Datasheet

182

7734Q–AVR–02/12

AT90PWM81/161

When the SPI is enabled, the data direction of the MOSI, MISO, SCK, and SS pins is overridden

according to Table 14-1. For more details on automatic port overrides, refer to “Alternate Port

Functions” on page 73.

Note: 1. See “Alternate Functions of Port B” on page 75 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. For example, if MOSI is placed on pin PB2, replace DD_MOSI with DDB2 and

DDR_SPI with DDRB.

Table 14-1. SPI pin overrides

(1)

Pin Direction, Master SPI Direction, Slave SPI

MOSI User defined Input

MISO Input User defined

SCK User defined Input

User defined Input