MC68908GZ8MFAE Freescale Semiconductor, MC68908GZ8MFAE Datasheet - Page 241

• Manufacturer Part Number: MC68908GZ8MFAE
• Description: IC MCU 8BIT 8K FLASH 48-LQFP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68908GZ8MFAE

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: CAN, LIN, SCI, SPI
• Peripherals: LVD, POR, PWM
• Number Of I /o: 37
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 48-LQFP
• Processor Series: M689xx
• Core: HC08
• Data Bus Width: 8 bit
• Data Ram Size: 1 KB
• Interface Type: SPI, SCI, CAN
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 37
• Number Of Timers: 2
• Operating Supply Voltage: 5.5 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Development Tools By Supplier: FSICEBASE, M68CBL05AE, DEMO908GZ60E, M68EML08GZE
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 16 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

In this case, an overflow can be missed easily. Since no more SPRF interrupts can be generated until this
OVRF is serviced, it is not obvious that bytes are being lost as more transmissions are completed. To
prevent this, either enable the OVRF interrupt or do another read of the SPSCR following the read of the
SPDR. This ensures that the OVRF was not set before the SPRF was cleared and that future
transmissions can set the SPRF bit.
SPSCR read, enable the OVRF to the CPU by setting the ERRIE bit.
17.7.2 Mode Fault Error
Setting the SPMSTR bit selects master mode and configures the SPSCK and MOSI pins as outputs and
the MISO pin as an input. Clearing SPMSTR selects slave mode and configures the SPSCK and MOSI
pins as inputs and the MISO pin as an output. The mode fault bit, MODF, becomes set any time the state
of the slave select pin, SS, is inconsistent with the mode selected by SPMSTR.
To prevent SPI pin contention and damage to the MCU, a mode fault error occurs if:
For the MODF flag to be set, the mode fault error enable bit (MODFEN) must be set. Clearing the
MODFEN bit does not clear the MODF flag but does prevent MODF from being set again after MODF is
cleared.
Freescale Semiconductor
•
•
The SS pin of a slave SPI goes high during a transmission
The SS pin of a master SPI goes low at any time
SPI RECEIVE
COMPLETE
Figure 17-11. Clearing SPRF When OVRF Interrupt Is Not Enabled
SPSCR
OVRF
READ
READ
SPDR
SPRF
1
2
3
4
5
6
7
BYTE 1
BYTE 2 SETS SPRF BIT.
CPU READS SPSCR WITH SPRF BIT SET
AND OVRF BIT CLEAR.
BYTE 3 SETS OVRF BIT. BYTE 3 IS LOST.
BYTE 1 SETS SPRF BIT.
CPU READS SPSCR WITH SPRF BIT SET
AND OVRF BIT CLEAR.
CPU READS BYTE 1 IN SPDR,
CLEARING SPRF BIT.
CPU READS SPSCR AGAIN
TO CHECK OVRF BIT.
1
MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 4
2
Figure 17-11
3
4
BYTE 2
5
illustrates this process. Generally, to avoid this second
BYTE 3
6
7
8
10
11
12
13
14
8
9
CPU READS SPSCR AGAIN
TO CHECK OVRF BIT.
CPU READS BYTE 2 SPDR,
CLEARING OVRF BIT.
BYTE 4 SETS SPRF BIT.
CPU READS SPSCR.
CPU READS BYTE 4 IN SPDR,
CLEARING SPRF BIT.
CPU READS SPSCR AGAIN
TO CHECK OVRF BIT.
CPU READS BYTE 2 IN SPDR,
CLEARING SPRF BIT.
9
BYTE 4
10
11
12
13
14
Error Conditions
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