timing.pio

;
; Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
;
; SPDX-License-Identifier: BSD-3-Clause
;

.program video_htiming
.side_set 1 ; used for clock
public entry_point:
    ; todo we can do this with one off setup via pio_exec
    pull block      side 0
.wrap_target
new_state:
    out exec, 16    side 1 ; this does any per state inline work (or it can be a JMP to entry_point to sleep..
                          ; note the EXECed instruction should have a side set 0
    out x, 13       side 1
    out pins, 3     side 0 ; we want an OUT EXEC above which sets an IRQ to start scanline output
                          ; to cause this out and the pixel out in the same cycle (this would be positive clk edge latch)
loop:
    nop             side 1
    jmp x-- loop    side 0
.wrap

; these are the values used in the out exec in video_htiming
.program video_htiming_states
.side_set 1
    ; state 0 = set irq 0
    irq 0           side 0
    ; state 1 = set irq 1
    irq 1           side 0
    ; state 2 = set irq 4
    irq 4           side 0
    ; state 3 = clear irq 4
    irq clear 4     side 0