Atmel ATmega48PV User Manual

170
8025I–AVR–02/09
ATmega48P/88P/168P/328P
The following code examples show how to initialize the SPI as a Slave and how to perform a
simple reception.
Note: 1. See ”Code Examples” on page 7.
Assembly Code Example
(1)
SPI_SlaveInit:
; Set MISO output, all others input
ldi r17,(1<<DD_MISO)
out DDR_SPI,r17
; Enable SPI
ldi r17,(1<<SPE)
out SPCR,r17
ret
SPI_SlaveReceive:
; Wait for reception complete
sbis SPSR,SPIF
rjmp SPI_SlaveReceive
; Read received data and return
in r16,SPDR
ret
C Code Example
(1)
void SPI_SlaveInit(void)
{
/* Set MISO output, all others input */
DDR_SPI = (1<<DD_MISO);
/* Enable SPI */
SPCR = (1<<SPE);
}
char SPI_SlaveReceive(void)
{
/* Wait for reception complete */
while(!(SPSR & (1<<SPIF)))
;
/* Return Data Register */
return SPDR;
}

Atmel ATmega48PV Specifications

General

Architecture	8-bit AVR
Operating Voltage	1.8V - 5.5V
Flash Memory	4 KB
SRAM	512 Bytes
EEPROM	256 Bytes
Clock Speed	0 - 20 MHz
I/O Pins	23
ADC Channels	6
ADC Resolution	10-bit
PWM Channels	6
Operating Temperature	-40°C to 85°C
Serial Interfaces	USART, SPI, I2C
Package Options	MLF
Timers/Counters	Two 8-bit Timers/Counters, One 16-bit Timer/Counter