MCP2515 CAN Bit Timing Calculator

Calculate practical MCP2515 CAN timing values with oscillator frequency, target bitrate, sample point, SJW, and optional triple sampling.

MCP2515 timing and CNF register calculator

Inputs

Oscillator frequency (MHz) Target bitrate (kbps)

Target sample point (%) SJW

Enable triple sampling (SAM bit) Candidate rows

Best match

Actual bitrate-

Bitrate error-

Actual sample point-

Sample point error-

Time quantum (TQ)-

Total TQ-

BRP-

PropSeg-

PhaseSeg1-

PhaseSeg2-

SJW-

CNF1-

CNF2-

CNF3-

Enter oscillator and bitrate values to calculate MCP2515 timing.

Top candidate configurations

Rank	Bitrate	Bitrate error	Sample point	BRP	PropSeg	PhaseSeg1	PhaseSeg2	CNF1/CNF2/CNF3
No candidate yet.

Register snippet

What is MCP2515 CAN bit timing?

MCP2515 CAN timing is defined by time quantum and segment values that must match oscillator frequency and target CAN bitrate. A small mismatch can prevent bus communication.

CNF1, CNF2 and CNF3 registers

CNF1 holds BRP and SJW. CNF2 holds BTLMODE, SAM, PHSEG1, and PRSEG. CNF3 holds PHSEG2. This tool provides practical values based on datasheet-style bit timing ranges.

Bitrate, time quantum and sample point

The calculator searches valid BRP, PropSeg, PhaseSeg1, and PhaseSeg2 combinations, then ranks candidates by bitrate error and sample-point closeness.

MCP2515 reference examples

Oscillator	Bitrate	Typical use	Notes
8 MHz	125 kbps	Low-speed CAN modules	Common low-cost MCP2515 board setting
8 MHz	500 kbps	Automotive experiments	Check oscillator marking carefully
16 MHz	250 kbps	Industrial CAN	Common stable setting
16 MHz	500 kbps	OBD/CAN projects	Very common MCP2515 setting
16 MHz	1 Mbps	Short bus	Requires careful wiring and termination

Common MCP2515 oscillator and bitrate examples

Typical module combinations include 8 MHz or 16 MHz oscillator with 125 kbps to 500 kbps bitrates. Always verify the crystal marking on your board.

FAQ

What are CNF1, CNF2 and CNF3 on MCP2515?

They are MCP2515 timing configuration registers used to set BRP, segment lengths, SJW, and optional triple sampling.

Why does the oscillator frequency matter for MCP2515?

Bit timing is derived directly from oscillator frequency. If firmware assumes 16 MHz but hardware is 8 MHz, bitrate will be wrong.

What sample point should I use for CAN?

Many practical CAN networks use around 75 to 87.5 percent sample point. Choose values based on transceiver, bus length, and controller limits.

Why does my MCP2515 module not communicate at the selected bitrate?

Common causes are wrong oscillator assumption, poor wiring, missing termination, or sample-point mismatch against other nodes.

Is an 8 MHz MCP2515 module different from a 16 MHz module?

Yes. The same CNF register values produce different bitrates across oscillator frequencies, so firmware settings must match the module crystal.