ATMEGA644P-20PQ Atmel, ATMEGA644P-20PQ Datasheet - Page 161

• 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

15. SPI – Serial Peripheral Interface
15.1
15.2
8011O–AVR–07/10
Features
Overview
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The Serial Peripheral Interface (SPI) allows high-speed synchronous data transfer between the
ATmega164P/324P/644P and peripheral devices or between several AVR devices.
USART can also be used in Master SPI mode, see “USART in SPI Mode” on page 198.
The Power Reduction SPI bit, PRSPI, in
50 must be written to zero to enable SPI module.
Figure 15-1. SPI Block Diagram
Note:
Full-duplex, Three-wire Synchronous Data Transfer
Master or Slave Operation
LSB First or MSB First Data Transfer
Seven Programmable Bit Rates
End of Transmission Interrupt Flag
Write Collision Flag Protection
Wake-up from Idle Mode
Double Speed (CK/2) Master SPI Mode
1. Refer to
/2/4/8/16/32/64/128
DIVIDER
Figure 1-1 on page
(1)
2, and
”PRR – Power Reduction Register” on page 48
Table 11-6 on page 82
ATmega164P/324P/644P
for SPI pin placement.
on page
161