27 Feb 2018
Pluggable CAN Connectivity
The Seal USB/CAN adapter runs the same firmware that powers the CAN functionality on Theobroma Systems compute modules in the Q7 format. The USB-stick form-factor enables adding CAN connectivity to any computer running Linux, or adding extra CAN interfaces to a Theobroma Systems Q7 module.
The Seal v2.3 firmware (available for download on the product page) adds improved robustness and overload condition handling, achieving 0.0% CAN frame loss at any bit rate up to 1 Mbit.
The Linux driver supports an unlimited number of Seal devices on a single host. Each Seal device is identified through a globally-unique 96-bit serial number that is exposed through the Linux-standard ID_SERIAL_SHORT property.
The Seal USB/CAN Adapter implements the UCAN wire protocol on USB that has been designed to be as generic and hardware-independent as possible in the hope of being useful for implementation on other devices. An open-source driver including protocol specification has been submitted for inclusion in mainline Linux, and we will try to address any change requests to get it merged.
Until UCAN drivers are readily available in distribution kernels, Theobroma Systems will provide the UCAN driver as a loadable kernel module for Linux. Some experience in compiling software is required. The code is available from https://git.theobroma-systems.com/ucan-linux-module.git/ .
- USB 2.0 Full-Speed Interface
- Standard SocketCAN Interface (“can0”)
- Flexible CAN bit rate up to 1 MBit/s
- Flexible sampling point (defaults to CiA recommendation)
- Configured through the standard “ip” tool
- Firmware upgradeable via USB using DFU
- High-speed CAN transceiver with integrated ±16kV ESD protection
- Power-off fail-safe (transceiver switches to high impedance on Vcc loss)
- On-board 120 Ω termination resistor