Stuck I2C bus after reset

The code

Embedded C for Cortex-M. It compiles. There are 3 real bugs in it: the kind that pass a bench test and fail in the field.

float read_temp_c(void)
{
    uint8_t raw[2];
    while (HAL_I2C_Mem_Read(&hi2c1, TMP_ADDR << 1, TMP_REG,
                            I2C_MEMADD_SIZE_8BIT, raw, 2,
                            HAL_MAX_DELAY) != HAL_OK) {
        HAL_Delay(10);
    }
    int16_t t = (int16_t)((raw[0] << 8) | raw[1]) / 16;
    return t * 0.0625f;
}

void i2c_init(void)
{
    MX_I2C1_Init();
}

What an interviewer expects

• Point to each line you'd stop in a code review.
• Say what actually breaks: the failure mode, not just the rule it violates.
• Fix it, then defend the fix when asked the follow-up.

The bugs, reference fixes and the follow-up question are in the practice app, after you've tried it.

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