; PIO for an SPI interface running at CPUfreq/(2*12).  The code waits
; at .origin until it reads a value for y from the fifo a count of
; transfer y+1 bits have been read (should be a multiple of 8) and
; written. It then transfers that many bits of SPI data writing to the
; out pin and reading from the in pin. The side_set pin is used for
; the clock.

.program spi
.out 1 left auto 8
.in 1 left auto 8
.side_set 1
.origin
.wrap_target
	pull block	side 0
	out y, 32	side 0
loop:
	out pins, 1	side 0 [10]
	nop		side 1
	in pins, 1	side 1 [10]
	jmp y-- loop	side 0
.wrap