I'm using PMM240 power management board to control battery RRC-2054, and I have problem to use SMBus, please see the code I listed below, looks device is ready, but when you send something, it is always in busy(Master Data Transmission process is ongoing). Will this a matter of address problem, or a command problem, or others? anyway to get more info for this busy status?

if (HAL_SMBUS_IsDeviceReady(&hsmbus2, (uint16_t) PMM240_ADDRESS, 2, 2)
            != HAL_OK) {
uint32_t test = HAL_SMBUS_GetState(&hsmbus2);
        if (test != HAL_SMBUS_STATE_READY) {
        ret = HAL_SMBUS_Master_Transmit_IT(&hsmbus2,
                (uint16_t) PMM240_ADDRESS, &buffertx[0], 1,

        if (ret != HAL_OK) {
        // after enough time delay, 100 or 1000 ms
          HAL_Delay(100);//not useful for the following code.
       // inserting HAL_SMBUS_Init(&hsmbus2) could reset the busy status, but info lost, right?
        test = HAL_SMBUS_GetState(&hsmbus2);
        if (test != HAL_SMBUS_STATE_READY) {
            Error_Handler();//not passed
  • \$\begingroup\$ Where are you waiting/testing for the SMBus operation to complete? Of course it is busy right after you start it. Or is that not the complete code? Which STM32 this is? \$\endgroup\$
    – Justme
    Commented Jun 25, 2019 at 19:56
  • \$\begingroup\$ "// after enough time delay in debug mode" so I just run step by step and there are a few seconds delay between each command, I am runing stm32cubeMX on L476RG \$\endgroup\$
    – adam
    Commented Jun 25, 2019 at 21:46

1 Answer 1


I am sure that the function HAL_SMBUS_IsDeviceReady() is not working correctly. I used a different solution to search for devices on the bus. Maybe this will be useful.

// produce Start 
HAL_result = HAL_SMBUS_Master_Transmit_IT(hsmbus, CheckingAddress, &value, 0, SMBUS_FIRST_FRAME);
//HAL_result = HAL_SMBUS_IsDeviceReady(hsmbus, CheckingAddress, 3, 100);
//while(HAL_SMBUS_GetState(hsmbus) != HAL_SMBUS_STATE_READY); // work without this line
if ( HAL_result == HAL_OK)
    //device is ready to connect
// finish transaction (may be not needed)
HAL_result = HAL_SMBUS_Master_Transmit_IT(hsmbus, CheckingAddress, &value, 0, SMBUS_LAST_FRAME_NO_PEC); 

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