Microchip Technology dsPIC33 series User Manual

 2018 Microchip Technology Inc. DS70005340A-page 57
CAN FD Protocol Module
5.0 CONFIGURATION
5.1 Clock Configuration
The sample point of all nodes in a CAN FD network should be at the same position. Hence, it is
recommended to use the same clock frequency and bit time settings for all nodes. Therefore, a
SYSCLK of 80 MHz, 40 MHz, 20 MHz or 10 MHz is recommended
The CLKSEL bit allows the selection of the clock source to the CAN FD module.
• If CLKSEL = 1, then the auxiliary clock will be selected as a clock source
• If CLKSEL = 0, then the clock from the CAN clock generator will be selected
The following register is used to configure the CAN clock generator.
Register 5-1: CANCLKCON: CAN Clock Control Register
(1)
R/W-0 U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0
CANCLKEN
— — — CANCLKSEL<3:0>
(1)
bit 15 bit 8
U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— CANCLKDIV<6:0>
(2,3)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 15 CANCLKEN: CAN Clock Generator Enable bit
1 = CAN clock generation circuitry is enabled
0 = CAN clock generation circuitry is disabled
bit 14-12 Unimplemented: Read as ‘0’
bit 11-8 CANCLKSEL<3:0>: Can Clock Source Select bits
(1)
1011-1111 = Reserved (no clock selected)
1010 = AF VCO /4 clock
1001 = AF
VCO /3 clock
1000 = AF VCO /2 clock
0111 = AF
PLLVCO clock
0110 = Auxiliary clock
0101 = VCO/4 clock
0100 = VCO/3 clock
0011 = VCO/2 clock
0010 = PLLDIV clock
0001 = VCO clock
0000 = 0 (No clock selected)
bit 7 Unimplemented: Read as ‘0’
bit 6-0 CANCLKDIV<6:0>: CAN Clock Divider Select bits
(2,3)
1111111 = Divide by 128
•••
0000010 = Divide by 3
0000001 = Divide by 2
0000000 = Divide by 1
Note 1: The user must ensure the input clock source is 640 MHz or less. Operation with input reference frequency
above 640 MHz will result in unpredictable behavior.
2: The CANCLKDIVx divider value must not be changed during CAN module operation.
3: The user must ensure the maximum clock output frequency of the divider is 80 MHz or less.

Microchip Technology dsPIC33 series Specifications

General

Brand	Microchip Technology
Model	dsPIC33 series
Category	Motherboard
Language	English