ST72T331 STMICROELECTRONICS [STMicroelectronics], ST72T331 Datasheet - Page 80

• Manufacturer Part Number: ST72T331
• Description: 8-BIT MCU WITH 8 TO 16K OTP/EPROM, 256 EEPROM, 384 TO 512 BYTES RAM, ADC, WDG, SCI, SPI AND 2 TIMERS
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST72E331 ST72T331
SERIAL PERIPHERAL INTERFACE (Cont’d)
5.6.7 Register Description
CONTROL REGISTER (CR)
Read/Write
Reset Value: 0000xxxx (0xh)
Bit 7 = SPIE Serial peripheral interrupt enable.
This bit is set and cleared by software.
0: Interrupt is inhibited
1: An SPI interrupt is generated whenever SPIF=1
Bit 6 = SPE Serial peripheral output enable.
This bit is set and cleared by software. It is also
cleared by hardware when, in master mode, SS=0
(see
0: I/O port connected to pins
1: SPI alternate functions connected to pins
The SPE bit is cleared by reset, so the SPI periph-
eral is not initially connected to the external pins.
Bit 5 = SPR2 Divider Enable .
this bit is set and cleared by software and it is
cleared by reset. It is used with the SPR[1:0] bits to
set the baud rate. Refer to
0: Divider by 2 enabled
1: Divider by 2 disabled
Bit 4 = MSTR Master.
This bit is set and cleared by software. It is also
cleared by hardware when, in master mode, SS=0
(see
0: Slave mode is selected
1: Master mode is selected, the function of the
80/107
80
SPIE
or MODF=1 in the SR register
7
SCK pin changes from an input to an output and
the functions of the MISO and MOSI pins are re-
versed.
Section 0.1.4.5 Master Mode
Section 0.1.4.5 Master Mode
SPE SPR2
MSTR
CPOL
Table
CPHA
1.
Fault).
Fault).
SPR1
SPR0
0
Bit 3 = CPOL Clock polarity.
This bit is set and cleared by software. This bit de-
termines the steady state of the serial Clock. The
CPOL bit affects both the master and slave
modes.
0: The steady state is a low value at the SCK pin.
1: The steady state is a high value at the SCK pin.
Bit 2 = CPHA Clock phase.
This bit is set and cleared by software.
0: The first clock transition is the first data capture
1: The second clock transition is the first capture
Bit 1:0 = SPR[1:0] Serial peripheral rate.
These bits are set and cleared by software.Used
with the SPR2 bit, they select one of six baud rates
to be used as the serial clock when the device is a
master.
These 2 bits have no effect in slave mode.
Table 18. Serial Peripheral Baud Rate
edge.
edge.
Serial Clock
f
f
f
f
CPU
f
f
CPU
CPU
CPU
CPU
CPU
/128
/16
/32
/64
/4
/8
SPR2
1
0
0
1
0
0
SPR1
0
0
0
1
1
1
SPR0
0
0
1
0
0
1