rx-mosi.pio

; Sony MI-SPI state machine for decoding data in the MOSI direction
; (Reading data sent from a body to a flash)
; 2023/04 Andrew Villeneuve

; Pin mapping:
; IN 0 = DATA
; IN 1 = CLK
; Note that the physical wiring of these signals must be both consequtive and in this order

; The MOSI START pulse will have already been evaluated when the SM starts,
; so the first CLK pulse we see should be for a data bit

.program mosi

.wrap_target
	wait 1 pin 1			;wait for rising edge of clock (IN pin 1)
	wait 0 pin 1 			;wait for falling edge of clock (IN pin 1)
	in pins, 1 			    ;read the level of the DATA pin into the ISR
.wrap

% c-sdk {
static inline void mosi_program_init(PIO pio, uint sm, uint offset, uint datapin) {
    pio_sm_config c = mosi_program_get_default_config(offset);

    // Map IN_BASE to the DATA pin. The next pin sequentially must be CLOCK
    sm_config_set_in_pins(&c, datapin);

    // ISR Shift: shift right, autopush enabled, every 8 bits
    sm_config_set_in_shift(&c, true, true, 8);

    // Load our configuration, and jump to the start of the program
    pio_sm_init(pio, sm, offset, &c);
}
%}