mc9s08dz32 Freescale Semiconductor, Inc, mc9s08dz32 Datasheet - Page 265

• Manufacturer Part Number: mc9s08dz32
• Description: Hcs08 Microcontrollers 8-bit Can Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

If the WUPE bit in CANCLT0 is not asserted, the MSCAN will mask any activity it detects on CAN. The
RXCAN pin is therefore held internally in a recessive state. This locks the MSCAN in sleep mode
(Figure
The MSCAN is able to leave sleep mode (wake up) only when:
After wake-up, the MSCAN waits for 11 consecutive recessive bits to synchronize to the CAN bus. As a
consequence, if the MSCAN 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 will be executed upon wake-up; copying of RxBG into RxFG, message
aborts and message transmissions. If the MSCAN remains in bus-off state after sleep mode was exited, it
continues counting the 128 occurrences of 11 consecutive recessive bits.
Freescale Semiconductor
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•
CAN bus activity occurs and WUPE = 1
or
the CPU clears the SLPRQ bit
12-45). WUPE must be set before entering sleep mode to take effect.
The CPU cannot clear the SLPRQ bit before sleep mode (SLPRQ = 1 and
SLPAK = 1) is active.
Figure 12-45. Simplified State Transitions for Entering/Leaving Sleep Mode
StartUp
CAN Activity &
SLPRQ
CAN Activity &
SLPRQ
CAN Activity
MC9S08DZ60 Series Data Sheet, Rev. 3
CAN Activity
CAN Activity
Message
Active
for Idle
Tx/Rx
Wait
Idle
NOTE
SLPRQ
CAN Activity
Chapter 12 Freescale’s Controller Area Network (S08MSCANV1)
(CAN Activity & WUPE) | SLPRQ
Sleep
(CAN Activity & WUPE) |
CAN Activity
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