123
8008H–AVR–04/11
ATtiny48/88
Note:
The following code examples show how to initialize the SPI as a Slave and how to perform a
simple reception.
Note:
C Code Example
void
SPI_MasterInit(void)
{
/* Set MOSI and SCK output, all others input */
DDR_SPI = (1<<DD_MOSI)|(1<<DD_SCK);
/* Enable SPI, Master, set clock rate fck/16 */
SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0);
}
void
SPI_MasterTransmit(char cData)
{
/* Start transmission */
SPDR = cData;
/* Wait for transmission complete */
while
(!(SPSR & (1<<SPIF)))
;
}
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