files

Create LICENSE

CMakeLists.txt

@@ -1,42 +1,35 @@
 cmake_minimum_required(VERSION 3.13)
 
 set(CMAKE_C_STANDARD 11)
-set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
-# initalize pico_sdk from installed location
-# (note this can come from environment, CMake cache etc)
-set(PICO_SDK_PATH "/home/ben/pico/pico-sdk")
-
-# Pull in Raspberry Pi Pico SDK (must be before project)
+set(PICO_SDK_FETCH_FROM_GIT on)
 include(pico_sdk_import.cmake)
 
 project(pico_vga C CXX ASM)
 
-add_executable(pico_vga)
+include_directories(${CMAKE_SOURCE_DIR}/src)
+
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Werror -Wall -O2")
 
-# Initialise the Raspberry Pi Pico SDK
 pico_sdk_init()
 
+add_executable(pico_vga
+    src/main.c
+    src/vga.c
+)
 
-pico_set_program_name(pico_vga "pico_vga")
-pico_set_program_version(pico_vga "0.1")
-
-pico_enable_stdio_usb(pico_vga 1)
-pico_enable_stdio_uart(pico_vga 0)
-
-pico_generate_pio_header(pico_vga ${CMAKE_CURRENT_LIST_DIR}/video.pio)
-
-target_sources(pico_vga PRIVATE 
-    main.c
-    vga.c
-    )
-
-# Add the standard library to the build
 target_link_libraries(pico_vga
     pico_stdlib
     hardware_pio
     hardware_dma
     hardware_irq
-    )
+    hardware_clocks
+)
+
+pico_generate_pio_header(pico_vga ${CMAKE_CURRENT_LIST_DIR}/src/vga.pio)
+
+pico_enable_stdio_usb(pico_vga 1)
+pico_enable_stdio_uart(pico_vga 0)
 
 pico_add_extra_outputs(pico_vga)

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 Benjamin Kyd
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

designs/picovga/picovga.kicad_prl

@@ -2,10 +2,13 @@
   "board": {
     "active_layer": 0,
     "active_layer_preset": "",
+    "auto_track_width": true,
+    "hidden_netclasses": [],
     "hidden_nets": [],
     "high_contrast_mode": 0,
     "net_color_mode": 1,
     "opacity": {
+      "images": 0.6,
       "pads": 0.8500000238418579,
       "tracks": 1.0,
       "vias": 1.0,
@@ -48,15 +51,13 @@
       20,
       21,
       22,
-      23,
       24,
+      25,
+      26,
       27,
       28,
-      29,
-      30,
-      31,
-      32,
-      33,
+      34,
+      35,
       37,
       38
     ],
@@ -65,7 +66,7 @@
   },
   "meta": {
     "filename": "picovga.kicad_prl",
-    "version": 2
+    "version": 3
   },
   "project": {
     "files": []

