Accelerometer readings make no sense

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.

void accel_decode(const uint8_t raw[6], float g[3])
{
    for (int i = 0; i < 3; i++) {
        uint16_t v = (uint16_t)(raw[2 * i] << 8 | raw[2 * i + 1]);
        int16_t s = v >> 4;
        g[i] = s * 0.001f;
    }
}

bool accel_read(float g[3])
{
    uint8_t raw[6];
    if (HAL_I2C_Mem_Read(&hi2c1, ACC_ADDR << 1, OUT_X_L, I2C_MEMADD_SIZE_8BIT,
                         raw, 6, 10) != HAL_OK) return false;
    accel_decode(raw, g);
    return true;
}

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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