ICP DAS USA tM-7565 User Manual page 64

Bit
Bit 7
register
Bit Timing 1 -
Bit Timing 2 -
Bit Timing 3 -
Generally, the register of SJW0, SWJ1 and SMP are always 0. One bit time consists of the time
T , T , T , and T
syns prs phs1
system clock. The formula is shown below:
For example, when the CAN baud rate is 40 kbps, the numbers of TQ would be (20 MHz) / (40
Kbps) = 500. It means that the CAN converter can divided one bit time into 500 parts. The
register PRS, PHS1, and PHS2 indicates the numbers of the time slice for T
The formulas are shown below.
T = (PRS+1) * TQ
prs
T = (PHS1+1)* TQ
phs1
T = (PHS2 +1)* TQ
phs2
Because the T is defined to 1 TQ, therefore one bit time can be presented as below.
syns
T
bit
And the sample point is defined below:
I-7530, I-7530-FT, I-7530A, I-7565, tM-7530, tM-7530A, tM-7565 User Manual Version 1.5
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Bit 6 Bit 5
BRP5 BRP4
SJW1 SJW0
PHS22 PHS21
Figure: General structure of a bit period
, and can be divided into numbers of time slice (TQ) according to the
phs2
Numbers of TQ = (System Clock) / (CAN Baud Rate)
= 1 TQ + (PRS+1) * TQ + (PHS1+1)* TQ +(PHS2 +1)* TQ
Bit 4 Bit 3
BRP3 BRP2
- PRS2
PHS20 PHS12
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Bit 2 Bit 1
BRP1 BRP0
PRS1 PRS0
PHS11 PHS10
, T , and T
prs phs1
Page：
Bit 0
-
-
SMP
.
phs2
64