designs/picovga/picovga.kicad_pro

@@ -1,5 +1,6 @@
 {
   "board": {
+    "3dviewports": [],
     "design_settings": {
       "defaults": {
         "board_outline_line_width": 0.09999999999999999,
@@ -51,25 +52,34 @@
       "diff_pair_dimensions": [],
       "drc_exclusions": [],
       "meta": {
-        "version": 1
+        "version": 2
       },
       "rule_severities": {
         "annular_width": "error",
         "clearance": "error",
+        "connection_width": "warning",
         "copper_edge_clearance": "error",
+        "copper_sliver": "warning",
         "courtyards_overlap": "error",
         "diff_pair_gap_out_of_range": "error",
         "diff_pair_uncoupled_length_too_long": "error",
+        "drill_out_of_range": "error",
         "drill_too_small": "error",
         "duplicate_footprints": "warning",
         "extra_footprint": "warning",
+        "footprint": "error",
+        "footprint_type_mismatch": "ignore",
         "hole_clearance": "error",
         "hole_near_hole": "error",
         "invalid_outline": "error",
+        "isolated_copper": "warning",
         "item_on_disabled_layer": "error",
         "items_not_allowed": "error",
         "length_out_of_range": "error",
+        "lib_footprint_issues": "warning",
+        "lib_footprint_mismatch": "warning",
         "malformed_courtyard": "error",
+        "microvia_drill_out_of_range": "error",
         "microvia_drill_too_small": "error",
         "missing_courtyard": "ignore",
         "missing_footprint": "warning",
@@ -78,9 +88,15 @@
         "padstack": "error",
         "pth_inside_courtyard": "ignore",
         "shorting_items": "error",
+        "silk_edge_clearance": "warning",
         "silk_over_copper": "error",
         "silk_overlap": "error",
         "skew_out_of_range": "error",
+        "solder_mask_bridge": "error",
+        "starved_thermal": "error",
+        "text_height": "warning",
+        "text_thickness": "warning",
+        "through_hole_pad_without_hole": "error",
         "too_many_vias": "error",
         "track_dangling": "warning",
         "track_width": "error",
@@ -96,27 +112,77 @@
         "allow_microvias": false,
         "max_error": 0.005,
         "min_clearance": 0.0,
+        "min_connection": 0.0,
         "min_copper_edge_clearance": 0.0,
         "min_hole_clearance": 0.0,
         "min_hole_to_hole": 0.25,
         "min_microvia_diameter": 0.19999999999999998,
         "min_microvia_drill": 0.09999999999999999,
+        "min_resolved_spokes": 2,
         "min_silk_clearance": 0.0,
+        "min_text_height": 0.7999999999999999,
+        "min_text_thickness": 0.08,
         "min_through_hole_diameter": 0.3,
         "min_track_width": 0.19999999999999998,
         "min_via_annular_width": 0.049999999999999996,
         "min_via_diameter": 0.39999999999999997,
         "solder_mask_clearance": 0.0,
         "solder_mask_min_width": 0.0,
+        "solder_mask_to_copper_clearance": 0.0,
         "solder_paste_clearance": 0.0,
-        "solder_paste_margin_ratio": 0.0
+        "solder_paste_margin_ratio": 0.0,
+        "use_height_for_length_calcs": true
       },
+      "teardrop_options": [
+        {
+          "td_onpadsmd": true,
+          "td_onroundshapesonly": false,
+          "td_ontrackend": false,
+          "td_onviapad": true
+        }
+      ],
+      "teardrop_parameters": [
+        {
+          "td_allow_use_two_tracks": true,
+          "td_curve_segcount": 0,
+          "td_height_ratio": 1.0,
+          "td_length_ratio": 0.5,
+          "td_maxheight": 2.0,
+          "td_maxlen": 1.0,
+          "td_on_pad_in_zone": false,
+          "td_target_name": "td_round_shape",
+          "td_width_to_size_filter_ratio": 0.9
+        },
+        {
+          "td_allow_use_two_tracks": true,
+          "td_curve_segcount": 0,
+          "td_height_ratio": 1.0,
+          "td_length_ratio": 0.5,
+          "td_maxheight": 2.0,
+          "td_maxlen": 1.0,
+          "td_on_pad_in_zone": false,
+          "td_target_name": "td_rect_shape",
+          "td_width_to_size_filter_ratio": 0.9
+        },
+        {
+          "td_allow_use_two_tracks": true,
+          "td_curve_segcount": 0,
+          "td_height_ratio": 1.0,
+          "td_length_ratio": 0.5,
+          "td_maxheight": 2.0,
+          "td_maxlen": 1.0,
+          "td_on_pad_in_zone": false,
+          "td_target_name": "td_track_end",
+          "td_width_to_size_filter_ratio": 0.9
+        }
+      ],
       "track_widths": [],
       "via_dimensions": [],
       "zones_allow_external_fillets": false,
       "zones_use_no_outline": true
     },
-    "layer_presets": []
+    "layer_presets": [],
+    "viewports": []
   },
   "boards": [],
   "cvpcb": {
@@ -134,6 +200,7 @@
         0,
         0,
         0,
+        0,
         1,
         0,
         0,
@@ -147,6 +214,7 @@
         0,
         1,
         0,
+        0,
         1,
         0,
         2,
@@ -160,6 +228,7 @@
         0,
         0,
         0,
+        0,
         1,
         0,
         1,
@@ -173,6 +242,7 @@
         0,
         0,
         0,
+        0,
         1,
         1,
         2,
@@ -186,6 +256,7 @@
         0,
         0,
         0,
+        0,
         1,
         0,
         0,
@@ -193,12 +264,27 @@
         0,
         2
       ],
+      [
