charge_controller_target_mspm0L1304/src/interfaces/i2c_controller.c

/*
 * This file implements Hardware Abstraction Layer (HAL) to make the I2C
 * communication of MSPM0 SDK compatible with ADC (MCP3426/7/8) and DAC
 * (MCP34728)
 */
#include "src/interfaces/i2c_controller.h"
#include "ti/driverlib/dl_i2c.h"
#include "ti_msp_dl_config.h"
#include <stdio.h>

/*
static function is for implementing Data Hiding, access to the static function
is restricted to the file where they are declared const keyword for
'i2c_addr' and 'Data_length' makes the variable immutable. const uint8_t *
const Data: means the pointer to the variable and the value of Data is immutable
*/

I2CRxPackage controllerRxPackage;
I2CTxPackage controllerTxPackage;

static bool msp_i2c_write(uint8_t const i2c_addr) {
    // Flush any stale data in TX FIFO:
    DL_I2C_flushControllerTXFIFO(I2C_controller_INST);

    // **Check if the I2C bus is stuck before WRITE
    if (DL_I2C_getControllerStatus(I2C_controller_INST) &
        DL_I2C_CONTROLLER_STATUS_ERROR) {
#ifdef DEBUG_I2C_ERR
        printf("I2C Communication: Bus is stuck!\n");
#endif
        DL_I2C_resetControllerTransfer(I2C_controller_INST); 
        return false; 
    }
    
    // **Wait for I2C Bus to be Free**
    uint32_t n_cycles = 0;
    while ((DL_I2C_getControllerStatus(I2C_controller_INST) &
            DL_I2C_CONTROLLER_STATUS_BUSY_BUS) && n_cycles++ < MAX_I2C_WAIT_RX)
        ;
    if (n_cycles == MAX_I2C_WAIT_RX) {
        printf("Error in reading from I2C Bus: Bus is not getting ready before transmit start\n");
        DL_I2C_resetControllerTransfer(I2C_controller_INST); 
        return false;
    }

    // **Start I2C Write Transaction**
    DL_I2C_startControllerTransfer(I2C_controller_INST, i2c_addr,
                                  DL_I2C_CONTROLLER_DIRECTION_TX, controllerTxPackage.len);

    // **Load Configuration Byte into TX FIFO**
    DL_I2C_fillControllerTXFIFO(I2C_controller_INST, controllerTxPackage.packet, controllerTxPackage.len);
#ifdef DEBUG_I2C_TX
    for (uint8_t i = 0; i < controllerTxPackage.len; i++) {
        printf("Sending 0x%02X\n", controllerTxPackage.packet[i]);
    }
#endif

    n_cycles = 0;
    while ((DL_I2C_getControllerStatus(I2C_controller_INST) &
            DL_I2C_CONTROLLER_STATUS_BUSY_BUS) && n_cycles++ < MAX_I2C_WAIT_RX)
        ;
    if (n_cycles == MAX_I2C_WAIT_RX) {
        printf("Error in reading from I2C Bus: Bus is not getting ready after transmit data\n");
        DL_I2C_resetControllerTransfer(I2C_controller_INST); 
        return false;
    }
    
    // **Check if the target address is incorrect
    
    if (DL_I2C_getControllerStatus(I2C_controller_INST) & DL_I2C_CONTROLLER_STATUS_ADDR_ACK) {
#ifdef DEBUG_I2C_ERR
        printf("I2C Write Error: Target Address not acknowledged!\n");
#endif
      return false;
    }

    // **Check for any WRITE error
    if (DL_I2C_getControllerStatus(I2C_controller_INST) & DL_I2C_CONTROLLER_STATUS_ERROR) {
#ifdef DEBUG_I2C_ERR
        printf("I2C Write Error: Bus error after sending data.\n");
#endif
        return false;
    }

    return true;
}

static bool msp_i2c_read(uint8_t const i2c_addr) {

  
    // Flush any stale data in TX FIFO:
    DL_I2C_flushControllerRXFIFO(I2C_controller_INST);
    
    uint32_t n_cycles = 0;
    while ((DL_I2C_getControllerStatus(I2C_controller_INST) &
            DL_I2C_CONTROLLER_STATUS_BUSY_BUS) && n_cycles++ < MAX_I2C_WAIT_RX)
        ;
    if (n_cycles == MAX_I2C_WAIT_RX) {
        printf("Error in reading from I2C Bus: Bus is not getting ready before transmit start\n");
    }

    DL_I2C_startControllerTransfer(I2C_controller_INST, i2c_addr,
                                    DL_I2C_CONTROLLER_DIRECTION_RX, controllerRxPackage.len);

    n_cycles = 0;
    while ((DL_I2C_getControllerStatus(I2C_controller_INST) &
            DL_I2C_CONTROLLER_STATUS_BUSY_BUS) && n_cycles++ < MAX_I2C_WAIT_RX)
        ;
    if (n_cycles == MAX_I2C_WAIT_RX) {
        printf("Error in reading from I2C Bus: Bus is not getting ready after transmit start\n");
    }
        
    DL_I2C_enableInterrupt(I2C_controller_INST,
                            DL_I2C_INTERRUPT_CONTROLLER_RXFIFO_TRIGGER);
    
    
    return true;
}

/**
 * this function discovers on the i2c bus the devices from the address
 * to ensure all relevant bus participants are present
 */
 bool i2c_discover(uint8_t i2c_addr) {
    if (DL_I2C_getControllerStatus(I2C_controller_INST) & DL_I2C_CONTROLLER_STATUS_BUSY_BUS) {
        DL_I2C_disableController(I2C_controller_INST);  // Disable I2C
        DL_I2C_enableController(I2C_controller_INST);   // Re-enable I2C
    }
#ifdef DEBUG_I2C_TX
    printf("Scanning 0x%02X\n", i2c_addr);
#endif
    DL_I2C_startControllerTransfer(I2C_controller_INST, i2c_addr, DL_I2C_CONTROLLER_DIRECTION_RX, 1);
    delay_cycles(5000);
    uint32_t i2c_status = DL_I2C_getControllerStatus(I2C_controller_INST);
    bool found = !(DL_I2C_getControllerStatus(I2C_controller_INST) & DL_I2C_CONTROLLER_STATUS_ERROR);
    DL_I2C_disableController(I2C_controller_INST);
    DL_I2C_enableController(I2C_controller_INST);
    return found;
}

I2C_Interface i2c_hal = {
    .write = msp_i2c_write,
    .read = msp_i2c_read,
};