ATMEGA8U2_14 Datasheet, PDF (140/310 Pages) ATMEL Corporation – 125 Powerful Instructions – Most Single Clock Cycle Execution

ATmega8U2/16U2/32U2
Functions” on page 72.
Table 17-1.
Pin
MOSI
MISO
SCK
SS
SPI Pin Overrides⁽¹⁾
Direction, Master SPI
User Defined
Input
User Defined
User Defined
Direction, Slave SPI
Input
User Defined
Input
Input
Note: 1. See “Alternate Functions of Port B” on page 74 for a detailed description of how to define the
direction of the user defined SPI pins.
The following code examples show how to initialize the SPI as a Master and how to perform a
simple transmission. DDR_SPI in the examples must be replaced by the actual Data Direction
Register controlling the SPI pins. DD_MOSI, DD_MISO and DD_SCK must be replaced by the
actual data direction bits for these pins. E.g. if MOSI is placed on pin PB5, replace DD_MOSI
with DDB5 and DDR_SPI with DDRB.
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