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        0,
+        2
+      ],
       [
         1,
         1,
         1,
         1,
         1,
+        0,
         1,
         1,
         1,
@@ -212,6 +298,7 @@
         0,
         1,
         0,
+        0,
         1,
         0,
         0,
@@ -225,6 +312,7 @@
         1,
         2,
         0,
+        0,
         1,
         0,
         2,
@@ -238,6 +326,7 @@
         0,
         1,
         0,
+        0,
         1,
         0,
         2,
@@ -251,6 +340,7 @@
         1,
         1,
         0,
+        0,
         1,
         0,
         2,
@@ -269,21 +359,31 @@
         2,
         2,
         2,
+        2,
         2
       ]
     ],
     "rule_severities": {
       "bus_definition_conflict": "error",
+      "bus_entry_needed": "error",
       "bus_label_syntax": "error",
       "bus_to_bus_conflict": "error",
       "bus_to_net_conflict": "error",
+      "conflicting_netclasses": "error",
       "different_unit_footprint": "error",
       "different_unit_net": "error",
+      "duplicate_reference": "error",
       "duplicate_sheet_names": "error",
+      "endpoint_off_grid": "warning",
+      "extra_units": "error",
       "global_label_dangling": "warning",
       "hier_label_mismatch": "error",
       "label_dangling": "error",
       "lib_symbol_issues": "warning",
+      "missing_bidi_pin": "warning",
+      "missing_input_pin": "warning",
+      "missing_power_pin": "error",
+      "missing_unit": "warning",
       "multiple_net_names": "warning",
       "net_not_bus_member": "warning",
       "no_connect_connected": "warning",
@@ -293,6 +393,9 @@
       "pin_to_pin": "warning",
       "power_pin_not_driven": "error",
       "similar_labels": "warning",
+      "simulation_model_issue": "ignore",
+      "unannotated": "error",
+      "unit_value_mismatch": "error",
       "unresolved_variable": "error",
       "wire_dangling": "error"
     }
@@ -308,7 +411,7 @@
   "net_settings": {
     "classes": [
       {
-        "bus_width": 6.0,
+        "bus_width": 6,
         "clearance": 0.2,
         "diff_pair_gap": 0.25,
         "diff_pair_via_gap": 0.25,
@@ -322,13 +425,15 @@
         "track_width": 0.25,
         "via_diameter": 0.8,
         "via_drill": 0.4,
-        "wire_width": 6.0
+        "wire_width": 6
       }
     ],
     "meta": {
-      "version": 0
+      "version": 3
     },
-    "net_colors": null
+    "net_colors": null,
+    "netclass_assignments": null,
+    "netclass_patterns": []
   },
   "pcbnew": {
     "last_paths": {
@@ -342,31 +447,96 @@
     "page_layout_descr_file": ""
   },
   "schematic": {
+    "annotate_start_num": 0,
+    "bom_fmt_presets": [],
+    "bom_fmt_settings": {
+      "field_delimiter": ",",
+      "keep_line_breaks": false,
+      "keep_tabs": false,
+      "name": "CSV",
+      "ref_delimiter": ",",
+      "ref_range_delimiter": "",
+      "string_delimiter": "\""
+    },
+    "bom_presets": [],
+    "bom_settings": {
+      "exclude_dnp": false,
+      "fields_ordered": [
+        {
+          "group_by": false,
+          "label": "Reference",
+          "name": "Reference",
+          "show": true
+        },
+        {
+          "group_by": true,
+          "label": "Value",
+          "name": "Value",
+          "show": true
+        },
+        {
+          "group_by": false,
+          "label": "Datasheet",
+          "name": "Datasheet",
+          "show": true
+        },
+        {
+          "group_by": false,
+          "label": "Footprint",
+          "name": "Footprint",
+          "show": true
+        },
+        {
+          "group_by": false,
+          "label": "Qty",
+          "name": "Quantity",
+          "show": true
+        }
+      ],
+      "filter_string": "",
+      "group_symbols": true,
+      "name": "Grouped By Value",
+      "sort_asc": true,
+      "sort_field": "Reference"
+    },
     "drawing": {
+      "dashed_lines_dash_length_ratio": 12.0,
+      "dashed_lines_gap_length_ratio": 3.0,
       "default_bus_thickness": 12.0,
       "default_junction_size": 36.0,
       "default_line_thickness": 6.0,
       "default_text_size": 50.0,
       "default_wire_thickness": 6.0,
       "field_names": [],
+      "intersheets_ref_own_page": false,
       "intersheets_ref_prefix": "",
       "intersheets_ref_short": false,
       "intersheets_ref_show": false,
       "intersheets_ref_suffix": "",
       "junction_size_choice": 3,
+      "label_size_ratio": 0.3,
+      "operating_point_overlay_i_precision": 3,
+      "operating_point_overlay_i_range": "~A",
+      "operating_point_overlay_v_precision": 3,
+      "operating_point_overlay_v_range": "~V",
       "pin_symbol_size": 25.0,
       "text_offset_ratio": 0.3
     },
     "legacy_lib_dir": "",
     "legacy_lib_list": [],
     "meta": {
-      "version": 0
+      "version": 1
     },
     "net_format_name": "",
     "page_layout_descr_file": "",
     "plot_directory": "",
     "spice_adjust_passive_values": false,
+    "spice_current_sheet_as_root": false,
     "spice_external_command": "spice \"%I\"",
+    "spice_model_current_sheet_as_root": true,
+    "spice_save_all_currents": false,
+    "spice_save_all_dissipations": false,
+    "spice_save_all_voltages": false,
     "subpart_first_id": 65,
     "subpart_id_separator": 0
   },

