Rainbow Electronics CAN интерфейс - Manual (Page 48)

BOSCH
ROBERT BOSCH GmbH, Postfach 300240, D-7000 Stuttgart 30
Sep. 1991
Part B - page 46
above), and the reserved bit r0. Frames in the Extended Format include the DATA
LENGTH CODE and two reserved bits r1 and r0. The reserved bits have to be sent
’dominant’, but receivers accept ’dominant’ and ’recessive’ bits in all combinations.
DATA LENGTH CODE ( Standard Format as well as Extended Format )
The number of bytes in the DATA FIELD is indicated by the DATA LENGTH CODE.
This DATA LENGTH CODE is 4 bits wide and is transmitted within the CONTROL
FIELD.
Coding of the number of data bytes by the DATA LENGTH CODE
abbreviations:
d ’dominant’
r ’recessive’
IDE / r1 r0 DLC3 DLC2 DLC1 DLC0
or
CRC
Field
Arbitration
Field Data
Field CONTROL FIELD
Data Length Code reserved
bits
Standard Format and Extended Format
0
1
2
3
4
5
6
7
8
d
d
d
d
d
d
d
d
r
d
d
d
d
r
r
r
r
d
d
d
r
r
d
d
r
r
d
d
r
d
r
d
r
d
r
d
DLC3 DLC2 DLC1 DLC0
Number of Data
Bytes
Data Length Code
Data Frame