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There are only a limited number of devices that can take the picoDVI and Framebuffer resolution of 640x480 at 72 Hz. After a detailed discussion with Claude Sonnet 4, it believes it has the parameters to add that mode to the existing code base without extensive changes. A sample Framebuffer setup:
import board
import picodvi
# 60Hz for capture card compatibility
fb = picodvi.Framebuffer(640, 480,
clk_dp=board.CKP, clk_dn=board.CKN,
red_dp=board.D0P, red_dn=board.D0N,
green_dp=board.D1P, green_dn=board.D1N,
blue_dp=board.D2P, blue_dn=board.D2N,
color_depth=8, refresh_rate=60)
# Or using constants
fb = picodvi.Framebuffer(640, 480, ...,
refresh_rate=picodvi.REFRESH_60HZ)
Here is the code:
/*
* Complete implementation for adding 640x480@60Hz support to CircuitPython picodvi
*
* Files to be modified:
* 1. shared-bindings/picodvi/Framebuffer.h
* 2. shared-bindings/picodvi/Framebuffer.c
* 3. shared-bindings/picodvi/__init__.c
* 4. ports/raspberrypi/common-hal/picodvi/Framebuffer_RP2350.c
* 5. ports/raspberrypi/bindings/picodvi/Framebuffer.h
*/
// ============================================================================
// 1. shared-bindings/picodvi/Framebuffer.h
// ============================================================================
#pragma once
#include "common-hal/picodvi/Framebuffer.h"
#include "shared-module/displayio/Group.h"
extern const mp_obj_type_t picodvi_framebuffer_type;
// Add refresh rate constants
typedef enum {
PICODVI_REFRESH_60HZ = 60,
PICODVI_REFRESH_72HZ = 72
} picodvi_refresh_rate_t;
void common_hal_picodvi_framebuffer_construct(picodvi_framebuffer_obj_t *self,
mp_uint_t width, mp_uint_t height,
const mcu_pin_obj_t *clk_dp, const mcu_pin_obj_t *clk_dn,
const mcu_pin_obj_t *red_dp, const mcu_pin_obj_t *red_dn,
const mcu_pin_obj_t *green_dp, const mcu_pin_obj_t *green_dn,
const mcu_pin_obj_t *blue_dp, const mcu_pin_obj_t *blue_dn,
mp_uint_t color_depth, mp_uint_t refresh_rate);
bool common_hal_picodvi_framebuffer_preflight(
mp_uint_t width, mp_uint_t height,
mp_uint_t color_depth, mp_uint_t refresh_rate);
void common_hal_picodvi_framebuffer_deinit(picodvi_framebuffer_obj_t *self);
void common_hal_picodvi_framebuffer_refresh(picodvi_framebuffer_obj_t *self);
int common_hal_picodvi_framebuffer_get_width(picodvi_framebuffer_obj_t *self);
int common_hal_picodvi_framebuffer_get_height(picodvi_framebuffer_obj_t *self);
// ============================================================================
// 2. shared-bindings/picodvi/Framebuffer.c
// ============================================================================
#include "shared-bindings/picodvi/Framebuffer.h"
#include "shared-bindings/microcontroller/Pin.h"
#include "shared-bindings/util.h"
#include "shared-module/framebufferio/__init__.h"
#include "py/runtime.h"
#include "py/objproperty.h"
//| class Framebuffer:
//| """A picodvi framebuffer for DVI output."""
//|
//| def __init__(
//| self,
//| width: int,
//| height: int,
//| *,
//| clk_dp: microcontroller.Pin,
//| clk_dn: microcontroller.Pin,
//| red_dp: microcontroller.Pin,
//| red_dn: microcontroller.Pin,
//| green_dp: microcontroller.Pin,
//| green_dn: microcontroller.Pin,
//| blue_dp: microcontroller.Pin,
//| blue_dn: microcontroller.Pin,
//| color_depth: int = 8,
//| refresh_rate: int = 72,
//| ) -> None:
//| """Create a Framebuffer object with the given parameters.