main.c

@@ -1,40 +0,0 @@
-// Copyright Benjamin Kyd 2021 All Rights Reserved
-
-#include <stdio.h>
-
-#include "pico/stdlib.h"
-#include "hardware/clocks.h"
-#include "hardware/pio.h"
-#include "hardware/dma.h"
-#include "hardware/irq.h"
-
-#include "pico/stdlib.h"
-
-#include "vga.h"
-
-// PIN LAYOUT
-// PIN 0-3 RED DAC
-// PIN 4-7 GREEN DAC
-// PIN 8-11 BLUE DAC
-// PIN 12 HSYNC
-// PIN 13 VSYNC
-
-int main()
-{
-    stdio_init_all();
-    sleep_ms(1400);
-
-    gpio_init(PICO_DEFAULT_LED_PIN);
-    gpio_set_dir(PICO_DEFAULT_LED_PIN, GPIO_OUT);
-    gpio_put(PICO_DEFAULT_LED_PIN, 1);
-
-    printf("VGA Initalizing...\n");
-
-    const video_timing_t video_timing = vga_timing_800x600_60;
-    vga_init(&video_timing);
-
-    while(true) 
-    {
-        tight_loop_contents();
-    }
-}

makefile

@@ -0,0 +1,18 @@
+.ONESHELL:
+
+all: compile mount flash
+
+compile:
+	cd build && cmake .. -DCMAKE_EXPORT_COMPILE_COMMANDS=on && make
+
+mount: compile
+	sudo mount -L RPI-RP2 /mnt
+
+flash: mount
+	sudo cp build/pico_vga.uf2 /mnt
+	echo "Copied pico_vga.uf2 to pico"
+
+clean:
+	rm -rf build
+	mkdir build
+

pico_sdk_import.cmake

@@ -29,11 +29,22 @@ if (NOT PICO_SDK_PATH)
         if (PICO_SDK_FETCH_FROM_GIT_PATH)
             get_filename_component(FETCHCONTENT_BASE_DIR "${PICO_SDK_FETCH_FROM_GIT_PATH}" REALPATH BASE_DIR "${CMAKE_SOURCE_DIR}")
         endif ()
-        FetchContent_Declare(
-                pico_sdk
-                GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
-                GIT_TAG master
-        )
+        # GIT_SUBMODULES_RECURSE was added in 3.17
+        if (${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.17.0")
+            FetchContent_Declare(
+                    pico_sdk
+                    GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                    GIT_TAG master
+                    GIT_SUBMODULES_RECURSE FALSE
+            )
+        else ()
+            FetchContent_Declare(
+                    pico_sdk
+                    GIT_REPOSITORY https://github.com/raspberrypi/pico-sdk
+                    GIT_TAG master
+            )
+        endif ()
+
         if (NOT pico_sdk)
             message("Downloading Raspberry Pi Pico SDK")
             FetchContent_Populate(pico_sdk)

