This process is used to verify the signals, buses, electrical connections and timing between the host (control processor), UART and printed circuit board. The execution and verification of the following processes do not require any other test equipment (logic analyzer, protocol analyzer, oscilloscope, etc.), it is based on the assumption that the processor can read and write UART and the results can be displayed to the operator. If it is not possible to completely confirm that the simple read and write operations are executed correctly, then other checks on the UART connection are unreliable.
This application note explains a step‑by‑step verification flow for the AN462 UART, covering register write/read operations, status‑register checks, and a local loop‑back mode to confirm correct signal, bus, and timing behavior between the host processor and the PCB.
The procedure requires only the UART, its connection to the control/display device, and no external logic analyzers or oscilloscopes. It details hardware reset, MR register programming, command‑register writes, and status‑register interpretation to detect hardware or software errors. This manual is written in Chinese.
| Baud rate | 9600 bps |
|---|---|
| MR0 default value | 0x00 |
| MR1 default value | 0x13 |
| MR2 default value | 0x00 |
| Command register value to enable transmitter | 0x15 |
The status register returns 0x0C, showing the transmitter is ready and its FIFO is empty.
The example uses a baud rate of 9600 bps.
Execute a hardware reset; if a reset pin is unavailable, manually disconnect the reset pin to generate a temporary hardware reset.