CAN SPI Click 3.3V

How does it work?

CAN SPI Click 3.3V is based on the MCP2515, a standalone CAN controller with an SPI interface from Microchip. It implements CAN V2.0B at 1Mbps, capable of transmitting and receiving standard and extended data and remote frames. It features two receive buffers, six 29-bit acceptance filters, and two 29-bit acceptance masks to filter out unwanted messages, thus reducing the host MCU load. Data byte filtering is done on the two first data bytes. In addition, there are three transmit buffers that prioritize and abort the messages.

According to the CAN 2.0B specification, the MCP2515 supports a Standard, Extended, and Remote Data frame. It also comes with an Error frame, an Overload frame, and an Interframe Space. The last one separates a preceding frame of any type from subsequent data or a remote frame. In message transmissions, we distinguish transmit buffers, transmit priority, initiating transmission, One-shot mode, and aborting transmission. There are five modes of operation: Configuration mode, Normal mode, Sleep mode, Listen-only mode, and Loopback mode. No matter the changed mode, the MCP2515 will complete all pending operations.

To communicate with the host MCU, CAN SPI Click 3.3V uses a standard 4-wire SPI serial interface supporting Mode 0 and Mode 3, with speeds up to 10MHz. The RST pin is available for resetting the CAN controller. The interrupt message will be generated on the INT pin, depending on the status. The CAN protocol engine pins TXCAN and RXCAN of the MCP2515 are routed to the screw terminal of the CAN Bus via the SN65HVD230. This transceiver adds a physical layer to the CAN Bus controller. In addition, it also adds ESD protection, high impedance allowing up to 120 nodes to the Bus, thermal shutdown protection, and is designed for data rates of up to 1Mbps.

There is a node termination jumper under the CAN screw terminal labeled with plus and minus signs for CANH and CANL. If the board is the CAN network’s first and last node, then the J2 jumper should be placed. Otherwise, this jumper should be removed if the board is in the middle.

This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

Specifications

Pinout diagram

This table shows how the pinout on CAN SPI Click 3.3V corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	NC
Reset	RST	2	RST	INT	15	INT	Interrupt
SPI Chip Select	CS	3	CS	RX	14	NC
SPI Clock	SCK	4	SCK	TX	13	NC
SPI Data OUT	SDO	5	MISO	SCL	12	NC
SPI Data IN	SDI	6	MOSI	SDA	11	NC
Power Supply	3.3V	7	3.3V	5V	10	NC
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

CAN SPI Click 3.3V electrical specifications