# Firmware Update

The board contains two MCUs. Each chip manages two CAN/CAN FD and two RS485
interfaces, so both chips must be programmed separately.

## Firmware Download

Download the latest [STM32G0B1 V82 release package](https://gitcode.com/sanpo/robot/blob/main/products/spine/v8/firmware/g0b/release/spine_v8_v82_g0b_release.zip). After extracting it, program `spine_v8_v82_g0b_release.bin` and verify its integrity with the SHA-256 file in the same directory.

## Important Warning

**Do not perform a full-chip erase.** High Flash addresses may store device
identity, authorization information, communication settings, and offline batch
tasks. A full-chip erase deletes this data, and a normal firmware image cannot
restore it automatically.

Download the firmware starting at `0x08000000`. Use **Download & Verify** or
**Program & Verify**. Do not select a full-chip erase.

## Update with STM32CubeProgrammer

Prepare an ST-LINK, STM32CubeProgrammer, and the selected release firmware, then
follow these steps:

1. Power the board through USB and ensure the voltage is at least 5 V.
2. Connect ST-LINK to the SWD connector of the first MCU.
3. Select `ST-LINK` in STM32CubeProgrammer and connect.
4. Select the `*_release.bin` file in the release directory and set the download
   address to `0x08000000`.
5. Download and verify directly; do not erase the full chip first.
6. Disconnect ST-LINK, connect it to the second MCU's SWD connector, and repeat
   steps 3-5.
7. Power-cycle the board.

## Check the Board After Updating

Open the USB management serial port for each MCU. Windows normally displays it
as `SANPO Studio Management Port`. Send:

```text
AT+VER
```

Use `CRLF` as the line ending. The response should match the firmware just
programmed, for example:

```text
V82
```

Then query the communication settings:

```text
AT+SETFDCAN?
AT+SETRS485?
AT+SPIMODE?
AT+RS485RAWCH?
AT+BATAUTO?
```

An update normally preserves existing communication settings, so the values
may differ from the factory defaults. If you need to restore communication
defaults, send `AT+CFGERASE` only after confirming that it is appropriate for
the installed firmware.

## Factory Communication Defaults

| Item | Default |
| --- | --- |
| Classic CAN / CAN FD arbitration phase | 1 Mbit/s |
| CAN FD data phase | 5 Mbit/s, BRS enabled |
| RS485 | 4 Mbit/s, 1 stop bit, no parity, 8 data bits |
| SPI | `SHORT`, 23 bytes per transfer |

When the SPI host needs CAN FD, send:

```text
AT+SPIMODE=LONG
```