spi_init
	outa, spi_ss
	dira, spi_out

spi_init_ret
	ret

spi_write
	mov spi_bits, #8	' 8 bits zu schieben
	shl spi_byte, #24	' ganz nach links, um ueber C raus
:next   
	shl spi_byte, #1 wc	' msb -> C
	muxc outa, spi_mosi	' C -> MOSI
	or outa, spi_sclk	' Takt hoch
	andn outa, spi_sclk	' Takt runter
	djnz spi_bits, #:next

	andn outa, spi_mosi	' falls lsb=1

spi_write_ret
	ret

' Pins
spi_sclk	long SPI_SCLK
spi_mosi	long SPI_MOSI
spi_miso	long SPI_MISO
spi_ss		long SPI_SS
spi_out		long SPI_SCLK|SPI_MOSI|SPI_SS

' Speicher
spi_bits	res 1
spi_byte	res 1