CRTC sampling and output on VGA.

main
giomba 2022-12-08 15:14:34 +01:00
parent ac3116a339
commit a38a0c5b70
6 changed files with 225 additions and 4 deletions

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@ -17,6 +17,7 @@ add_compile_options(-Wall
)
add_executable(ceda2vga
src/crtc.c
src/main.c
src/draw_demo.c
src/framebuffer.c
@ -27,6 +28,10 @@ pico_generate_pio_header(ceda2vga
${CMAKE_CURRENT_LIST_DIR}/src/vga.pio
)
pico_generate_pio_header(ceda2vga
${CMAKE_CURRENT_LIST_DIR}/src/crtc.pio
)
# configure stdio to make I/O on virtual usb serial port
pico_enable_stdio_usb(ceda2vga 1)
pico_enable_stdio_uart(ceda2vga 0)

148
src/crtc.c Normal file
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@ -0,0 +1,148 @@
#include "crtc.h"
#include <stdio.h>
#include "hardware/pio.h"
#include "hardware/structs/pio.h"
#include "hardware/dma.h"
#include "framebuffer.h"
#include "crtc.pio.h"
typedef struct PIORun
{
PIO pio; //< executing PIO
uint offset; //< PIO memory offset for program
uint sm; //< executing SM
} PIORun;
static PIORun crtc_vsync, crtc_hsync, crtc_pixel;
static int dma_channel;
bool dma_ready = false;
static void crtc_pixel_program_init(PIO pio, uint sm, uint offset)
{
pio_sm_config config = crtc_pixel_program_get_default_config(offset);
pio_gpio_init(pio, 11);
sm_config_set_in_pins(&config, 11);
sm_config_set_in_shift(&config, true, true, 0);
pio_sm_set_consecutive_pindirs(pio, sm, 11, 1, false);
sm_config_set_wrap(&config, offset + crtc_pixel_wrap_target, offset + crtc_pixel_wrap);
pio_sm_init(pio, sm, offset, &config);
// not quite 4x pixel clock (2.1 = 2,25.6)
pio_sm_set_clkdiv_int_frac(pio, sm, 2, 26);
pio_sm_set_enabled(pio, sm, true);
}
static void crtc_hsync_program_init(PIO pio, uint sm, uint offset)
{
pio_sm_config config = crtc_hsync_program_get_default_config(offset);
sm_config_set_wrap(&config, offset + crtc_hsync_wrap_target, offset + crtc_hsync_wrap);
pio_sm_init(pio, sm, offset, &config);
pio_sm_set_clkdiv_int_frac(pio, sm, 2, 26);
pio_sm_set_enabled(pio, sm, true);
}
static void crtc_vsync_program_init(PIO pio, uint sm, uint offset)
{
pio_sm_config config = crtc_vsync_program_get_default_config(offset);
pio_gpio_init(pio, 15);
sm_config_set_wrap(&config, offset + crtc_vsync_wrap_target, offset + crtc_vsync_wrap);
pio_sm_init(pio, sm, offset, &config);
pio_sm_set_clkdiv_int_frac(pio, sm, 2, 26);
pio_sm_set_enabled(pio, sm, true);
}
int dma_counter = 0;
static void dma_handler(void)
{
dma_counter++;
// reset DMA
dma_channel_set_write_addr(dma_channel, &frame[2560], true);
// acknoweledge DMA
dma_hw->ints1 = 1 << dma_channel;
}
int crtc_frame_counter = 0;
static void new_frame_handler(void)
{
pio_sm_clear_fifos(crtc_pixel.pio, crtc_pixel.sm);
crtc_frame_counter++;
pio_interrupt_clear(pio1_hw, 1);
}
void crtc_machines_init(void)
{
crtc_hsync.pio = crtc_vsync.pio = crtc_pixel.pio = pio1;
printf("Starting CRTC pixel machine... ");
if (!pio_can_add_program(crtc_pixel.pio, &crtc_pixel_program))
panic("cannot add program");
crtc_pixel.offset = pio_add_program(crtc_pixel.pio, &crtc_pixel_program);
crtc_pixel.sm = pio_claim_unused_sm(crtc_pixel.pio, true);
crtc_pixel_program_init(crtc_pixel.pio, crtc_pixel.sm, crtc_pixel.offset);
pio_sm_put_blocking(crtc_pixel.pio, crtc_pixel.sm, 640 - 1);
printf("OK\n");
printf("Starting CRTC vsync machine... ");
if (!pio_can_add_program(crtc_vsync.pio, &crtc_vsync_program))
panic("cannot add program");
crtc_vsync.offset = pio_add_program(crtc_vsync.pio, &crtc_vsync_program);
crtc_vsync.sm = pio_claim_unused_sm(crtc_vsync.pio, true);
crtc_vsync_program_init(crtc_vsync.pio, crtc_vsync.sm, crtc_vsync.offset);
printf("OK\n");
printf("Starting CRTC hsync machine... ");
if (!pio_can_add_program(crtc_hsync.pio, &crtc_hsync_program))
panic("cannot add program");
crtc_hsync.offset = pio_add_program(crtc_hsync.pio, &crtc_hsync_program);
crtc_hsync.sm = pio_claim_unused_sm(crtc_hsync.pio, true);
crtc_hsync_program_init(crtc_hsync.pio, crtc_hsync.sm, crtc_hsync.offset);
pio_sm_put_blocking(crtc_hsync.pio, crtc_hsync.sm, 128 - 1);
printf("OK\n");
printf("Setting up new frame interrupt... ");
// Frame interrupt is asserted on PIO1 interrupt 1 by SM1
pio_set_irq1_source_enabled(crtc_vsync.pio, pis_interrupt1,
true); // allow SM1 of PIO to fire the interrupt
irq_set_exclusive_handler(PIO1_IRQ_1, new_frame_handler); // set handler for IRQ1 of PIO
irq_set_enabled(PIO1_IRQ_1, true); // enable interrupt
printf("OK\n");
printf("Setting up CRTC DMA... ");
dma_channel = dma_claim_unused_channel(true);
printf("channel %d... ", dma_channel);
dma_channel_config dma_config = dma_channel_get_default_config(dma_channel);
channel_config_set_transfer_data_size(&dma_config, DMA_SIZE_32);
channel_config_set_read_increment(&dma_config, false);
channel_config_set_write_increment(&dma_config, true);
channel_config_set_dreq(&dma_config, DREQ_PIO1_RX0);
// setup transfer acknowledge interrupt
dma_channel_set_irq1_enabled(dma_channel, true);
irq_set_exclusive_handler(DMA_IRQ_1, dma_handler);
irq_set_enabled(DMA_IRQ_1, true);
dma_channel_configure(dma_channel, &dma_config, &frame[2560], &pio1_hw->rxf[0], 640 * 128 / 32,
true);
dma_ready = true;
printf("OK\n");
}