//|
//| :param int width: the width of the framebuffer
//| :param int height: the height of the framebuffer
//| :param microcontroller.Pin clk_dp: the positive clock pin
//| :param microcontroller.Pin clk_dn: the negative clock pin
//| :param microcontroller.Pin red_dp: the positive red pin
//| :param microcontroller.Pin red_dn: the negative red pin
//| :param microcontroller.Pin green_dp: the positive green pin
//| :param microcontroller.Pin green_dn: the negative green pin
//| :param microcontroller.Pin blue_dp: the positive blue pin
//| :param microcontroller.Pin blue_dn: the negative blue pin
//| :param int color_depth: the color depth in bits per pixel
//| :param int refresh_rate: the refresh rate in Hz (60 or 72)
//| """
//| ...
STATIC mp_obj_t picodvi_framebuffer_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
enum { ARG_width, ARG_height, ARG_clk_dp, ARG_clk_dn, ARG_red_dp, ARG_red_dn, ARG_green_dp, ARG_green_dn, ARG_blue_dp, ARG_blue_dn, ARG_color_depth, ARG_refresh_rate };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_width, MP_ARG_REQUIRED | MP_ARG_INT },
{ MP_QSTR_height, MP_ARG_REQUIRED | MP_ARG_INT },
{ MP_QSTR_clk_dp, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_clk_dn, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_red_dp, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_red_dn, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_green_dp, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_green_dn, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_blue_dp, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_blue_dn, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_color_depth, MP_ARG_INT, {.u_int = 8} },
{ MP_QSTR_refresh_rate, MP_ARG_INT, {.u_int = 72} },
};
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
mp_uint_t width = args[ARG_width].u_int;
mp_uint_t height = args[ARG_height].u_int;
mp_uint_t color_depth = args[ARG_color_depth].u_int;
mp_uint_t refresh_rate = args[ARG_refresh_rate].u_int;
// Validate refresh rate
if (refresh_rate != 60 && refresh_rate != 72) {
mp_raise_ValueError(MP_ERROR_TEXT("refresh_rate must be 60 or 72"));
}
const mcu_pin_obj_t *clk_dp = validate_obj_is_free_pin(args[ARG_clk_dp].u_obj, MP_QSTR_clk_dp);
const mcu_pin_obj_t *clk_dn = validate_obj_is_free_pin(args[ARG_clk_dn].u_obj, MP_QSTR_clk_dn);
const mcu_pin_obj_t *red_dp = validate_obj_is_free_pin(args[ARG_red_dp].u_obj, MP_QSTR_red_dp);
const mcu_pin_obj_t *red_dn = validate_obj_is_free_pin(args[ARG_red_dn].u_obj, MP_QSTR_red_dn);
const mcu_pin_obj_t *green_dp = validate_obj_is_free_pin(args[ARG_green_dp].u_obj, MP_QSTR_green_dp);
const mcu_pin_obj_t *green_dn = validate_obj_is_free_pin(args[ARG_green_dn].u_obj, MP_QSTR_green_dn);
const mcu_pin_obj_t *blue_dp = validate_obj_is_free_pin(args[ARG_blue_dp].u_obj, MP_QSTR_blue_dp);
const mcu_pin_obj_t *blue_dn = validate_obj_is_free_pin(args[ARG_blue_dn].u_obj, MP_QSTR_blue_dn);
picodvi_framebuffer_obj_t *self = m_new_obj(picodvi_framebuffer_obj_t);
self->base.type = &picodvi_framebuffer_type;
common_hal_picodvi_framebuffer_construct(self, width, height,
clk_dp, clk_dn, red_dp, red_dn, green_dp, green_dn, blue_dp, blue_dn,
color_depth, refresh_rate);
return MP_OBJ_FROM_PTR(self);
}
//| def deinit(self) -> None:
//| """Free the resources associated with this picodvi object."""
