ST72F264G ST Microelectronics, ST72F264G Datasheet - Page 82

• Manufacturer Part Number: ST72F264G
• Description: (ST72F260G - ST72F264G) 8-BIT MCU
• Manufacturer: ST Microelectronics

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ST72260G, ST72262G, ST72264G
SERIAL PERIPHERAL INTERFACE (Cont’d)
11.4.8 Register Description
CONTROL REGISTER (SPICR)
Read/Write
Reset Value: 0000 xxxx (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 an End
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
(MODF)" on page
reset, so the SPI peripheral is not initially connect-
ed to the external pins.
0: I/O pins free for general purpose I/O
1: SPI I/O pin alternate functions enabled
Bit 5 = SPR2 Divider Enable .
This bit is set and cleared by software and is
cleared by reset. It is used with the SPR[1:0] bits to
set the baud rate. Refer to
mode SCK
0: Divider by 2 enabled
1: Divider by 2 disabled
Note: This bit has no effect in slave mode.
Bit 4 = MSTR Master Mode.
This bit is set and cleared by software. It is also
cleared by hardware when, in master mode, SS=0
(see
(MODF)" on page
0: Slave mode
1: Master mode. The function of the SCK pin
82/171
SPIE SPE SPR2
of Transfer event, Master Mode Fault or Over-
run error occurs (SPIF=1, MODF=1 or OVR=1
in the SPICSR register)
changes from an input to an output and the func-
tions of the MISO and MOSI pins are reversed.
7
4
U
Section 11.4.5.1 "Master Mode Fault
Section 11.4.5.1 "Master Mode Fault
.com
Frequency.
MSTR
79).
79). The SPE bit is cleared by
CPOL
Table 16 SPI Master
CPHA
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SPR1
SPR0
0
Bit 3 = CPOL Clock Polarity.
This bit is set and cleared by software. This bit de-
termines the idle state of the serial Clock. The
CPOL bit affects both the master and slave
modes.
0: SCK pin has a low level idle state
1: SCK pin has a high level idle state
Note: If CPOL is changed at the communication
byte boundaries, the SPI must be disabled by re-
setting the SPE bit.
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
Note: The slave must have the same CPOL and
CPHA settings as the master.
Bits 1:0 = SPR[1:0] Serial Clock Frequency.
These bits are set and cleared by software. Used
with the SPR2 bit, they select the baud rate of the
SPI serial clock SCK output by the SPI in master
mode.
Note: These 2 bits have no effect in slave mode.
Table 16. SPI Master mode SCK Frequency
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
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SPR1
0
0
0
1
1
1
SPR0
0
0
1
0
0
1
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