RDK S100 CAN communication¶

This handbook follows the recorded course slides, including wiring, commands, measured results, and the scope of verification.

Source slides

Verify CAN from a robot reset to a physical MCU expansion-board loopback.

Two CAN paths, two kinds of evidence¶

Robot reset shows the application. MCU expansion loopback verifies the S100 physical CAN path.

USB-to-CAN¶

Run one official reset through the robot SDK.

MCU-CAN¶

Connect CAN6 transmit to CAN5 receive on the expansion board.

Measured Result¶

All 12 transmissions match in ID and eight-byte payload.

S100 CAN crosses the MCU expansion path¶

Acore¶

Official CAN HAL samples run in Linux user space.

MCU1¶

Firmware forwards IPC channels to CAN.

Expansion Board¶

An FPC links the main board and MCU interface board.

Transceivers¶

CAN5 and CAN6 expose physical differential buses.

From robot application to physical bus¶

RobotPose offset

USB-to-CANOfficial reset

MCU1running / alive

CAN6→CAN5Three-wire loop

12/12Frame match

S100 resets the robot¶

The test reuses the same robot_py SDK, existing motor configuration, and default pose without recalibration.

Visible Motion¶

The waist and multiple joints return from an offset pose.

Official Sequence¶

Initialize, read, reset, read again, and deinitialize.

Clean Exit¶

deinit returns not initialized and closes four CAN links.

Keep the two demonstrations distinct¶

Together they form the lesson evidence, but each uses different hardware.

Robot reset proves the S100, USB-to-CAN, SDK, and actuator chain can work
Waist feedback changes by about 43.2 degrees
One reset is not walking, dancing, or full-joint accuracy acceptance
The MCU expansion test is not connected to robot motors
CAN6-to-CAN5 physical loopback proves the expansion-board CAN path

MCU expansion-board CAN loopback¶

Connect CAN_H, CAN_L, and ground between CAN6 and CAN5, with one 120-ohm termination at each end.

RDK S100 MCU expansion board CAN wiring

CAN6 H/L/GND → CAN5 H/L/GND | two 120Ω terminations | 1 Mbps

How one frame crosses the full path¶

can_sendAcore sample

IPC ch6bypass 6

CAN6Physical TX

CAN5Physical RX

IPC ch4can_get output

Run copies of the official examples¶

The original slash app slash Can directory remains unchanged; code, configuration, and logs stay in the isolated project.

Receiver¶

sudo ./can_get
IPC instance 0 / channel 4
CAN5 RX

Start the receiver before transmitting.

Transmitter¶

sudo ./can_send bypass 6
CAN6 TX @ 1 Mbps

Send an eight-byte classic CAN frame with ID 0x131.

The terminal shows the physical loopback¶

One recording displays MCU state, transmitted frames, received frames, and final PASS.

Transmit¶

CAN6 sends twelve frames with ID 0x131.

Receive¶

CAN5 returns the identical eight-byte payload.

Judge¶

Report physical CAN PASS only after all 12 frames match.

S100 MCU-CAN measured result¶

Direction¶

CAN6 TX → CAN5 RX

Bitrate¶

1,000,000 bit/s

Frame¶

ID 0x131 / 8 bytes

Result¶

12 sent / 12 received / all matched

The test leaves a reproducible state¶

The expansion-board work stays in an isolated directory and does not rewrite the frozen project or services.

MCU1 uses the official S100 4.0.5 S100_MCU_DEBUG.elf
MCU1 reports running and alive during the test
Official samples are copied into new_project before building
No canhal_get or canhal_send process remains after testing
SSH stays enabled; networking and the original project remain unchanged

Check missing frames in order¶

Channel mapping, termination, and direction must match the current firmware.

Step 1

Confirm MCU1 is running and alive, then verify the official firmware version.

Step 2

Check CAN_H to CAN_H, CAN_L to CAN_L, and ground to ground.

Step 3

Use one 120-ohm termination at each end and configure 1 Mbps.

Step 4

The current firmware is verified with CAN6 transmitting and CAN5 receiving.

RDK S100 CAN verification complete¶

A robot application and MCU expansion-board loopback demonstrate the S100 CAN development path.

Visible Application¶

USB-to-CAN drives an official robot reset.

Complete Path¶

Acore, MCU, FPC, transceivers, and wires are exercised.

Reproducible Result¶

CAN6 to CAN5 matches 12 of 12 frames.