Freescale Semiconductor, Inc.
Interrupts
• SCI Receiver Overrun Interrupt — The overrun bit (OR)
indicates that a received byte is lost because software has not
read the previously received byte. OR becomes set when a byte
shifts into the receive shift register before software reads the word
already in the SCI data register. OR generates an interrupt
request if the receive interrupt enable bit (RIE) is set also.
• SCI Receiver Input Idle Interrupt — The receiver input idle bit
(IDLE) indicates that the SCI receiver input is not receiving data.
IDLE becomes set when 10 or 11 consecutive logic 1s appear on
the receiver input. IDLE generates an interrupt request if the idle
line interrupt enable bit (ILIE) is set also.
4.3.6 SPI Interrupts
The serial peripheral interrupt (SPI) can generate these interrupts:
• SPI transmission complete interrupt
• SPI mode fault interrupt
Setting the I bit in the CCR disables all SPI interrupts.
• SPI Transmission Complete Interrupt — The SPI flag bit (SPIF)
in the SPI status register indicates the completion of an SPI
transmission. SPIF becomes set when a byte shifts into or out of
the SPI data register. SPIF generates an interrupt request if the
SPIE bit is set also.
• SPI Mode Fault Interrupt — The mode fault bit (MODF) in the SPI
status register indicates an SPI mode error. MODF becomes set
when a logic 0 occurs on the PD5/SS pin while the master bit
(MSTR) in the SPI control register is set. MODF generates an
interrupt request if the SPIE bit is set also.
Technical Data
56
MC68HC705C8A — Rev. 3
Interrupts
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