Datasheet

Section 15 Controller Area Network for Tiny (TinyCAN)
Rev. 4.00 Mar. 15, 2006 Page 326 of 556
REJ09B0026-0400
Time Quantum (TQ) is an integer multiple of the number of system clocks, and is determined by
the baud rate prescaler (BRP) as follows. φ means the system clock frequency.
TQ = (BRP + 1)/φ
The following formula is used to calculate the 1-bit time and bit rate.
1-bit time = TQ × {1 + (1 + TSG1) + (1 + TSG2)}
Bit rate = 1/Bit time
= φ/{(BRP + 1) × {1 + (1 + TSG1) + (1 + TSG2)}}
Values that can be set for TSG1 and TSG2 in BCR1 are listed in table 15.3.
Table 15.3 Settable Values for TSG1 and TSG2 in BCR1
TSG2
001 010 011 100 101 110 111
TSG1 0011 No Yes No No No No No
0100 Yes Yes Yes No No No No
0101 Yes Yes Yes Yes No No No
0110 Yes Yes Yes Yes Yes No No
0111 Yes Yes Yes Yes Yes Yes No
1000 Yes Yes Yes Yes Yes Yes Yes
1001 Yes Yes Yes Yes Yes Yes Yes
1010 Yes Yes Yes Yes Yes Yes Yes
1011 Yes Yes Yes Yes Yes Yes Yes
1100 Yes Yes Yes Yes Yes Yes Yes
1101 Yes Yes Yes Yes Yes Yes Yes
1110 Yes Yes Yes Yes Yes Yes Yes
1111 Yes Yes Yes Yes Yes Yes Yes
[Legend] Yes: Setting is possible
No: Setting is prohibited
[Example]
To have a baud rate of 1 Mbps with φ = 16 MHz, BRP = 1, and (1 + TSG1) + (1 + TSG2) = 7. In
this case, the settings are BCR1 = H′23 and BCR0 = H'01.