ATMEGA644A-AU Atmel, ATMEGA644A-AU Datasheet - Page 166

• Manufacturer Part Number: ATMEGA644A-AU
• Description: IC MCU AVR 64K FLASH 44TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644A-AU

• 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): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8272A–AVR–01/10
The following code examples show how to initialize the SPI as a Slave and how to perform a
simple reception.
Note:
164A/164PA/324A/324PA/644A/644PA/1284/1284P
Assembly Code Example
C Code Example
SPI_SlaveInit:
SPI_SlaveReceive:
void SPI_SlaveInit(void)
{
}
char SPI_SlaveReceive(void)
{
}
; Set MISO output, all others input
ldi
out
; Enable SPI
ldi
out
ret
; Wait for reception complete
sbis SPSR,SPIF
rjmp SPI_SlaveReceive
; Read received data and return
in
ret
/* Set MISO output, all others input */
DDR_SPI = (1<<DD_MISO);
/* Enable SPI */
SPCR = (1<<SPE);
/* Wait for reception complete */
while(!(SPSR & (1<<SPIF)))
/* Return Data Register */
return SPDR;
1. See “About Code Examples” on page 9.
;
r17,(1<<DD_MISO)
DDR_SPI,r17
r17,(1<<SPE)
SPCR,r17
r16,SPDR
(1)
(1)
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