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8271D–AVR–05/11
ATmega48A/PA/88A/PA/168A/PA/328/P
19.5.3
SPDR – SPI Data Register
The SPI Data Register is a read/write register used for data transfer between the Register File
and the SPI Shift Register. Writing to the register initiates data transmission. Reading the regis-
ter causes the Shift Register Receive buffer to be read.
Bit
7
6
5
4
3
2
1
0
MSB
LSB
SPDR
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial Value
X
X
X
X
X
X
X
X
Undefined