80 lines
2.2 KiB
Text
80 lines
2.2 KiB
Text
.program atkbd
|
|
.pio_version 0
|
|
.in 32 right auto
|
|
;.out 2 left auto
|
|
;.set 2
|
|
;; todo: use 'wait gpio' (or 'wait jmp' [rp2350]) so any pair of pins
|
|
;; can be used
|
|
;wait 1 pin 1 ; wait for keyboard to signal ready (not necessary?)
|
|
|
|
.wrap_target
|
|
start:
|
|
jmp !osre send_byte ; if a byte is pending to send, do that
|
|
jmp pin start ; otherwise wait for keyboard to send something
|
|
|
|
; keyboard has signaled start condition
|
|
set x 9 ; will receive 10 bits (data + parity + stop)
|
|
wait 1 pin 1 ; wait for clock pin to go high (discard start bit)
|
|
|
|
receive_bit:
|
|
wait 0 pin 1
|
|
in pins 1
|
|
wait 1 pin 1
|
|
jmp x-- receive_bit
|
|
|
|
jmp start
|
|
|
|
send_byte:
|
|
set pins 0 ; will be pulling lines low selectively
|
|
set pindirs 2 [31] ; pull clock low to request to send
|
|
set pindirs 1 ; set data pin to output & send "R" bit
|
|
set x 8 ; will send 9 bits (data + parity)
|
|
|
|
send_bit:
|
|
wait 0 pin 1
|
|
out pins 1
|
|
wait 1 pin 1
|
|
jmp x-- send_bit
|
|
|
|
set pindirs 0 ; pins back to input mode
|
|
wait 0 pin 0
|
|
wait 1 pin 0 ; wait for keyboard ACK
|
|
.wrap
|
|
|
|
|
|
% c-sdk {
|
|
#include "keyboard.h"
|
|
#include "hardware/clocks.h"
|
|
void atkbd_program_init(PIO pio, int sm, int offset, int base_pin) {
|
|
pio_sm_config c = atkbd_program_get_default_config(offset);
|
|
|
|
sm_config_set_in_pins(&c, base_pin);
|
|
sm_config_set_in_shift(&c, /* shift right*/ 1, /* auto */ 1, /* N */ 10);
|
|
|
|
sm_config_set_out_pins(&c, base_pin, 2);
|
|
sm_config_set_out_shift(&c, /* shift right */ 1, /* auto */ 1, /* N */ 9);
|
|
|
|
sm_config_set_set_pins(&c, base_pin, 2);
|
|
|
|
sm_config_set_jmp_pin(&c, base_pin + 1);
|
|
|
|
sm_config_set_clkdiv(&c, clock_get_hz(clk_sys) / 100000); // 300kHz
|
|
|
|
// Set this pin's GPIO function (connect PIO to the pad)
|
|
pio_gpio_init(pio, base_pin);
|
|
pio_gpio_init(pio, base_pin+1);
|
|
|
|
// make sure the pins are initially inputs
|
|
pio_sm_set_consecutive_pindirs(pio, sm, base_pin, 2, false);
|
|
|
|
// Load our configuration, and jump to the start of the program
|
|
pio_sm_init(pio, sm, offset, &c);
|
|
|
|
// let's clear out anything that was pending
|
|
pio_sm_clear_fifos(pio, sm);
|
|
|
|
// Set the state machine running
|
|
pio_sm_set_enabled(pio, sm, true);
|
|
}
|
|
|
|
%}
|