XC908AS60ACFU Motorola Semiconductor Products, XC908AS60ACFU Datasheet - Page 395

• Manufacturer Part Number: XC908AS60ACFU
• Description: MC68HC908AZ60A, MC68HC908AS60A Hcmos Microcontroller Unit Technical Data
• Manufacturer: Motorola Semiconductor Products

23.9.1 MSCAN08 Sleep Mode
MC68HC908AZ60A — Rev 2.0
MOTOROLA
NOTE:
The CPU can request the MSCAN08 to enter the low-power mode by
asserting the SLPRQ bit in the module configuration register (see
23-6). The time when the MSCAN08 enters Sleep mode depends on its
activity:
The application software must avoid setting up a transmission (by
clearing or more TXE flags) and immediately request Sleep mode (by
setting SLPRQ). It then depends on the exact sequence of operations
whether MSCAN08 starts transmitting or goes into Sleep mode directly.
During Sleep mode, the SLPAK flag is set. The application software
should use SLPAK as a handshake indication for the request (SLPRQ)
to go into Sleep mode. When in Sleep mode, the MSCAN08 stops its
internal clocks. However, clocks to allow register accesses still run. If the
•
•
•
if it is transmitting, it continues to transmit until there is no more
message to be transmitted, and then goes into Sleep mode
if it is receiving, it waits for the end of this message and then goes
into Sleep mode
if it is neither transmitting or receiving, it will immediately go into
Sleep mode
Table 23-2. MSCAN08 vs CPU operating modes
MSCAN Controller (MSCAN08)
1. ‘X’ means don’t care.
Power Down
Soft Reset
MSCAN
Normal
Mode
Sleep
SLPAK = X
SFTRES = X
STOP
CPU Mode
(1)
WAIT or RUN
SFTRES = 0
SFTRES = 1
SFTRES = 0
MSCAN Controller (MSCAN08)
SLPAK = 1
SLPAK = 0
SLPAK = 0
Low Power Modes
Technical Data
Figure
395