# Command ID 0x08 on CAN Bus

**URL:** <https://discourse.odriverobotics.com/t/command-id-0x08-on-can-bus/14529>\
**Category:** ODrive S1 Support\
**Created:** [September 7, 2026, 1:34pm UTC](https://discourse.odriverobotics.com/t/command-id-0x08-on-can-bus/14529 "2026-09-07T13:34:37Z")\
**Posts on this page:** 10\
**Page:** 1

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**Author:** ![akshat\_joshi](https://discourse.odriverobotics.com/user_avatar/discourse.odriverobotics.com/akshat_joshi/32/7805_2.png) [@akshat\_joshi](https://discourse.odriverobotics.com/u/akshat_joshi)\
**Post date:** [September 7, 2026, 1:34pm UTC](https://discourse.odriverobotics.com/t/command-id-0x08-on-can-bus/14529/1 "2026-09-07T13:34:37Z")

</div>

Hello, I have been using ODrive S1 for controlling 150KV motor using ODrive USB TO CAN adapter and a AI built CAN viewer tool on my laptop. It worked well. However I have now connected the system with a Teensy 4.1 and a compatible transceiver. When I read CAN Bus, I see 0x08 from same node ID 0 as ODrive (Teensy node id is set to 1) which I have never seen before and is not in the dbc too. I am attaching a CAN log and sketch of my setup. Has anyone ever faced this? Any suggestions are appreciated.  
Thanks!

 ![image](https://discourse.odriverobotics.com/uploads/default/original/2X/1/13bedb664208fa420bbcad5bf7f879bf862e492f.png)  
 ![image](https://discourse.odriverobotics.com/uploads/default/original/2X/3/350e89b33eb31a0bc6716f328d5acc032056994e.png)

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<div class="post-metadata">

**Author:** ![solomondg](https://discourse.odriverobotics.com/letter_avatar_proxy/v4/letter/s/bcef8e/32.png) [@solomondg](https://discourse.odriverobotics.com/u/solomondg)\
**Post date:** [September 7, 2026, 5:06pm UTC](https://discourse.odriverobotics.com/t/command-id-0x08-on-can-bus/14529/2 "2026-09-07T17:06:29Z")

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Those aren’t from the ODrive – they’re CAN error frames from the USB-CAN adapter. It reports bus errors as ID 0x20000008 (error flag + protocol error); mask off the flag and you’re left with node 0, command 0x08. Byte 2 is the error type (0x04 stuff error, 0x02 form error) and the last byte is the adapter’s receive error counter, pegged at 255. So the bus has been erroring continuously since the Teensy joined – the ODrive itself never sends 0x08.

If the viewer’s on python-can, those messages will have is\_error\_frame == True. Pulling the Teensy’s transceiver off CANH/CANL should make them disappear entirely.

The Teensy’s own frames decode fine, so I’d look at the physical layer rather than the sketch. A few questions:

- Which transceiver, and what’s it powered from? The Teensy is 3.3V-only – a 5V transceiver like a TJA1050 can be marginal on a 3.3V TXD, and its 5V RXD isn’t safe for the Teensy either.
- How many 120R terminators are on the bus? Should be exactly two, at the ends. A lot of SN65HVD230 breakouts have one soldered on, and the adapter has its own switch.
- What bitrate and clock setting are you giving FlexCAN\_T4?

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<div class="post-metadata">

**Author:** ![akshat\_joshi](https://discourse.odriverobotics.com/user_avatar/discourse.odriverobotics.com/akshat_joshi/32/7805_2.png) [@akshat\_joshi](https://discourse.odriverobotics.com/u/akshat_joshi)\
**Post date:** [September 10, 2026, 2:05am UTC](https://discourse.odriverobotics.com/t/command-id-0x08-on-can-bus/14529/3 "2026-09-10T02:05:19Z")

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1. I am using SN65HVD230 CAN Bus Transceiver for Teensy 4.1 and its getting powered from Teensy itself (3V pin)
2. When I measure total CAN bus resistance it comes around 60 ohms, so I assumed resistance should be fine.
3. Yes I think it was baudrate. It was set to 1000000 while my CAN was on 500K.  
It doesnt have any question marks now. Thanks

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<div class="post-metadata">

**Author:** ![solomondg](https://discourse.odriverobotics.com/letter_avatar_proxy/v4/letter/s/bcef8e/32.png) [@solomondg](https://discourse.odriverobotics.com/u/solomondg)\
**Post date:** [September 10, 2026, 4:17am UTC](https://discourse.odriverobotics.com/t/command-id-0x08-on-can-bus/14529/4 "2026-09-10T04:17:17Z")

</div>

Could you send some pictures of the wiring? Or is everything working now?

