MC68HC908GT16_07 FREESCALE [Freescale Semiconductor, Inc], MC68HC908GT16_07 Datasheet - Page 215

• Manufacturer Part Number: MC68HC908GT16_07
• Description: Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

ERRIE — Error Interrupt Enable Bit
OVRF — Overflow Bit
MODF — Mode Fault Bit
SPTE — SPI Transmitter Empty Bit
MODFEN — Mode Fault Enable Bit
Freescale Semiconductor
This read/write bit enables the MODF and OVRF bits to generate CPU interrupt requests. Reset clears
the ERRIE bit.
This clearable, read-only flag is set if software does not read the byte in the receive data register before
the next full byte enters the shift register. In an overflow condition, the byte already in the receive data
register is unaffected, and the byte that shifted in last is lost. Clear the OVRF bit by reading the SPI
status and control register with OVRF set and then reading the receive data register. Reset clears the
OVRF bit.
This clearable, read-only flag is set in a slave SPI if the SS pin goes high during a transmission with
MODFEN set. In a master SPI, the MODF flag is set if the SS pin goes low at any time with the
MODFEN bit set. Clear MODF by reading the SPI status and control register (SPSCR) with MODF set
and then writing to the SPI control register (SPCR). Reset clears the MODF bit.
This clearable, read-only flag is set each time the transmit data register transfers a byte into the shift
register. SPTE generates an SPTE CPU interrupt request if SPTIE in the SPI control register is set
also.
During an SPTE CPU interrupt, the CPU clears SPTE by writing to the transmit data register.
Reset sets the SPTE bit.
This read/write bit, when set, allows the MODF flag to be set. If the MODF flag is set, clearing MODFEN
does not clear the MODF flag. If the SPI is enabled as a master and the MODFEN bit is 0, then the SS
pin is available as a general-purpose I/O.
If the MODFEN bit is 1, then the SS pin is not available as a general-purpose I/O. When the SPI is
enabled as a slave, the SS pin is not available as a general-purpose I/O regardless of the value of
MODFEN. See
If the MODFEN bit is 0, the level of the SS pin does not affect the operation of an enabled SPI
configured as a master. For an enabled SPI configured as a slave, having MODFEN low only prevents
the MODF flag from being set. It does not affect any other part of SPI operation. See
Error.
1 = MODF and OVRF can generate CPU interrupt requests
0 = MODF and OVRF cannot generate CPU interrupt requests
1 = Overflow
0 = No overflow
1 = SS pin at inappropriate logic level
0 = SS pin at appropriate logic level
1 = Transmit data register empty
0 = Transmit data register not empty
Do not write to the SPI data register unless SPTE is high.
16.11.4 SS (Slave Select).
MC68HC908GT16 • MC68HC908GT8 • MC68HC08GT16 Data Sheet, Rev. 5.0
NOTE
16.6.2 Mode Fault
I/O Registers
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