CAN (Controller Area Network) Controlled Analog/Digital Input/Output Module
- Control analog outputs by CAN messages
- Control digital outputs by CAN message
- Monitor analog inputs via CAN message
- Monitor digital inputs via CAN message
⚠️ Check supply and I/O voltages carefully and build up your circuit accordingly!
⚠️ Over voltage/over current protection for analog and digital inputs/outputs must be implemented as required!
⚠️ Implement voltage dividers and filter capacitors for analog inputs as required.
| Program | MCU | Board | Devel.-Env. | Supply Voltage Board/MCU |
Analog Inputs | Analog Outputs | Digital Inputs | Digital Outputs |
|---|---|---|---|---|---|---|---|---|
| ESP32_MCP2515_CAN_IO | ESP32 | generic (e.g. Joy-It SBC-NodeMCU-ESP32) |
Arduino | 5V(1) / 3.3V | 2(2) (0...3.3V) | 2(3) (external; 0...5V) | 6(2) | 2(2) |
| ESP32_IntegratedSJA1000 _CAN_IO |
ESP32 | generic (e.g. Joy-It SBC-NodeMCU-ESP32) |
Arduino | 5V(1) / 3.3V | 2(2) (0...3.3V) | 2(3) (external; 0...5V) | 6(2) | 2(2) |
| ATSAME51_CAN_IO | ATSAME51 | Adafruit Feather M4 CAN Express | Arduino | 5V(1) / 3.3V(1) | 4 (0...3.3V) | 2 (internal; 0..3.3V) / 2(3) (external; 0..5V) |
6 | 2 |
| AT90CAN128_CAN_IO | AT90CAN128 | Crumb128-CAN | AVR-GCC | 5V(1) / 5V | 4(4) (0...5V) | 2(3) (external; 0...5V) | 8(5) | 8(5) |
(1) Supply voltage level and quality have direct impact on the DACs' output signals. For instance, you won't get a 5V analog output from a USB power supply (due to the typical schottky diode between VDDUSB and VDD5V).
(2) ESP32 allows great flexibility of utilizing I/O pins - the numbers provided here are only for the default configuration. The actual number of I/O pins varies with different boards.
(3) More DAC channels possible with MCP4725 devices with suitable I2C addresses
(4) More ADC channels are available if required
(5) More I/O ports are available if required
| Program | MCU | Board | CAN Controller | CAN Transceiver | CAN Bus Termination |
|---|---|---|---|---|---|
| ESP32_MCP2515_CAN_IO | ESP32 | generic (e.g. Joy-It SBC-NodeMCU-ESP32) |
external (MCP2515)(1) | external(1) | external(1)(2) |
| ESP32_IntegratedSJA1000 _CAN_IO |
ESP32 | generic (e.g. Joy-It SBC-NodeMCU-ESP32) |
internal | external | external |
| ATSAME51_CAN_IO | ATSAME51 | Adafruit Feather M4 CAN Express | internal | Adafruit Feather M4 CAN Express: on board | Adafruit Feather M4 CAN Express: 120 Ohm on board; trace "Trm" needs to be cut if not needed |
| AT90CAN128_CAN_IO | AT90CAN128 | Crumb128-CAN | internal | Crumb128-CAN: on board | external |
(1) Tested with AZDelivery MCP2515 CAN Bus Module
(2) AZDelivery MCP2515 CAN Bus Module: enable 120 Ohm termination with jumper J1
Currently no effort is made to synchronize the various inputs and outputs -
- CAN_ID_DOUT message reception -> update digital outputs
- CAN_ID_AOUT0/1 message reception -> start DAC for analog output 0/1, respectively
- read analog inputs (sequentially) -> transmit CAN_ID_AIN message
- read digital inputs -> transmit CAN_ID_DIN message
Please take the conversion time (and transmission time, if applicable) of your DACs/ADCs into account.
-
Configure fuses on a fresh MCU - see AVR Fuse Calculator
- Switch off "Divide clock by 8 internally":
- Switch to external clock oscillator >= 8 MHz (here: with a very conservative startup time...)
avrdude -c <programmer> -P <port> -p at90can128 -U lfuse:w:0xFF:m -
The SW is configured for a 16 MHz crystal
-
Set J6 "USBpowered" if desired
-
Set J8 "HighSpeed CAN" if you don't have other requirements