src/main.c

@@ -0,0 +1,32 @@
+// Copyright Benjamin Kyd 2023 All Rights Reserved
+//
+// GPIO 0-3: RED DAC, 4-7: GREEN DAC, 8-11: BLUE DAC
+// GPIO 12: HSYNC, GPIO 13: VSYNC
+
+#include "pico/stdlib.h"
+#include "vga.h"
+
+static void draw_test_pattern(void) {
+    for (int y = 0; y < VGA_FB_HEIGHT; y++) {
+        for (int x = 0; x < VGA_FB_WIDTH; x++) {
+            uint8_t r = (uint8_t)((x * 15) / VGA_FB_WIDTH);
+            uint8_t g = (uint8_t)((y * 15) / VGA_FB_HEIGHT);
+            uint8_t b = 8;
+
+            if (x % 10 == 0 || y % 10 == 0) {
+                r = g = b = 15;
+            }
+
+            vga_framebuffer[y][x] = vga_rgb(r, g, b);
+        }
+    }
+}
+
+int main(void) {
+    vga_init();
+    draw_test_pattern();
+
+    while (true) {
+        tight_loop_contents();
+    }
+}

src/vga.c

@@ -0,0 +1,118 @@
+#include <string.h>
+#include "pico/stdlib.h"
+#include "hardware/clocks.h"
+#include "hardware/pio.h"
+#include "hardware/dma.h"
+#include "hardware/irq.h"
+
+#include "vga.h"
+#include "vga.pio.h"
+
+#define H_ACTIVE        800
+#define H_FRONT_PORCH   40
+#define H_SYNC_PULSE    128
+#define H_BACK_PORCH    88
+#define H_TOTAL         1056
+
+#define V_ACTIVE        600
+#define V_FRONT_PORCH   1
+#define V_SYNC_PULSE    4
+#define V_BACK_PORCH    23
+#define V_TOTAL         628
+
+#define HSYNC_BIT   (1u << 12)
+#define VSYNC_BIT   (1u << 13)
+
+#define VGA_PIO         pio0
+#define VGA_SM          0
+#define VGA_DMA_CHAN    0
+
+static uint32_t scanline_buf[2][H_TOTAL];
+static volatile int      active_buf   = 0;
+static volatile uint32_t current_line = 0;
+
+vga_pixel_t vga_framebuffer[VGA_FB_HEIGHT][VGA_FB_WIDTH];
+
+static void build_scanline(uint32_t *buf, uint32_t line) {
+    const bool vsync = (line >= (uint32_t)(V_ACTIVE + V_FRONT_PORCH)) &&
+                       (line <  (uint32_t)(V_ACTIVE + V_FRONT_PORCH + V_SYNC_PULSE));
+    const uint32_t vsync_bit = vsync ? VSYNC_BIT : 0u;
+
+    uint32_t *ptr = buf;
+
+    if (line < V_ACTIVE) {
+        const uint32_t fy = line >> 2;
+        const vga_pixel_t *row = vga_framebuffer[fy < VGA_FB_HEIGHT ? fy : VGA_FB_HEIGHT - 1u];
+        for (int x = 0; x < H_ACTIVE; x++) {
+            *ptr++ = (uint32_t)row[x >> 2] | vsync_bit;
+        }
+    } else {
+        for (int x = 0; x < H_ACTIVE; x++) {
+            *ptr++ = vsync_bit;
+        }
+    }
+
+    for (int x = 0; x < H_FRONT_PORCH; x++) *ptr++ = vsync_bit;
+
+    const uint32_t hsync_word = HSYNC_BIT | vsync_bit;
+    for (int x = 0; x < H_SYNC_PULSE; x++) *ptr++ = hsync_word;
+
+    for (int x = 0; x < H_BACK_PORCH; x++) *ptr++ = vsync_bit;
+}
+
+static void dma_irq_handler(void) {
+    dma_hw->ints0 = 1u << VGA_DMA_CHAN;
+
+    current_line++;
+    if (current_line >= V_TOTAL) current_line = 0;
+
+    active_buf ^= 1;
+    dma_channel_set_read_addr(VGA_DMA_CHAN, scanline_buf[active_buf], false);
+    dma_channel_set_trans_count(VGA_DMA_CHAN, H_TOTAL, true);
+
+    const uint32_t next_line = (current_line + 1u) % V_TOTAL;
+    build_scanline(scanline_buf[active_buf ^ 1], next_line);
+}
+
+void vga_init(void) {
+    set_sys_clock_khz(120000, true);
+
+    const uint offset = pio_add_program(VGA_PIO, &vga_out_program);
+
+    pio_sm_config c = vga_out_program_get_default_config(offset);
+    sm_config_set_out_pins(&c, 0, 14);
+    sm_config_set_out_shift(&c, true, true, 14);
+    sm_config_set_clkdiv(&c, 3.0f);
+    sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
+
+    for (int i = 0; i < 14; i++) pio_gpio_init(VGA_PIO, i);
+    pio_sm_set_consecutive_pindirs(VGA_PIO, VGA_SM, 0, 14, true);
+    pio_sm_init(VGA_PIO, VGA_SM, offset, &c);
+
+    dma_channel_config dc = dma_channel_get_default_config(VGA_DMA_CHAN);
+    channel_config_set_transfer_data_size(&dc, DMA_SIZE_32);
+    channel_config_set_read_increment(&dc, true);
+    channel_config_set_write_increment(&dc, false);
+    channel_config_set_dreq(&dc, pio_get_dreq(VGA_PIO, VGA_SM, true));
+
+    dma_channel_configure(
+        VGA_DMA_CHAN, &dc,
+        &VGA_PIO->txf[VGA_SM],
+        scanline_buf[0],
+        H_TOTAL,
+        false
+    );
+
+    dma_channel_set_irq0_enabled(VGA_DMA_CHAN, true);
+    irq_set_exclusive_handler(DMA_IRQ_0, dma_irq_handler);
+    irq_set_enabled(DMA_IRQ_0, true);
+
+    build_scanline(scanline_buf[0], 0);
+    build_scanline(scanline_buf[1], 1);
+    active_buf   = 0;
+    current_line = 0;
+
+    pio_sm_set_enabled(VGA_PIO, VGA_SM, true);
+    dma_channel_set_read_addr(VGA_DMA_CHAN, scanline_buf[0], false);
+    dma_channel_set_trans_count(VGA_DMA_CHAN, H_TOTAL, true);
+}

