ST72561AR7 STMicroelectronics, ST72561AR7 Datasheet - Page 120

• Manufacturer Part Number: ST72561AR7
• Description: 8-bit MCU
• Manufacturer: STMicroelectronics

Specifications of ST72561AR7

• Hdflash Endurance: 100 cycles, data retention 40 years at 85°C
• 5 Power Saving Modes: Halt, Auto Wake Up From Halt, Active Halt, Wait and Slow

ST72561
SERIAL PERIPHERAL INTERFACE (cont’d)
SPI CONTROL/STATUS REGISTER (SPICSR)
Read/Write (some bits Read Only)
Reset Value: 0000 0000 (00h)
Bit 7 = SPIF Serial Peripheral Data Transfer Flag
0: Data transfer is in progress or the flag has been
1: Data transfer between the device and an exter-
Note: While the SPIF bit is set, all writes to the
SPIDR register are inhibited until the SPICSR reg-
ister is read.
Bit 6 = WCOL Write Collision status (Read only)
This bit is set by hardware when a write to the
SPIDR register is done during a transmit se-
quence. It is cleared by a software sequence (see
Figure
0: No write collision occurred
1: A write collision has been detected
Bit 5 = OVR SPI Overrun error (Read only)
This bit is set by hardware when the byte currently
being received in the shift register is ready to be
transferred into the SPIDR register while SPIF = 1
(See
SPIE = 1 in the SPICR register. The OVR bit is
cleared by software reading the SPICSR register.
0: No overrun error
1: Overrun error detected
Bit 4 = MODF Mode Fault flag (Read only)
This bit is set by hardware when the SS pin is
pulled low in master mode (see
"Master Mode Fault
can be generated if SPIE = 1 in the SPICR regis-
ter. This bit is cleared by a software sequence (An
access to the SPICSR register while MODF = 1
followed by a write to the SPICR register).
0: No master mode fault detected
1: A fault in master mode has been detected
Bit 3 = Reserved, must be kept cleared.
120/265
SPIF
cleared.
nal device has been completed.
(Read only)
This bit is set by hardware when a transfer has
been completed. An interrupt is generated if
SPIE = 1 in the SPICR register. It is cleared by
a software sequence (an access to the SPICSR
register followed by a write or a read to the
SPIDR register).
7
Section
WCOL
75).
10.6.5.2). An interrupt is generated if
OVR
MODF
(MODF)"). An SPI interrupt
-
SOD
Section 10.6.5.1
SSM
SSI
0
Bit 2 = SOD SPI Output Disable
This bit is set and cleared by software. When set, it
disables the alternate function of the SPI output
(MOSI in master mode / MISO in slave mode)
0: SPI output enabled (if SPE = 1)
1: SPI output disabled
Bit 1 = SSM SS Management
This bit is set and cleared by software. When set, it
disables the alternate function of the SPI SS pin
and uses the SSI bit value instead. See
10.6.3.2 "Slave Select
0: Hardware management (SS managed by exter-
1: Software management (internal SS signal con-
Bit 0 = SSI SS Internal Mode
This bit is set and cleared by software. It acts as a
‘chip select’ by controlling the level of the SS slave
select signal when the SSM bit is set.
0: Slave selected
1: Slave deselected
SPI DATA I/O REGISTER (SPIDR)
Read/Write
Reset Value: Undefined
The SPIDR register is used to transmit and receive
data on the serial bus. In a master device, a write
to this register will initiate transmission/reception
of another byte.
Notes: During the last clock cycle the SPIF bit is
set, a copy of the received data byte in the shift
register is moved to a buffer. When the user reads
the serial peripheral data I/O register, the buffer is
actually being read.
While the SPIF bit is set, all writes to the SPIDR
register are inhibited until the SPICSR register is
read.
Warning: A write to the SPIDR register places
data directly into the shift register for transmission.
A read to the SPIDR register returns the value lo-
cated in the buffer and not the content of the shift
register (see
D7
nal pin)
trolled by SSI bit. External SS pin free for gener-
al-purpose I/O)
7
D6
Figure
D5
70).
D4
Management".
D3
D2
D1
Section
D0
0