MC68HC08AZ32A Datasheet, PDF (344/456 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
MSCAN08 Controller (MSCAN08)
f_Tq =
f_MSCANCLK
Presc value
A bit time is subdivided into three segments⁽¹⁾(see Figure 20-8).
• SYNC_SEG: This segment has a fixed length of one time
quantum. Signal edges are expected to happen within this section.
• Time segment 1: This segment includes the PROP_SEG and the
PHASE_SEG1 of the CAN standard. It can be programmed by
setting the parameter TSEG1 to consist of 4 to 16 time quanta.
• Time segment 2: This segment represents PHASE_SEG2 of the
CAN standard. It can be programmed by setting the TSEG2
parameter to be 2 to 8 time quanta long.
f_Tq
Bit rate=
No. of time quanta
The synchronization jump width (SJW) can be programmed in a range
of 1 to 4 time quanta by setting the SJW parameter.
The above parameters can be set by programming the bus timing
registers, CBTR0–CBTR1, see MSCAN08 Bus Timing Register 0 on
page 358 and MSCAN08 Bus Timing Register 1 on page 359).
NOTE: It is the user’s responsibility to make sure that the bit timing settings are
in compliance with the CAN standard,
Table 20-8 gives an overview on the CAN conforming segment settings
and the related parameter values.
Technical Data
344
1. For further explanation of the underlying concepts please refer to ISO/DIS 11 519-1, Section
10.3.
MC68HC08AZ32A — Rev 1.0
MSCAN08 Controller (MSCAN08)
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