MSPM0G1505: Can`t get the latest TX data from I2C

Tool/software:

Dear Ti teams,

I want to get some info from MSPM0G1505 through I2C.

Now I can successfully get the response from MSPM0G1505, but it seems I got the last time TX buffer.

For example, I send 0x1, I want to receive 0x1, but I receive 0x00 the first time, unless I send 0x1 again, then I receive 0x1.

Then, I send 0x2, I hope to receive 0x2 0x1 the first time, but I still receive 0x1, unless I send it again.

The same issue occurs when sending 0x1 0x2, it seems I always get the TX buffer from the last time. I want to know why and how to optimize my code.

I have uploaded the logs and some key parts of the code. Could you help to review if there are any issues?

void I2C_0_INST_IRQHandler(void)
{
    static bool dataRx = false;

    switch (DL_I2C_getPendingInterrupt(I2C_0_INST))
    {
        case DL_I2C_IIDX_TARGET_START:
            // Initialize RX or TX after Start condition is received
            //gTxCount = 0;
            gRxCount = 0;
            // Flush TX FIFO to refill it
            //DL_I2C_flushTargetTXFIFO(I2C_0_INST);
            break;
        case DL_I2C_IIDX_TARGET_RXFIFO_TRIGGER:
            // Store received data in buffer
            dataRx = true;
            while (DL_I2C_isTargetRXFIFOEmpty(I2C_0_INST) != true)
            {
                uint8_t receivedData = DL_I2C_receiveTargetData(I2C_0_INST);
                if (gRxCount < gRxLen)
                {
                    gRxPacket[gRxCount++] = receivedData;
                }
                else
                {
                    DL_I2C_receiveTargetData(I2C_0_INST);
                }

            }
            break;
        case DL_I2C_IIDX_TARGET_TXFIFO_TRIGGER:
            //  Fill TX FIFO if there are more bytes to send
            if (gTxCount < gTxLen)
            {
                //gTxCount += DL_I2C_fillTargetTXFIFO(I2C_0_INST, gTxPacket, gTxLen);
                gTxCount += DL_I2C_fillTargetTXFIFO(I2C_0_INST, &gTxPacket[gTxCount], (gTxLen - gTxCount));
            }
            else
            {
                //
                // Fill FIFO with 0x00 if more data is requested than
                // expected gTxLen
                //
                while (DL_I2C_transmitTargetDataCheck(I2C_0_INST, 0x00) != false);
            }
            break;
        case DL_I2C_IIDX_TARGET_STOP:
            //  If data was received, echo to TX buffer
            if (dataRx == true)
            {
                if(gRxPacket[0] == 0x1)
                {
                    if(gRxPacket[1] == 0x2)
                    {
                        gTxPacket[0] = 0xf;
                        gTxPacket[1] = 0x4;
                        gTxLen = 2;
                        DL_I2C_flushTargetTXFIFO(I2C_0_INST);
                    }
                    else 
                    {
                        gTxPacket[0] = 0x1;
                        gTxLen = 1;
                        DL_I2C_flushTargetTXFIFO(I2C_0_INST);
                    }
                }


                if(gRxPacket[0] == 0x2)
                {
                    gTxPacket[0] = 0x2;
                    gTxPacket[1] = 0x1;
                    gTxLen = 2;
                    DL_I2C_flushTargetTXFIFO(I2C_0_INST);
                }

                if(gRxPacket[0] == 0x3)
                {
                    uint16_t temp_vgs1 = 500; //500 = -3.87V
                    DL_Timer_setCaptureCompareValue(PWM_1_INST, temp_vgs1, GPIO_PWM_1_C1_IDX);    //PWM_Vgs_PA0(10)  Vgs-PA0
                    DL_Timer_setCaptureCompareValue(PWM_2_INST, temp_vgs1, GPIO_PWM_2_C0_IDX);    //PWM_Vgs_PA1(11)  Vgs-PA1
                    DL_Timer_setCaptureCompareValue(PWM_0_INST, temp_vgs1, GPIO_PWM_0_C3_IDX);    //PWM_Vgs_PA2(14)  Vgs-PA2
                    DL_Timer_setCaptureCompareValue(PWM_0_INST, temp_vgs1, GPIO_PWM_0_C1_IDX);
                    gTxPacket[0] = 0x6;
                    gTxLen = 1;
                }

                //DL_I2C_flushTargetTXFIFO(I2C_0_INST);
                gTxCount = 0;
                dataRx = false;
                //cleanRxPacket();
            }
            //  Toggle LED to indicate successful RX or TX
            //  DL_GPIO_togglePins(GPIO_LEDS_PORT, GPIO_LEDS_USER_LED_1_PIN);
            break;
        case DL_I2C_IIDX_TARGET_RX_DONE:
            //  Not used for this example
        case DL_I2C_IIDX_TARGET_RXFIFO_FULL:
            //  Not used for this example
        case DL_I2C_IIDX_TARGET_GENERAL_CALL:
            //  Not used for this example
        case DL_I2C_IIDX_TARGET_EVENT1_DMA_DONE:
            //  Not used for this example
        case DL_I2C_IIDX_TARGET_EVENT2_DMA_DONE:
            //  Not used for this example
        default:
            break;
    }