src/vga.h

@@ -0,0 +1,23 @@
+#ifndef PICOVGA_VGA_H_
+#define PICOVGA_VGA_H_
+
+#include <stdint.h>
+
+#define VGA_FB_WIDTH  200
+#define VGA_FB_HEIGHT 150
+
+typedef uint16_t vga_pixel_t;
+
+static inline vga_pixel_t vga_rgb(uint8_t r, uint8_t g, uint8_t b) {
+    return (uint16_t)((r & 0xF) | ((g & 0xF) << 4) | ((b & 0xF) << 8));
+}
+
+static inline vga_pixel_t vga_rgb8(uint8_t r, uint8_t g, uint8_t b) {
+    return vga_rgb(r >> 4, g >> 4, b >> 4);
+}
+
+extern vga_pixel_t vga_framebuffer[VGA_FB_HEIGHT][VGA_FB_WIDTH];
+
+void vga_init(void);
+
+#endif

src/vga.pio

@@ -0,0 +1,19 @@
+;
+; VGA pixel output PIO program
+;
+; Outputs 14 bits per pixel clock cycle to GPIO 0-13:
+;   bits [3:0]   = RED   (GPIO 0-3)
+;   bits [7:4]   = GREEN (GPIO 4-7)
+;   bits [11:8]  = BLUE  (GPIO 8-11)
+;   bit  [12]    = HSYNC (GPIO 12) - positive polarity for 800x600@60Hz
+;   bit  [13]    = VSYNC (GPIO 13) - positive polarity for 800x600@60Hz
+;
+; Each 32-bit FIFO word = one pixel (14 bits used, 18 bits discarded via autopull).
+; PIO clock divider must be set so instruction rate = pixel clock (40 MHz).
+;
+
+.program vga_out
+
+.wrap_target
+    out pins, 14        ; output 14 bits to GPIO 0-13
+.wrap