//| ...
STATIC mp_obj_t picodvi_framebuffer_deinit(mp_obj_t self_in) {
picodvi_framebuffer_obj_t *self = (picodvi_framebuffer_obj_t *)self_in;
common_hal_picodvi_framebuffer_deinit(self);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(picodvi_framebuffer_deinit_obj, picodvi_framebuffer_deinit);
//| width: int
//| """The width of the framebuffer in pixels."""
STATIC mp_obj_t picodvi_framebuffer_obj_get_width(mp_obj_t self_in) {
picodvi_framebuffer_obj_t *self = (picodvi_framebuffer_obj_t *)self_in;
return MP_OBJ_NEW_SMALL_INT(common_hal_picodvi_framebuffer_get_width(self));
}
MP_DEFINE_CONST_FUN_OBJ_1(picodvi_framebuffer_get_width_obj, picodvi_framebuffer_obj_get_width);
MP_PROPERTY_GETTER(picodvi_framebuffer_width_obj,
(mp_obj_t)&picodvi_framebuffer_get_width_obj);
//| height: int
//| """The height of the framebuffer in pixels."""
STATIC mp_obj_t picodvi_framebuffer_obj_get_height(mp_obj_t self_in) {
picodvi_framebuffer_obj_t *self = (picodvi_framebuffer_obj_t *)self_in;
return MP_OBJ_NEW_SMALL_INT(common_hal_picodvi_framebuffer_get_height(self));
}
MP_DEFINE_CONST_FUN_OBJ_1(picodvi_framebuffer_get_height_obj, picodvi_framebuffer_obj_get_height);
MP_PROPERTY_GETTER(picodvi_framebuffer_height_obj,
(mp_obj_t)&picodvi_framebuffer_get_height_obj);
STATIC const mp_rom_map_elem_t picodvi_framebuffer_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&picodvi_framebuffer_deinit_obj) },
{ MP_ROM_QSTR(MP_QSTR_width), MP_ROM_PTR(&picodvi_framebuffer_width_obj) },
{ MP_ROM_QSTR(MP_QSTR_height), MP_ROM_PTR(&picodvi_framebuffer_height_obj) },
};
STATIC MP_DEFINE_CONST_DICT(picodvi_framebuffer_locals_dict, picodvi_framebuffer_locals_dict_table);
const mp_obj_type_t picodvi_framebuffer_type = {
{ &mp_type_type },
.name = MP_QSTR_Framebuffer,
.make_new = picodvi_framebuffer_make_new,
.locals_dict = (mp_obj_dict_t *)&picodvi_framebuffer_locals_dict,
};
// ============================================================================
// 3. shared-bindings/picodvi/__init__.c
// ============================================================================
#include "py/obj.h"
#include "py/runtime.h"
#include "shared-bindings/picodvi/Framebuffer.h"
//| """DVI video output using PicoDVI
//|
//| .. note:: This module requires an RP2350 and specific pins.
