AN2283 Freescale Semiconductor / Motorola, AN2283 Datasheet - Page 2

• Manufacturer Part Number: AN2283
• Description: Scalable Controller Area Network (MSCAN)
• Manufacturer: Freescale Semiconductor / Motorola

AN2283/D
Wakeup Interrupt
Wakeup Interrupt
Initialization
2
NOTE:
Motorola Scalable Controller Area Network (MSCAN) Interrupts
While the MSCAN is in Sleep Mode, it will wakeup when bus activity is
detected. The central processor unit (CPU) requests the MSCAN to go into
Sleep Mode after the bus traffic has been halted, typically signaled by a
system-level sleep command message. Once the network is asleep, a wakeup
interrupt will be needed when message traffic resumes to bring the node out of
Sleep Mode.
For further information, refer to MSCAN Low-Power Applications (Motorola
document order number AN2255/D).
Sleep Mode is used to reduce the power consumption in the system. The CPU
requests the MSCAN to enter Sleep Mode by setting the Sleep Request
(SLPRQ) bit in the MSCAN Module Control Register 0 (CMCR0) register (see
Figure
The MSCAN enters Sleep Mode depending on its current activity:
When the MSCAN is running, the control bit SLPRQ = 0 and the status bit Sleep
Mode Acknowledge (SLPAK) = 0 (these bits are located in the CMCR0
register).
Wakeup
Error
Receive
Transmit
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Interrupt Vector
If transmitting, it will continue transmitting until there are no more
messages to be transmitted and then enter the Sleep Mode.
If receiving, it will wait for the end of the message and then enter the
Sleep Mode.
If neither transmitting nor receiving, it will enter the Sleep Mode
immediately.
1).
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Table 1. Error Interrupt Sources
Wakeup interrupt
Overrun interrupt
Bus-off interrupt
Transmitter error passive interrupt
Receiver error passive interrupt
Transmitter warning interrupt
Receiver warning interrupt
Receive buffer full interrupt
Transmit buffer 0 empty interrupt
Transmit buffer 1 empty interrupt
Transmit buffer 2 empty interrupt
Sources
MOTOROLA