6
src/crtc.h Normal file
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@ -0,0 +1,6 @@
#ifndef CRTC_H
#define CRTC_H
void crtc_machines_init(void);
#endif

37
src/crtc.pio Normal file
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@ -0,0 +1,37 @@
.program crtc_pixel
entrypoint_crtc_pixel:
pull
.wrap_target
mov y, osr
wait irq 6
visible_line_loop:
in pins, 1 [2]
jmp y-- visible_line_loop
.wrap
.program crtc_hsync
pull
.wrap_target
mov y, osr
wait irq 1
scanlines_loop:
set x, 7
wait 1 gpio 14
wait 0 gpio 14
back_porch_loop:
jmp x-- back_porch_loop [31]
irq set 6
jmp y-- scanlines_loop
.wrap
.program crtc_vsync
entrypoint_ceda_crt_vsync:
.wrap_target
wait 0 gpio 15
wait 1 gpio 15
irq set 1
.wrap

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@ -17,15 +17,42 @@
#include "draw_demo.h"
#include "framebuffer.h"
#include "vga.h"
#include "crtc.h"
extern int crtc_frame_counter;
extern int dma_counter;
int main()
{
stdio_init_all();
sleep_ms(5000);
draw_demo();
// draw_demo();
// horizontal lines
draw_line(0, 0, 640 - 1, 0, true);
draw_line(0, 240 - 1, 640 - 1, 240 - 1, true);
draw_line(0, 480 - 1, 640 - 1, 480 - 1, true);
// vertical lines
draw_line(0, 0, 0, 480 - 1, true);
draw_line(320 - 1, 0, 320 - 1, 480 - 1, true);
draw_line(638, 0, 638, 480 - 1, true); // last pixel of a line can't be set, see set_pixel()
vga_machines_init();
sleep_ms(10);
crtc_machines_init();
printf("All ready: OK\n");
for (;;)
{
printf("CRTC frames: %d\n", crtc_frame_counter);
printf("DMA counter: %d\n", dma_counter);
sleep_ms(1000);
}
for (;;)
{
// moving sine

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@ -237,7 +237,7 @@ void vga_machines_init(void)
pio_sm_put_blocking(vga_pixel.pio, vga_pixel.sm, 640 - 1);
printf("OK\n");
printf("Setting up DMA... ");
printf("Setting up VGA DMA... ");
dma_channel = dma_claim_unused_channel(true);
dma_channel_config dma_config = dma_channel_get_default_config(dma_channel);
channel_config_set_transfer_data_size(&dma_config, DMA_SIZE_32);
@ -260,8 +260,6 @@ void vga_machines_init(void)
dma_ready = true;
printf("OK\n");
printf("Now running.\n");
}
/**