripheral->ISR & I2C_ISR_TXIS) != 0, 100)){
+                SHAL_UART2.sendString("I2C timed out waiting for TX\r\n");
+                return;
+            }
             I2CPeripheral->TXDR = writeData[i];
         }
 
         //Wait until transfer complete
-        while (!(I2CPeripheral->ISR & I2C_ISR_TC));
+        if(!SHAL_WAIT_FOR_CONDITION_MS((I2CPeripheral->ISR & I2C_ISR_TC) != 0, 100)){
+            SHAL_UART2.sendString("I2C timed out waiting for TC\r\n");
+            return;
+        }
     }
 
     //Read phase
     if (readLen > 0) {
-        I2CPeripheral->CR2 = (addr << 1) |
+
+        SHAL_UART2.sendString("Read initiated\r\n");
+
+        I2CPeripheral->CR2 &= ~(I2C_CR2_NBYTES | I2C_CR2_SADD | I2C_CR2_RD_WRN);
+        I2CPeripheral->CR2 |= (addr << 1) |
                               I2C_CR2_RD_WRN |
                               (readLen << I2C_CR2_NBYTES_Pos) |
                               I2C_CR2_START | I2C_CR2_AUTOEND;
 
         for (size_t i = 0; i < readLen; i++) {
-            while (!(I2CPeripheral->ISR & I2C_ISR_RXNE)); //RX ready
+            if(!SHAL_WAIT_FOR_CONDITION_MS((I2CPeripheral->ISR & I2C_ISR_RXNE) != 0 , 100)){
+                SHAL_UART2.sendString("I2C timed out waiting for RXNE\r\n");
+                return;
+            }
+            SHAL_UART2.sendString("Read byte");
             readData[i] = static_cast<uint8_t>(I2CPeripheral->RXDR);
         }
     }
+    else{
+        I2CPeripheral->CR2 |= I2C_CR2_STOP;
+    }
 }
 
 void SHAL_I2C::masterWrite(uint8_t addr, const uint8_t *writeData, uint8_t writeLen) {
@@ -98,6 +125,12 @@ void SHAL_I2C::masterRead(uint8_t addr, uint8_t *readBuffer, uint8_t bytesToRead
     masterWriteRead(addr,nullptr,0,readBuffer,bytesToRead);
 }
 
+uint8_t SHAL_I2C::masterWriteReadByte(uint8_t addr, const uint8_t *writeData, size_t writeLen) {
+    uint8_t val = 0;
+    masterWriteRead(addr, writeData, writeLen, &val, 1);
+    return val;
+}
+
 SHAL_I2C& I2CManager::get(uint8_t I2CBus) {
 
     if(I2CBus > NUM_I2C_BUSES - 1){

SHAL/Src/main.cpp

@@ -1,10 +1,44 @@
 #include "SHAL.h"
 #include "stm32f0xx.h"
 
+#include <stdlib.h>
 
 void c3Interrupt(){
-    PIN(A5).toggle();
-    UART(2).sendString("New test");
+    SHAL_UART2.sendString("Begin\r\n");
+
+    uint8_t cmd[3] = {0xAC, 0x33, 0x00};
+    SHAL_I2C1.masterWrite(0x38, cmd, 3);
+
+    SHAL_delay_ms(100);
+
+    uint8_t dht_buf[7] = {0};
+
+    //Read 7 bytes (status + 5 data + CRC)
+    SHAL_I2C1.masterRead(0x38, dht_buf, 7);
+
+    //Parse humidity (20 bits)
+    uint32_t rawHumidity = ((uint32_t)dht_buf[1] << 12) |
+                           ((uint32_t)dht_buf[2] << 4) |
+                           ((uint32_t)dht_buf[3] >> 4);
+
+    uint32_t rawTemp = (((uint32_t)dht_buf[3] & 0x0F) << 16) |
+                       ((uint32_t)dht_buf[4] << 8) |
+                       ((uint32_t)dht_buf[5]);
+
+    // Use 64-bit intermediate to avoid overflow
+    uint32_t hum_hundredths = (uint32_t)(((uint64_t)rawHumidity * 10000ULL) >> 20);
+    int32_t temp_hundredths = (int32_t)((((uint64_t)rawTemp * 20000ULL) >> 20) - 5000);
+
+    char out[80];
+    sprintf(out, "rawH=0x%05lX rawT=0x%05lX\r\n",
+            (unsigned long)rawHumidity, (unsigned long)rawTemp);
+    SHAL_UART2.sendString(out);
+
+    // print as X.YY
+    sprintf(out, "Temp: %ld.%02ld C, Hum: %ld.%02ld %%\r\n",
+            (long)(temp_hundredths / 100), (long)(abs(temp_hundredths % 100)),
+            (long)(hum_hundredths / 100), (long)(hum_hundredths % 100));
+    SHAL_UART2.sendString(out);
 }
 
 void tim2Handler(){
@@ -20,6 +54,7 @@ int main() {
     SHAL_UART2.begin(115200);
 
     SHAL_I2C1.init(I2C_Pair::SCL1B6_SDA1B7);
+    SHAL_I2C1.setClockConfig(0x2000090E);
 
     //Use pin C3 to trigger a function on external interrupt
     PIN(C3).useAsExternalInterrupt(TriggerMode::RISING_EDGE,c3Interrupt);
@@ -31,11 +66,24 @@ int main() {
     PIN(A4).setPinMode(PinMode::OUTPUT_MODE);
     PIN(A5).setPinMode(PinMode::OUTPUT_MODE);
 
+
+
+    SHAL_delay_ms(3000); //Wait 100 ms from datasheet
+
+    uint8_t cmd = 0x71;
+    uint8_t status = 0;
+
+    SHAL_I2C1.masterWriteRead(0x38, &cmd, 1, &status, 1);
+
+    char statusString[32];
+    sprintf(statusString, "Status = 0x%02X\r\n", status);
+    SHAL_UART2.sendString(statusString);
+
+
+    SHAL_delay_ms(10);
+
     c3Interrupt();
-
-    SHAL_delay_ms(3000);
-
-    c3Interrupt(); //test
+    //End setup
 
     while (true) {
     	__WFI();