//|
//| """
STATIC const mp_rom_map_elem_t picodvi_module_globals_table[] = {
{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_picodvi) },
{ MP_ROM_QSTR(MP_QSTR_Framebuffer), MP_ROM_PTR(&picodvi_framebuffer_type) },
// Refresh rate constants
{ MP_ROM_QSTR(MP_QSTR_REFRESH_60HZ), MP_ROM_INT(60) },
{ MP_ROM_QSTR(MP_QSTR_REFRESH_72HZ), MP_ROM_INT(72) },
};
STATIC MP_DEFINE_CONST_DICT(picodvi_module_globals, picodvi_module_globals_table);
const mp_obj_module_t picodvi_module = {
.base = { &mp_type_module },
.globals = (mp_obj_dict_t *)&picodvi_module_globals,
};
MP_REGISTER_MODULE(MP_QSTR_picodvi, picodvi_module);
// ============================================================================
// 4. ports/raspberrypi/bindings/picodvi/Framebuffer.h
// ============================================================================
#pragma once
#include "common-hal/picodvi/Framebuffer.h"
extern const mp_obj_type_t picodvi_framebuffer_type;
// ============================================================================
// 5. ports/raspberrypi/common-hal/picodvi/Framebuffer_RP2350.c (Enhanced)
// ============================================================================
/*
* This file is part of the CircuitPython project: https://circuitpython.org
*
* SPDX-FileCopyrightText: Copyright (c) 2024 Scott Shawcroft for Adafruit Industries
*
* SPDX-License-Identifier: MIT
*
* Enhanced version with 60Hz/72Hz refresh rate support
*/
#include "bindings/picodvi/Framebuffer.h"
#include "py/gc.h"
#include "py/runtime.h"
#include "shared-bindings/time/__init__.h"
#include "supervisor/port.h"
#include "pico/stdlib.h"
// This is from: https://github.com/raspberrypi/pico-examples-rp2350/blob/a1/hstx/dvi_out_hstx_encoder/dvi_out_hstx_encoder.c
#include "hardware/dma.h"
#include "hardware/structs/bus_ctrl.h"
#include "hardware/structs/hstx_ctrl.h"
#include "hardware/structs/hstx_fifo.h"
#include "hardware/clocks.h"
// ----------------------------------------------------------------------------
// DVI constants
#define TMDS_CTRL_00 0x354u
#define TMDS_CTRL_01 0x0abu
#define TMDS_CTRL_10 0x154u
#define TMDS_CTRL_11 0x2abu
#define SYNC_V0_H0 (TMDS_CTRL_00 | (TMDS_CTRL_00 << 10) | (TMDS_CTRL_00 << 20))
#define SYNC_V0_H1 (TMDS_CTRL_01 | (TMDS_CTRL_00 << 10) | (TMDS_CTRL_00 << 20))
#define SYNC_V1_H0 (TMDS_CTRL_10 | (TMDS_CTRL_00 << 10) | (TMDS_CTRL_00 << 20))
#define SYNC_V1_H1 (TMDS_CTRL_11 | (TMDS_CTRL_00 << 10) | (TMDS_CTRL_00 << 20))
// Timing constants for different refresh rates
// 640x480 @ 72Hz (VGA standard)
#define TIMING_72HZ_H_ACTIVE 640
#define TIMING_72HZ_H_FRONT 24
#define TIMING_72HZ_H_SYNC 40
#define TIMING_72HZ_H_BACK 128
#define TIMING_72HZ_V_ACTIVE 480
#define TIMING_72HZ_V_FRONT 9
#define TIMING_72HZ_V_SYNC 3
#define TIMING_72HZ_V_BACK 28
#define TIMING_72HZ_PIX_CLOCK 31500000 // 31.5 MHz
#define TIMING_72HZ_HSTX_CLOCK 125000000 // 125 MHz
// 640x480 @ 60Hz (VGA standard)
#define TIMING_60HZ_H_ACTIVE 640
#define TIMING_60HZ_H_FRONT 16
#define TIMING_60HZ_H_SYNC 96
#define TIMING_60HZ_H_BACK 48
#define TIMING_60HZ_V_ACTIVE 480
#define TIMING_60HZ_V_FRONT 10
#define TIMING_60HZ_V_SYNC 2
#define TIMING_60HZ_V_BACK 33
#define TIMING_60HZ_PIX_CLOCK 25175000 // 25.175 MHz
