Data I/O Register (Spidr); Table 59. Spi Register Map And Reset Values - STMicroelectronics ST72361 Auto Series Manual

ST72361xx-Auto
14.8.3

Data I/O register (SPIDR)

Read/ write
Reset value: Undefined
7
D7
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.
Note: 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 read to the SPIDR register returns the value located in the buffer and not the content of
the shift register (see
Table 59.
Address
(Hex.)
21
22
23
D6 D5
A write to the SPIDR register places data directly into the
shift register for transmission.
Figure 70).
SPI register map and reset values
Register label 7
SPIDR MSB
Reset value x
SPICR SPIE
Reset value 0
SPICSR SPIF
Reset value 0
Doc ID 12468 Rev 3
Serial peripheral interface (SPI)
D4 D3
6 5 4
x x x
SPE SPR2 MSTR
0 0 0
WCOL OVR MODF
0 0 0
D2 D1
3 2 1
x x x
CPOL CPHA SPR1
x x x
SOD SSM
0 0 0
0
D0
0
LSB
x
SPR0
x
SSI
0
155/279