Get Started

The SANPO robot integration board connects a PC or host controller to CAN, CAN FD, and RS485 joint motors. V6 lets USB serial, Linux SocketCAN, or SPI control the board’s four CAN/CAN FD and four RS485 interfaces.

This document applies to the FDCAN upgraded board shipped with V6 firmware. For V4 Standard, CAN-isolated, or RS485-isolated boards, see the V4 documentation.

On This Page

• Product Overview

• Choose a Host Interface

• Default Communication Settings

• Channel Numbering

• USB Access

• SPI Access

• Configuration and Maintenance

Product Overview

Item	Description
Host interfaces	USB serial / Linux SocketCAN / SPI
Motor interfaces	4 × CAN/CAN FD + 4 × RS485
CAN data length	Classic CAN: up to 8 bytes; CAN FD: up to 64 bytes
SPI mode	SHORT: 23 bytes; LONG: 73 bytes
Offline execution	Store and automatically execute CAN, CAN FD, and RS485 commands
Expansion	I2C / ADC / UART / SWD

Each MCU controls two CAN/CAN FD and two RS485 interfaces and is accessed through its own USB port and SPI chip select. Both MCUs use the same firmware; only the physical interface numbers differ.

Choose a Host Interface

Use case	Documentation
Control CAN or CAN FD from Linux through canX	SocketCAN
Send raw RS485 data directly; leave at least 3 ms of idle time between commands, or use the SANPO protocol for continuous high-rate control	RS485 Raw Passthrough
Control a selected classic CAN channel through USB serial	SANPO USB to CAN
Control a selected CAN FD channel through USB serial	SANPO USB to FDCAN
Control a selected RS485 channel through USB serial	SANPO USB to RS485
Control classic CAN from a Jetson, Raspberry Pi, or another host through SPI	SANPO SPI to CAN
Control CAN FD from a Jetson, Raspberry Pi, or another host through SPI	SANPO SPI to FDCAN
Control RS485 from a Jetson, Raspberry Pi, or another host through SPI	SANPO SPI to RS485

SocketCAN uses the standard Linux CAN interface and does not require SANPO headers. USB serial and SPI extended protocols use these headers:

Header	Hex	Purpose
ST	53 54	Classic CAN standard frame
ET	45 54	Classic CAN extended frame
SF	53 46	CAN FD standard frame
EF	45 46	CAN FD extended frame
RT	52 54	Wrapped RS485 frame

Default Communication Settings

Item	Factory default
Classic CAN	1 Mbps
CAN FD arbitration phase	1 Mbps
CAN FD data phase	5 Mbps with BRS enabled
RS485	4 Mbps, one stop bit, no parity, eight data bits
SPI	SHORT, 23 bytes
USB RS485 replies	Wrapped RT; RAW replies disabled

USB serial and SPI use settings stored by the firmware. SocketCAN is configured separately by Linux with ip link. The “serial bitrate” selected in a USB terminal does not change CAN, CAN FD, or RS485 bus settings.

For first use or after changing motors, send these commands as text over USB serial with a CRLF line ending:

AT+VER
AT+SETFDCAN?
AT+SETRS485?
AT+SPIMODE?

The reply is the version of the installed firmware. For example, the G473 V66 release returns:

V66

See Communication Settings for configuration commands.

Channel Numbering

One USB serial connection or SPI chip select accesses the two buses managed by the current MCU. Transmit frames may use whole-board interface numbers, but the firmware selects a local interface as follows:

Channel	Target on the current MCU
0x01 or 0x03	First CAN/CAN FD/RS485 channel
0x02 or 0x04	Second CAN/CAN FD/RS485 channel
0x00	Both channels of the selected bus type

Use 1/2 with the first MCU and 3/4 with the second so the host configuration matches the CAN-1 to CAN-4 and RS485-1 to RS485-4 silkscreen.

Replies use the local Channel number: 0x01 for the first channel and 0x02 for the second. Feedback from CAN-3, CAN-4, RS485-3, or RS485-4 therefore also appears as 0x01 or 0x02 on the corresponding USB port or SPI chip select.

USB Access

A complete board normally exposes two USB serial ports. Linux also exposes four canX interfaces through gs_usb. COM, /dev/ttyACM*, and canX numbering does not necessarily follow board silkscreen order. For first use, connect only one motor and confirm the mapping.

• On Windows, use SANPO Studio, a serial application, or a tool supplied by the motor manufacturer.

• On Linux, use USB serial; for CAN/CAN FD you can also use can-utils or python-can directly.

• Before sending unwrapped RS485 data, enable RAW replies as described in RS485 Raw Passthrough.

SPI Access

SPI is suitable for periodic control from a Jetson, Raspberry Pi, or another host. Software CS0 and CS1 normally connect to the board’s two external chip-select inputs, one for each MCU.

• Use SPI Mode 0, MSB First.

• Factory default is SHORT: exactly 23 bytes per transfer.

• CAN FD or more than 18 bytes of RS485 data requires LONG: exactly 73 bytes per transfer.

• SPI is full duplex. Data read while sending a command may be an older cached reply or all zero; send additional empty frames of the same length to read later feedback.

Configuration and Maintenance

• Communication Settings: configure CAN, CAN FD, RS485, and SPI length mode.

• Offline Batch Execution: store and automatically execute a group of motor commands.

• Firmware Update: update both MCU devices with ST-LINK.

• Interfaces and Pinout: view bus, expansion, and MCU pins.

• Migrating from V4 to V6: update an existing V4 host application for V6.

Important: Do not perform a full-chip erase during firmware updates. It removes factory identification, saved communication settings, and offline batches, and factory initialization must then be performed again.