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<div class="post-metadata">

**Author:** ![akshat\_joshi](https://discourse.odriverobotics.com/user_avatar/discourse.odriverobotics.com/akshat_joshi/32/7805_2.png) [@akshat\_joshi](https://discourse.odriverobotics.com/u/akshat_joshi)\
**Post date:** [September 12, 2026, 12:40am UTC](https://discourse.odriverobotics.com/t/command-id-0x08-on-can-bus/14529/5 "2026-09-12T00:40:44Z")

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Yes the CAN works now, the issue is now that Teensy is not able to read the CAN message, so I think it’s more of teensy to transceiver issue than an ODRIVE.  
Here is my wiring although.

 ![1000082748](https://discourse.odriverobotics.com/uploads/default/original/2X/1/1ff909c0627b7423914a7fc9558741382fe64194.jpeg)

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<div class="post-metadata">

**Author:** ![solomondg](https://discourse.odriverobotics.com/letter_avatar_proxy/v4/letter/s/bcef8e/32.png) [@solomondg](https://discourse.odriverobotics.com/u/solomondg)\
**Post date:** [September 12, 2026, 3:36pm UTC](https://discourse.odriverobotics.com/t/command-id-0x08-on-can-bus/14529/6 "2026-09-12T15:36:31Z")

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Would you mind sharing your Teensy code?

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<div class="post-metadata">

**Author:** ![akshat\_joshi](https://discourse.odriverobotics.com/user_avatar/discourse.odriverobotics.com/akshat_joshi/32/7805_2.png) [@akshat\_joshi](https://discourse.odriverobotics.com/u/akshat_joshi)\
**Post date:** [September 12, 2026, 4:05pm UTC](https://discourse.odriverobotics.com/t/command-id-0x08-on-can-bus/14529/7 "2026-09-12T16:05:08Z")

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sure. The code below looks to set to toggle built in LED when it receives message (it also has code for external RGB LEDs, but not used). The code is used to blink the LED but since the rate is 10ms for the message looking for message from my CAN tool addressed to teensy on node ID 01, it should be fast enough to look like always ON LED once messages start

/\*

- Teensy 4.1 — CAN message watcher + status reporter
- 
- What it does:
- 
  - Listens on CAN1 for frames addressed to this Teensy (or broadcast).

- 
  - Each received message:

- 

```
  * blinks the built-in LED (pin 13) once

```

- 

```
  * lights an external RGB LED in a color that depends on the command ID

```

- 
  - Every STATUS\_PERIOD\_MS it sends a return CAN frame containing:

- 

```
  byte 0 = 1 if a message was received within IDLE_TIMEOUT_MS

```

- 

```
  byte 0 = 0 if no message is being received

```

- 
- Return frame (what the ODrive CAN Viewer will show):
- CAN ID = (TEENSY\_NODE\_ID \<\< 5) | STATUS\_CMD\_ID
- 

```
      = (1 << 5) | 0x1E = 0x3E (node 1, cmd 0x1E)

```

- DLC = 1
- Data = 01 (reading) or 00 (idle)
- 
- Wiring (same as before):
- 
  - Teensy 4.1 CAN1: TX = pin 22, RX = pin 23

- 
  - External CAN transceiver (SN65HVD230 / TJA1050) on pins 22/23, plus

- 

```
120 ohm termination.

```

- 
  - Built-in LED: pin 13 (single-color orange — used for the blink).

- 
- RGB LED (for the “different colors” — the Teensy’s built-in LED is only
- one color, so this needs an external RGB LED):
- 
  - Common CATHODE RGB:

- 

```
  R -> pin 2, G -> pin 3, B -> pin 4 (each through ~220 ohm)

```

- 

```
  common cathode -> GND

```

- 

```
  set COMMON_ANODE = false

```

- 
  - Common ANODE RGB:

- 

```
  R -> pin 2, G -> pin 3, B -> pin 4 (each through ~220 ohm)

```

- 

```
  common anode -> 3.3V

```

- 

```
  set COMMON_ANODE = true

```

- Set RGB\_ENABLE = 0 if you only want the built-in blink and no RGB LED.
- 
- Library: FlexCAN\_T4 (Tools → Manage Libraries → “FlexCAN\_T4”)
- Board: Tools → Board → Teensy → Teensy 4.1  
\*/

