static void keypad_pcf8574_write(keypad_t *s, uint8_t data){
    s->iostate=data;
    uint8_t error;
    vTaskSuspendAll();
    error = HAL_I2C_Master_Transmit(s->hi2c, (uint16_t)s->addr, &s->iostate, 1, 100);
    xTaskResumeAll();
    (void)error;
#if DEBUG
    dbg("write error code = %d\n\r",error);
#endif

    // hardfix busy flag hardware problem,
    // STM32F10xxC/D/E Errata sheet - page 23
    if(error!=0){       // WARNING!!!
        HAL_I2C_DeInit(s->hi2c);        // I2C RESET WHEN BUS FAULT, ITS WORKING ON F103
        MX_I2C1_Init();
#if DEBUG
        dbg("restart i2c\n\r");
#endif
    }

}