mc68hc908gr16 Freescale Semiconductor, Inc, mc68hc908gr16 Datasheet - Page 208

• Manufacturer Part Number: mc68hc908gr16
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Serial Peripheral Interface (SPI) Module
16.9 Resetting the SPI
Any system reset completely resets the SPI. Partial resets occur whenever the SPI enable bit (SPE) is
low. Whenever SPE is low, the following occurs:
These items are reset only by a system reset:
By not resetting the control bits when SPE is low, the user can clear SPE between transmissions without
having to set all control bits again when SPE is set back high for the next transmission.
By not resetting the SPRF, OVRF, and MODF flags, the user can still service these interrupts after the
SPI has been disabled. The user can disable the SPI by writing 0 to the SPE bit. The SPI can also be
disabled by a mode fault occurring in an SPI that was configured as a master with the MODFEN bit set.
16.10 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power-consumption standby modes.
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The SPTE flag is set.
Any transmission currently in progress is aborted.
The shift register is cleared.
The SPI state counter is cleared, making it ready for a new complete transmission.
All the SPI port logic is defaulted back to being general-purpose I/O.
All control bits in the SPCR register
All control bits in the SPSCR register (MODFEN, ERRIE, SPR1, and SPR0)
The status flags SPRF, OVRF, and MODF
ERRIE
MODF
OVRF
Figure 16-12. SPI Interrupt Request Generation
SPRIE
SPTE
MC68HC908GR16 Data Sheet, Rev. 5.0
SPTIE
SPRF
SPE
NOT AVAILABLE
SPI TRANSMITTER
CPU INTERRUPT REQUEST
NOT AVAILABLE
SPI RECEIVER/ERROR
CPU INTERRUPT REQUEST
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