mc68hc908qz16 Freescale Semiconductor, Inc, mc68hc908qz16 Datasheet - Page 132

• Manufacturer Part Number: mc68hc908qz16
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

MSCAN08 Controller (MSCAN08)
After wakeup, the MSCAN08 waits for 11 consecutive recessive bits to synchronize to the bus. As a
consequence, if the MSCAN08 is woken-up by a CAN frame, this frame is not received. The receive
message buffers (RxFG and RxBG) contain messages if they were received before sleep mode was
entered. All pending actions are executed upon wakeup: copying of RxBG into RxFG, message aborts
and message transmissions. If the MSCAN08 is still in bus-off state after sleep mode was left, it continues
counting the 128*11 consecutive recessive bits.
12.8.2 MSCAN08 Soft Reset Mode
In soft reset mode, the MSCAN08 is stopped. Registers can still be accessed. This mode is used to
initialize the module configuration, bit timing and the CAN message filter. See
Control Register 0
When setting the SFTRES bit, the MSCAN08 immediately stops all ongoing transmissions and
receptions, potentially causing CAN protocol violations.
12.8.3 MSCAN08 Power-Down Mode
The MSCAN08 is in power-down mode when the CPU is in stop mode.
When entering the power-down mode, the MSCAN08 immediately stops all ongoing transmissions and
receptions, potentially causing CAN protocol violations.
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The user is responsible to take care that the MSCAN08 is not active when
soft reset mode is entered. The recommended procedure is to bring the
MSCAN08 into sleep mode before the SFTRES bit is set.
The user is responsible to take care that the MSCAN08 is not active when
power-down mode is entered. The recommended procedure is to bring the
MSCAN08 into sleep mode before the STOP instruction is executed.
for a complete description of the soft reset mode.
MSCAN08 SLEEPING
or MSCAN08
MCU
SLPRQ = 1
Figure 12-7. Sleep Request/Acknowledge Cycle
SLPAK = 1
MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 4
MSCAN08 RUNNING
SLPRQ = 0
SLPAK = 0
MSCAN08
NOTE
NOTE
SLEEP REQUEST
SLPRQ = 1
SLPAK = 0
MCU
12.13.1 MSCAN08 Module
Freescale Semiconductor