ATMEGA644P-20PQ Atmel, ATMEGA644P-20PQ Datasheet - Page 163

• Manufacturer Part Number: ATMEGA644P-20PQ
• Description: MCU AVR 64K FLASH 20MHZ 40-PDIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644P-20PQ

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8011O–AVR–07/10
When the SPI is enabled, the data direction of the MOSI, MISO, SCK, and SS pins is overridden
according to
Functions” on page
Table 15-1.
Note:
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 PB5, replace
DD_MOSI with DDB5 and DDR_SPI with DDRB.
MOSI
MISO
SCK
Pin
SS
1. See
direction of the user defined SPI pins.
Table
SPI Pin Overrides
”Alternate Functions of Port B” on page 82
Direction, Master SPI
User Defined
Input
User Defined
User Defined
15-1. For more details on automatic port overrides, refer to
78.
(1)
ATmega164P/324P/644P
for a detailed description of how to define the
Direction, Slave SPI
Input
User Defined
Input
Input
”Alternate Port
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