ATMEGA640 datasheet(201/449 Pages) ATMEL

Part #	ATMEGA640

Description	8-bit Microcontroller with 64K/128K/256K Bytes In-System Programmable Flash

PDF	449 Pages

Scroll/Zoom	100%

Manufacturer	ATMEL [ATMEL Corporation]

Direct Link	http://www.atmel.com

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201 / 449 page

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ATmega640/1280/1281/2560/2561

2549K–AVR–01/07

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

overridden according to Table 96. For more details on automatic port overrides, refer to

“Alternate Port Functions” on page 89.

Note:

1. See “Alternate Functions of Port B” on page 92 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 per-

form 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.

Table 96. SPI Pin Overrides

(1)

Direction, Master SPI

Direction, Slave SPI

MOSI

User Defined

Input

MISO

Input

User Defined

SCK

User Defined

Input

User Defined

Input

ATMEGA640 Datasheet(PDF) 201 Page - ATMEL Corporation