MC68HC08AZ60A Datasheet, PDF (364/480 Pages) Motorola, Inc – Microcontrollers

MSCAN08 Controller (MSCAN08)
21.9.5 Programmable Wakeup Function
The MSCAN08 can be programmed to apply a low-pass filter function to
the RxCAN input line while in internal sleep mode (see information on
control bit WUPM in MSCAN08 Module Control Register 1 on page
379). This feature can be used to protect the MSCAN08 from wake-up
due to short glitches on the CAN bus lines. Such glitches can result from
electromagnetic inference within noisy environments.
21.10 Timer Link
The MSCAN08 will generate a timer signal whenever a valid frame has
been received. Because the CAN specification defines a frame to be
valid if no errors occurred before the EOF field has been transmitted
successfully, the timer signal will be generated right after the EOF. A
pulse of one bit time is generated. As the MSCAN08 receiver engine also
receives the frames being sent by itself, a timer signal also will be
generated after a successful transmission.
The previously described timer signal can be routed into the on-chip
Timer Interface Module B (TIMB).This signal is connected to the
Channel 0 input under the control of the timer link enable (TLNKEN) bit
in the CMCR0.
After the TIMB module has been programmed to capture rising edge
events, it can be used under software control to generate 16-bit time
stamps which can be stored with the received message.
21.11 Clock System
Figure 21-7 shows the structure of the MSCAN08 clock generation
circuitry and its interaction with the clock generation module (CGM).
With this flexible clocking scheme the MSCAN08 is able to handle CAN
bus rates ranging from 10 kbps up to 1 Mbps.
Advance Information
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MSCAN08 Controller (MSCAN08)
MC68HC08AZ60A — Rev 0.0
MOTOROLA