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MC9S12P64CFT Datasheet, PDF (301/566 Pages) Freescale Semiconductor, Inc – Microcontrollers | |||
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Freescaleâs Scalable Controller Area Network (S12MSCANV3)
8.4.5.7 Disabled Mode
The MSCAN is in disabled mode out of reset (CANE=0). All module clocks are stopped for power saving,
however the register map can still be accessed as speciï¬ed.
8.4.5.8 Programmable Wake-Up Function
The MSCAN can be programmed to wake up from sleep or power down mode as soon as CAN bus activity
is detected (see control bit WUPE in MSCAN Control Register 0 (CANCTL0). The sensitivity to existing
CAN bus action can be modiï¬ed by applying a low-pass ï¬lter function to the RXCAN input line (see
control bit WUPM in Section 8.3.2.2, âMSCAN Control Register 1 (CANCTL1)â).
This feature can be used to protect the MSCAN from wake-up due to short glitches on the CAN bus lines.
Such glitches can result fromâfor exampleâelectromagnetic interference within noisy environments.
8.4.6 Reset Initialization
The reset state of each individual bit is listed in Section 8.3.2, âRegister Descriptions,â which details all
the registers and their bit-ï¬elds.
8.4.7 Interrupts
This section describes all interrupts originated by the MSCAN. It documents the enable bits and generated
ï¬ags. Each interrupt is listed and described separately.
8.4.7.1 Description of Interrupt Operation
The MSCAN supports four interrupt vectors (see Table 8-39), any of which can be individually masked
(for details see Section 8.3.2.6, âMSCAN Receiver Interrupt Enable Register (CANRIER)â to
Section 8.3.2.8, âMSCAN Transmitter Interrupt Enable Register (CANTIER)â).
NOTE
The dedicated interrupt vector addresses are deï¬ned in the Resets and
Interrupts chapter.
Table 8-39. Interrupt Vectors
Interrupt Source
Wake-Up Interrupt (WUPIF)
Error Interrupts Interrupt (CSCIF, OVRIF)
Receive Interrupt (RXF)
Transmit Interrupts (TXE[2:0])
CCR Mask
Local Enable
I bit
CANRIER (WUPIE)
I bit
CANRIER (CSCIE, OVRIE)
I bit
CANRIER (RXFIE)
I bit
CANTIER (TXEIE[2:0])
8.4.7.2 Transmit Interrupt
At least one of the three transmit buffers is empty (not scheduled) and can be loaded to schedule a message
for transmission. The TXEx ï¬ag of the empty message buffer is set.
S12P-Family Reference Manual, Rev. 1.13
Freescale Semiconductor
301
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