MC68HC908GP16CFB Freescale Semiconductor, MC68HC908GP16CFB Datasheet - Page 181

• Manufacturer Part Number: MC68HC908GP16CFB
• Description: MCU 8-BIT 16K FLASH 44-QFP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908GP16CFB

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: SCI, SPI
• Peripherals: LVD, POR, PWM
• Number Of I /o: 33
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-QFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

15.9 Resetting the SPI
Any system reset completely resets the SPI. Partial reset occurs whenever the SPI enable bit (SPE) is
low. Whenever SPE is low, the following occurs:
The following additional 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 reset all control bits when SPE is set back to 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 a 0 to the SPE bit. The SPI also can be
disabled by a mode fault occurring in an SPI that was configured as a master with the MODFEN bit set.
Freescale Semiconductor
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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
SPSCK (CPHA:CPOL = 1:0)
WRITE TO SPDR
READ SPSCR
READ SPDR
1
2
3
4
5
6
SPRF
CPU WRITES BYTE 1 TO SPDR, CLEARING
SPTE BIT.
BYTE 1 TRANSFERS FROM TRANSMIT DATA
REGISTER TO SHIFT REGISTER, SETTING SPTE BIT.
CPU WRITES BYTE 2 TO SPDR, QUEUEING
BYTE 2 AND CLEARING SPTE BIT.
FIRST INCOMING BYTE TRANSFERS FROM SHIFT
REGISTER TO RECEIVE DATA REGISTER, SETTING
SPRF BIT.
BYTE 2 TRANSFERS FROM TRANSMIT DATA
REGISTER TO SHIFT REGISTER, SETTING SPTE BIT.
CPU READS SPSCR WITH SPRF BIT SET.
SPTE
MOSI
1
Figure 15-10. SPRF/SPTE CPU Interrupt Timing
MC68HC908EY16 • MC68HC908EY8 Data Sheet, Rev. 10
MSB BIT
BYTE 1
2
6
BIT
5
3
BIT
4
BIT
3
BIT
2
BIT
1
10
11 CPU READS SPSCR WITH SPRF BIT SET.
12 CPU READS SPDR, CLEARING SPRF BIT.
7
8
9
LSB MSB BIT
5
4
CPU READS SPDR, CLEARING SPRF BIT.
CPU WRITES BYTE 3 TO SPDR, QUEUEING
BYTE 3 AND CLEARING SPTE BIT.
SECOND INCOMING BYTE TRANSFERS FROM SHIFT
REGISTER TO RECEIVE DATA REGISTER, SETTING
SPRF BIT.
BYTE 3 TRANSFERS FROM TRANSMIT DATA
REGISTER TO SHIFT REGISTER, SETTING SPTE BIT.
BYTE 2
6
6
7
BIT
5
8
BIT
4
BIT
3
BIT
2
BIT
1
LSB MSB BIT
10
9
BYTE 3
11
Resetting the SPI
6
12
BIT
5
BIT
4
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