STM32 SLCAN

using libopencm3 (real OpenSource - no questionable STMicroelectronics License) to build cheapest CAN Adapter ever:

Why Serial (SLCAN) and not USB ?

it's not possible to use CAN and USB at the same time on STM32F103

Schematic

either use MCP2562 or ISO1050 transceiver - not both !

CAN-Interface

/* CAN1 / CAN GPIO */
#define GPIO_CAN_PB_RX                  GPIO8           /* PB8 */
#define GPIO_CAN_PB_TX                  GPIO9           /* PB9 */

Flashing Serial

using SWD interface with st-flash or serial loader stm32-flash (works only with USART1)

/* USART1 GPIO */
#define GPIO_USART1_TX                  GPIO9           /* PA9 */
#define GPIO_USART1_RX                  GPIO10          /* PA10 */

Usage

Hardware handshaking and LEDs usage is still missing as of today - is made sometime.

connect your favorite/cheap 3V3 USB2Serial board to USART2:

/* USART2 GPIO */
#define GPIO_USART2_CTS                 GPIO0           /* PA0 */
#define GPIO_USART2_RTS                 GPIO1           /* PA1 */
#define GPIO_USART2_TX                  GPIO2           /* PA2 */
#define GPIO_USART2_RX                  GPIO3           /* PA3 */

and do:

sudo modprobe can
sudo modprobe can-raw
sudo modprobe slcan
sudo slcand -s5 -S2000000 /dev/ttyUSB0 can0 # CAN Speed 5 ->250 kBaud, 2,000,000 Baud serial
ifconfig can0 up

Now you can use it as SocketCAN interface - enjoy :-)

Links

Schematic https://github.com/GBert/misc/raw/master/stm32-slcan/pictures/arduino_stm32f103c8t6_schematics.png https://github.com/GBert/misc/raw/master/stm32-slcan/pictures/STM32F103C8T6-DEV-BOARD-SCH.pdf

more information here: https://wiki.kewl.org/dokuwiki/boards:vcc-gnd