#include \<FlexCAN\_T4.h\>

// ---------------------------------------------------------------------------  
// Configuration  
// ---------------------------------------------------------------------------  
#define TEENSY\_NODE\_ID 1 // CAN node ID this Teensy listens on / replies as  
#define STATUS\_CMD\_ID 0x1E // custom command ID for the 1/0 status frame

#define CAN\_BAUDRATE 500000 // must match the ODrive CAN Viewer bitrate (500 kbps)

#define LED\_PIN 13 // built-in LED

#define RGB\_ENABLE 1 // set to 0 if no external RGB LED  
#define RED\_PIN 2  
#define GREEN\_PIN 3  
#define BLUE\_PIN 4  
#define COMMON\_ANODE false // true = common-anode RGB (LOW turns a channel on)

#define IDLE\_TIMEOUT\_MS 500 // no message for this long =\> report 0  
#define STATUS\_PERIOD\_MS 100 // how often to send the status frame

#define SERIAL\_DEBUG 1 // print status changes to Serial (115200 baud)

FlexCAN\_T4\<CAN1, RX\_SIZE\_256, TX\_SIZE\_16\> canBus;

// Shared with the CAN receive callback (runs in interrupt context).  
volatile bool gotMessage = false;  
volatile uint32\_t lastRxTime = 0;  
volatile uint8\_t lastCmdId = 0;

// ---------------------------------------------------------------------------  
// RGB helper  
// ---------------------------------------------------------------------------  
#if RGB\_ENABLE  
void setRgb(uint8\_t r, uint8\_t g, uint8\_t b) {  
if (COMMON\_ANODE) {  
analogWrite(RED\_PIN, 255 - r);  
analogWrite(GREEN\_PIN, 255 - g);  
analogWrite(BLUE\_PIN, 255 - b);  
} else {  
analogWrite(RED\_PIN, r);  
analogWrite(GREEN\_PIN, g);  
analogWrite(BLUE\_PIN, b);  
}  
}

void setColorForCmd(uint8\_t cmdId) {  
switch (cmdId) {  
case 0x07: setRgb(255, 0, 0); break; // Set\_Axis\_State → red  
case 0x0B: setRgb( 0, 255, 0); break; // Set\_Controller\_Mode → green  
case 0x0D: setRgb( 0, 0, 255); break; // Set\_Input\_Vel → blue  
case 0x0C: setRgb(255, 255, 0); break; // Set\_Input\_Pos → yellow  
case 0x02: setRgb(255, 255, 255); break; // Estop → white  
case 0x00: setRgb( 0, 255, 255); break; // Get\_Version → cyan  
case 0x01: setRgb(255, 0, 255); break; // Heartbeat → magenta  
default: setRgb(255, 255, 255); break; // anything else → white  
}  
}  
#endif

// ---------------------------------------------------------------------------  
// CAN helpers  
// ---------------------------------------------------------------------------  
void sendStatus(uint8\_t status) {  
CAN\_message\_t msg;  
msg.id = (TEENSY\_NODE\_ID \<\< 5) | STATUS\_CMD\_ID;  
msg.len = 1;  
msg.buf[0] = status;  
canBus.write(msg);  
}

void onCanReceive(const CAN\_message\_t &msg) {  
uint32\_t nodeId = (msg.id \>\> 5) & 0x3F;  
uint32\_t cmdId = msg.id & 0x1F;

// Ignore frames addressed to other nodes (e.g. the ODrive’s own traffic).  
// 0x3F is the broadcast node ID.  
if (nodeId != TEENSY\_NODE\_ID && nodeId != 0x3F) {  
return;  
}

lastCmdId = (uint8\_t)cmdId;  
lastRxTime = millis();  
gotMessage = true;  
}

// ---------------------------------------------------------------------------  
// Setup / loop  
// ---------------------------------------------------------------------------  
void setup() {  
Serial.begin(115200);  
delay(100);

pinMode(LED\_PIN, OUTPUT);  
digitalWrite(LED\_PIN, LOW);

#if RGB\_ENABLE  
pinMode(RED\_PIN, OUTPUT);  
pinMode(GREEN\_PIN, OUTPUT);  
pinMode(BLUE\_PIN, OUTPUT);  
setRgb(0, 0, 0);  
#endif

canBus.begin();  
canBus.setBaudRate(CAN\_BAUDRATE);  
canBus.setMaxMB(16);  
canBus.enableFIFO();  
canBus.enableFIFOInterrupt();  
canBus.onReceive(onCanReceive);