vga.c

@@ -1,60 +0,0 @@
-// Copyright Benjamin Kyd 2021 All Rights Reserved
-
-#include <stdio.h>
-
-#include "pico/stdlib.h"
-#include "hardware/clocks.h"
-#include "hardware/pio.h"
-#include "hardware/dma.h"
-#include "hardware/irq.h"
-
-#include "vga.h"
-#include "video.pio.h"
-
-const video_timing_t vga_timing_800x600_60 =
-{
-        .clock_freq = 38400000,
-
-        .h_active = 800,
-        .v_active = 600,
-
-        .h_front_porch = 4 * 8,
-        .h_pulse = 10 * 8,
-        .h_total = 128 * 8,
-        .h_sync_polarity = 0,
-
-        .v_front_porch = 1,
-        .v_pulse = 3,
-        .v_total = 625,
-        .v_sync_polarity = 0,
-
-        .enable_clock = 0,
-        .clock_polarity = 0,
-
-        .enable_den = 0
-};
-
-#define PIN_START 8
-#define PIN_COUNT 2
-
-void vga_init(const video_timing_t* timing)
-{
-    // Calculate the PIO clock divider
-    uint sys_clock = frequency_count_khz(CLOCKS_FC0_SRC_VALUE_CLK_SYS);
-    float clock_div = ((float)sys_clock * 1000.f) / (float)timing->clock_freq;
-
-    printf("System clock frequency %i\n", sys_clock);
-    printf("Pixel clock frequency %i\n", timing->clock_freq);
-    printf("Clock divider %f\n", clock_div);
- 
-
-
-    // setup 2 buffers with DMA
-    // setup swap
-    
-    // use pin mask (5 pins for 1 bit colour, 12 for 4)
-
-
-
-}
-

vga.h

@@ -1,40 +0,0 @@
-#ifndef PICOVGA_VGA_H_
-#define PICOVGA_VGA_H_
-
-#include "pico/types.h"
-
-typedef struct video_timing {
-    uint32_t clock_freq;
-
-    uint16_t h_active;
-    uint16_t v_active;
-
-    uint16_t h_front_porch;
-    uint16_t h_pulse;
-    uint16_t h_total;
-    uint8_t h_sync_polarity;
-
-    uint16_t v_front_porch;
-    uint16_t v_pulse;
-    uint16_t v_total;
-    uint8_t v_sync_polarity;
-
-    uint8_t enable_clock;
-    uint8_t clock_polarity;
-
-    uint8_t enable_den;
-} video_timing_t;
-
-const video_timing_t vga_timing_800x600_60;
-
-// typedef struct video {
-//     uint16_t* 
-// } video_t;
-
-void vga_init(const video_timing_t* timing);
-
-void vga_start();
-
-void vga_swap_buffers();
-
-#endif

vga.txt

@@ -1,5 +0,0 @@
-WHITE - VSYNC - 
-BLACK - HSYNC - 
-RED   - VGA_R - 
-GREEN - VGA_G - 
-BLUE  - VGA_B - 

video.pio

@@ -1,28 +0,0 @@
-; Copyright Benjamin Kyd 2021 All Rights Reserved
-
-.program video
-
-; write 5 bits from the TX FIFO to the pin mask 
-
-.wrap_target
-    out pins 2
-.wrap
-
-% c-sdk {
-static inline void video_program_init(PIO pio, uint sm, uint offset, uint pin, float clk_div) {
-    pio_sm_config c = video_program_get_default_config(offset);
-
-    // Map the state machine's OUT pin group to one pin, namely the `pin`
-    // parameter to this function.
-    sm_config_set_out_pins(&c, pin, 1);
-    // Set this pin's GPIO function (connect PIO to the pad)
-    pio_gpio_init(pio, pin);
-    // Set the pin direction to output at the PIO
-    pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, true);
-
-    // Load our configuration, and jump to the start of the program
-    pio_sm_init(pio, sm, offset, &c);
-    // Set the state machine running
-    pio_sm_set_enabled(pio, sm, true);
-}
-%}