Rainbow Electronics ATmega64M1 - Manual (Page 157)

157
8209A–AVR–08/09
ATmega16M1/32M1/64M1
Note: 1. The example code assumes that the part specific header file is included.
The following code examples show how to initialize the SPI as a Slave and how to perform a
simple reception.
Assembly Code Example (1)
SPI_MasterInit:
; Set MOSI and SCK output, all others input
ldi r17,(1<
out DDR_SPI,r17
; Enable SPI, Master, set clock rate fck/16
ldi r17,(1<
out SPCR,r17
ret
SPI_MasterTransmit:
; Start transmission of data (r16)
out SPDR,r16
Wait_Transmit:
; Wait for transmission complete
sbis SPSR,SPIF
rjmp Wait_Transmit
ret
C Code Example (1)
void SPI_MasterInit(void)
{
/* Set MOSI and SCK output, all others input */
DDR_SPI = (1<
/* Enable SPI, Master, set clock rate fck/16 */
SPCR = (1<
}
void SPI_MasterTransmit(char cData)
{
/* Start transmission */
SPDR = cData;
/* Wait for transmission complete */
while (!(SPSR & (1<
;
}