Serial.println(“Teensy CAN watcher ready.”);  
}

void loop() {  
static bool ledState = false;

// — Blink built-in LED once per message, and refresh the RGB color —  
if (gotMessage) {  
gotMessage = false;  
ledState = !ledState;  
digitalWrite(LED\_PIN, ledState ? HIGH : LOW);  
#if RGB\_ENABLE  
setColorForCmd(lastCmdId);  
#endif  
}

// — Idle detection —  
bool active = (millis() - lastRxTime) \< IDLE\_TIMEOUT\_MS;

#if RGB\_ENABLE  
static bool lastActive = false;  
if (active != lastActive) {  
lastActive = active;  
if (!active) {  
setRgb(0, 0, 0); // no traffic → RGB off  
}  
}  
#endif

// — Send the 1/0 status frame periodically —  
static uint32\_t lastStatusSent = 0;  
if (millis() - lastStatusSent \>= STATUS\_PERIOD\_MS) {  
lastStatusSent = millis();  
sendStatus(active ? 1 : 0);

#if SERIAL\_DEBUG  
static uint8\_t lastReported = 0xFF;  
uint8\_t now = active ? 1 : 0;  
if (now != lastReported) {  
lastReported = now;  
Serial.print("Status: ");  
Serial.println(now);  
}  
#endif  
}  
}

---

<div class="post-metadata">

**Author:** ![solomondg](https://discourse.odriverobotics.com/letter_avatar_proxy/v4/letter/s/bcef8e/32.png) [@solomondg](https://discourse.odriverobotics.com/u/solomondg)\
**Post date:** [September 14, 2026, 6:05pm UTC](https://discourse.odriverobotics.com/t/command-id-0x08-on-can-bus/14529/8 "2026-09-14T18:05:24Z")

</div>

The code looks fine to me – the FlexCAN\_T4 setup matches the library examples, and the node/command ID math is right.

In your wiring photo the Teensy socket on the DIN breakout looks empty – was it just pulled for the picture?

A few questions:

- Do the Teensy’s status frames (ID 0x3E) show up in your viewer? If they do, the Teensy’s TX, RX and bitrate are all working (it can’t get a frame onto the bus without reading it back), so the issue would be what’s being sent to it.
- What exactly is your tool sending to node 1? A viewer log of those frames would help.

Quick test: comment out the node ID check in onCanReceive and print msg.id to Serial. The ODrive’s heartbeat (ID 0x001) should show up 10x/second either way.

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<div class="post-metadata">

**Author:** ![akshat\_joshi](https://discourse.odriverobotics.com/user_avatar/discourse.odriverobotics.com/akshat_joshi/32/7805_2.png) [@akshat\_joshi](https://discourse.odriverobotics.com/u/akshat_joshi)\
**Post date:** [September 17, 2026, 12:38am UTC](https://discourse.odriverobotics.com/t/command-id-0x08-on-can-bus/14529/9 "2026-09-17T00:38:48Z")

</div>

Yes sorry, teensy was just removed from DIN Breakout before the photo.

1. No I dont see Teensy frames in my viewer, so I suspect either teensy is not receiving anyting to respond through transceiver.
2. The tool is sending similar command of set input velocity to Teensy as a target (Node 1) instead of ODrive. It is just to test communication from CAN viewer to Teensy. I am adding the logs here. However there is still some time sync issue between ODrive clock and Teensy clock probably that you might see in logs, I dont think that should be a cause though.[CAN Log](https://drive.google.com/file/d/1MIyorsSIkYUvLKuzcNJHzh8bHcebG36H/view?usp=sharing)

---

<div class="post-metadata">

**Author:** ![solomondg](https://discourse.odriverobotics.com/letter_avatar_proxy/v4/letter/s/bcef8e/32.png) [@solomondg](https://discourse.odriverobotics.com/u/solomondg)\
**Post date:** [September 17, 2026, 3:01am UTC](https://discourse.odriverobotics.com/t/command-id-0x08-on-can-bus/14529/10 "2026-09-17T03:01:59Z")

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Gotcha. Agreed this might just be a transciever issue – worth checking the D/R lines between the Teensy and the transciever with a logic analyzer or oscilloscope.