Roll Call

A mock SPI sensor is wired to SPI1, but the firmware never reads a valid identity back from it. Bring up the SPI peripheral and read the sensor's WHO_AM_I register so the controller can confirm the right part is on the bus.

The sensor uses the standard SPI register-access convention: the address byte carries the register number plus a direction bit, and the register contents are clocked back on a following transfer. The starter code provides the SPI1 register map and bit masks. You enable the peripheral clock, configure SPI1 as master, and run the read transaction.