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[ESP32_CAN] Add documentation for advanced bit rate settings on ESP32_CAN component #5503

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[ESP32_CAN] Add documentation for advanced bit rate settings on ESP32_CAN component #5503

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840146c
Add advanced bit rate documentation
ziceva Oct 20, 2025
e0a5001
Fix formula
ziceva Oct 20, 2025
dc66a3a
Fix formatting; Fix formula
ziceva Oct 20, 2025
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18 changes: 17 additions & 1 deletion content/components/canbus/esp32_can.md
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,10 @@ canbus:
rx_pin: GPIOXX
can_id: 4
bit_rate: 50kbps
advanced_bit_rate:
prescaler: 80
tseg_1: 15
tseg_2: 4
on_frame:
...
```
Expand All @@ -32,7 +36,7 @@ canbus:
- **tx_queue_len** (*Optional*, int): Length of TX queue, 0 to disable.
- **tx_enqueue_timeout** (*Optional*, [Time](#config-time)): Maximum time to wait when the TX queue is full before
dropping the message (by default, this is set to the time it takes to send 10 CAN messages at the given bit rate).

- **advanced_bit_rate** (*Optional*): When present, overrides the bit_rate setting and allows fine tunning of the bit rate.
- All other options from [Canbus](#config-canbus).

{{< anchor "esp32-can-bit-rate" >}}
Expand Down Expand Up @@ -62,6 +66,18 @@ The following table lists the bit rates supported by the component for ESP32 var
| 800KBPS | x | x | x | x | x | x |
| 1000KBPS | x | x | x | x | x | x |

## Advanced bit rate option

- **prescaler** (**Required**, int): Prescaler to compute the time quanta.
- **tseg_1** (**Required**, int): An integer between 1 and 16.
- **tseg_2** (**Required**, int): An integer between 1 and 8.

The bit rate is computed as:

$$bit\\_rate = {{80 MHz} \over prescaler * (1 + tseg\\_1 + tseg\\_2)}$$

**tseg_1** and **tseg_2** control the moment the signal is being sampled.

## Wiring options

5V CAN transceivers are cheap and generate compliant levels. If you power your
Expand Down