mc68hc11f1cpu3 Freescale Semiconductor, Inc, mc68hc11f1cpu3 Datasheet - Page 104

• Manufacturer Part Number: mc68hc11f1cpu3
• Description: Mc68hc11f1 Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

SPIE — Serial Peripheral Interrupt Enable
SPE — Serial Peripheral System Enable
DWOM — Port D Wired-OR Mode
MSTR — Master Mode Select
CPOL — Clock Polarity
CPHA — Clock Phase
SPR[1:0] — SPI Clock Rate Selects
8-6
Set the SPE bit to one to request a hardware interrupt sequence each time the SPIF
or MODF status flag is set. SPI interrupts are inhibited if this bit is clear or if the I bit in
the condition code register is one.
When the SPE bit is set, the port D bit 2, 3, 4, and 5 pins are dedicated to the SPI func-
tion. If the SPI is in the master mode and DDRD bit 5 is set, then the port D bit 5 pin
becomes a general-purpose output instead of the SS input.
DWOM affects all port D pins.
When the clock polarity bit is cleared and data is not being transferred, the SCK pin of
the master device has a steady state low value. When CPOL is set, SCK idles high.
Refer to Figure 8-2 and 8.2.1 Clock Phase and Polarity Controls.
The clock phase bit, in conjunction with the CPOL bit, controls the clock-data relation-
ship between master and slave. The CPHA bit selects one of two different clocking
protocols. Refer to Figure 8-2 and 8.2.1 Clock Phase and Polarity Controls.
These two bits select the SPI clock (SCK) rate when the device is configured as mas-
ter. When the device is configured as slave, these bits have no effect. Refer to Table
8-1.
0 = SPI system interrupts disabled
1 = SPI system interrupts enabled
0 = SPI system disabled
1 = SPI system enabled
0 = Normal CMOS outputs
1 = Open-drain outputs
0 = Slave mode
1 = Master mode
SPR[1:0]
0 0
0 1
1 0
1 1
Divide By
E Clock
16
32
2
4
Freescale Semiconductor, Inc.
For More Information On This Product,
Frequency at
SERIAL PERIPHERAL INTERFACE
E = 2 MHz
62.5 kHz
1.0 MHz
500 kHz
125 kHz
Table 8-1 SPI Clock Rates
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Frequency at
E = 3 MHz
187.5 kHz
93.7 kHz
1.5 MHz
750 kHz
Frequency at
E = 4 MHz
2.0 MHz
1.0 MHz
250 kHz
125 kHz
Frequency at
TECHNICAL DATA
156.25 kHz
78.125 kHz
E = 5 MHz
2.5 MHz
625 kHz
MC68HC11F1