REGISTER SUMMARY
M68HC16 Z SERIES
D-64
USER’S MANUAL
D.7.13 SPI Control Register
The SPCR contains parameters for configuring the SPI. The register can be read or
written at any time.
SPIE — SPI Interrupt Enable
0 = SPI interrupts disabled.
1 = SPI interrupts enabled.
SPE — SPI Enable
0 = SPI is disabled.
1 = SPI is enabled.
WOMP — Wired-OR Mode for SPI Pins
0 = Outputs have normal CMOS drivers.
1 = Pins designated for output by MDDR have open-drain drivers, regardless of
whether the pins are used as SPI outputs or for general-purpose I/O, and re-
gardless of whether the SPI is enabled.
MSTR — Master/Slave Mode Select
0 = SPI is a slave device.
1 = SPI is system master.
CPOL — Clock Polarity
0 = The inactive state value of SCK is logic level zero.
1 = The inactive state value of SCK is logic level one.
CPOL is used to determine the inactive state of the serial clock (SCK). It is used with
CPHA to produce a desired clock/data relationship between master and slave devices.
CPHA — Clock Phase
0 = Data captured on the leading edge of SCK and changed on the trailing edge of
SCK.
1 = Data is changed on the leading edge of SCK and captured on the trailing edge
of SCK.
CPHA determines which edge of SCK causes data to change and which edge causes
data to be captured. CPHA is used with CPOL to produce a desired clock/data rela-
tionship between master and slave devices.
LSBF — Least Significant Bit First
0 = Serial data transfer starts with LSB.
1 = Serial data transfer starts with MSB.
SPCR — SPI Control Register
$YFFC38
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SPIE
SPE
WOMP
MSTR
CPOL
CPHA
LSBF
SIZE
SPBR[7:0]
RESET:
0
0
0
0
0
0
0
1
0
0
0
0
0
1
0
0
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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