MC68HC05X4 Datasheet, PDF (90/156 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Motorola CAN
Freescale Semiconductor, Inc.
SYNC_SEG
BIT_TIME
TSEG 1
TSEG 2
SYNC_SEG
Transmit point
1 clock cycle
t_SCL
Sample point
Transmit point
Figure 13. Segments within the bit time
SYNC_SEG System expects transitions to occur on the bus during
this period.
Transmit point A node in transmit mode will transfer a new value to the
MCAN bus at this point.
Sample point A node in receive mode will sample the bus at this point.
If the three samples per bit option is selected then this point marks the
position of the third sample.
Time segment 1 (TSEG1) and time segment 2 (TSEG2) are
programmable as shown in Table 3.
Table 3. Time segment values
TSEG13 TSEG12 TSEG11 TSEG10
0
0
0
1
0
0
1
0
0
0
1
1
.
.
.
.
.
.
.
.
1
1
1
1
Time segment 1
2 t_SCL cycles
3 t_SCL cycles
4 t_SCL cycles
.
.
16 t_SCL cycles
TSEG22 TSEG21 TSEG20
0
0
1
.
.
.
.
.
.
1
1
1
Time segment 2
2 t_SCL cycles
.
.
8 t_SCL cycles
The bit time is determined by the oscillator frequency, the baud rate
prescaler, and the number of bus clock cycles (t_SCL) per bit (as shown
above).
MC68HC05X4
Motorola CAN
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Go to: www.freescale.com
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