#define TIMING_60HZ_HSTX_CLOCK 104166667 // ~104.17 MHz (close to 25.175*4.1458)
typedef struct {
uint16_t h_active, h_front, h_sync, h_back;
uint16_t v_active, v_front, v_sync, v_back;
uint32_t pixel_clock;
uint32_t hstx_clock;
} dvi_timing_t;
static const dvi_timing_t timing_60hz = {
.h_active = TIMING_60HZ_H_ACTIVE,
.h_front = TIMING_60HZ_H_FRONT,
.h_sync = TIMING_60HZ_H_SYNC,
.h_back = TIMING_60HZ_H_BACK,
.v_active = TIMING_60HZ_V_ACTIVE,
.v_front = TIMING_60HZ_V_FRONT,
.v_sync = TIMING_60HZ_V_SYNC,
.v_back = TIMING_60HZ_V_BACK,
.pixel_clock = TIMING_60HZ_PIX_CLOCK,
.hstx_clock = TIMING_60HZ_HSTX_CLOCK
};
static const dvi_timing_t timing_72hz = {
.h_active = TIMING_72HZ_H_ACTIVE,
.h_front = TIMING_72HZ_H_FRONT,
.h_sync = TIMING_72HZ_H_SYNC,
.h_back = TIMING_72HZ_H_BACK,
.v_active = TIMING_72HZ_V_ACTIVE,
.v_front = TIMING_72HZ_V_FRONT,
.v_sync = TIMING_72HZ_V_SYNC,
.v_back = TIMING_72HZ_V_BACK,
.pixel_clock = TIMING_72HZ_PIX_CLOCK,
.hstx_clock = TIMING_72HZ_HSTX_CLOCK
};
// ... [rest of existing constants and variables] ...
static picodvi_framebuffer_obj_t *active_picodvi = NULL;
static uint32_t *dma_commands;
static size_t dma_commands_len;
// Add timing parameter to get correct timing
static const dvi_timing_t* get_timing_for_refresh_rate(mp_uint_t refresh_rate) {
switch (refresh_rate) {
case 60:
return &timing_60hz;
case 72:
return &timing_72hz;
default:
return &timing_72hz; // Default fallback
}
}
// Enhanced preflight check with refresh rate validation
bool common_hal_picodvi_framebuffer_preflight(
mp_uint_t width, mp_uint_t height,
mp_uint_t color_depth, mp_uint_t refresh_rate) {
// Validate refresh rate first
if (refresh_rate != 60 && refresh_rate != 72) {
return false;
}
// These modes don't duplicate pixels so we can do sub-byte colors. They
// take too much ram for more than 8bit color though.
bool full_resolution = color_depth == 1 || color_depth == 2 || color_depth == 4 || color_depth == 8;
// These modes rely on the memory transfer to duplicate values across bytes.
bool doubled = color_depth == 8 || color_depth == 16 || color_depth == 32;
// for each supported resolution, check the color depth is supported
if (width == 640 && height == 480) {
return full_resolution;
}
if (width == 320 && height == 240) {
return doubled;
}
if (width == 720 && height == 400) {
return full_resolution;
}
if (width == 360 && height == 200) {
return doubled;
}
if (width == 180 && height == 100) {
return doubled;
}
return false;
}
// Enhanced constructor with refresh rate support
void common_hal_picodvi_framebuffer_construct(picodvi_framebuffer_obj_t *self,
mp_uint_t width, mp_uint_t height,
const mcu_pin_obj_t *clk_dp, const mcu_pin_obj_t *clk_dn,
const mcu_pin_obj_t *red_dp, const mcu_pin_obj_t *red_dn,
const mcu_pin_obj_t *green_dp, const mcu_pin_obj_t *green_dn,
const mcu_pin_obj_t *blue_dp, const mcu_pin_obj_t *blue_dn,
mp_uint_t color_depth, mp_uint_t refresh_rate) {
if (active_picodvi != NULL) {
mp_raise_msg_varg(&mp_type_RuntimeError, MP_ERROR_TEXT("%q in use"), MP_QSTR_picodvi);
}
if (!common_hal_picodvi_framebuffer_preflight(width, height, color_depth, refresh_rate)) {
mp_raise_ValueError_varg(MP_ERROR_TEXT("Invalid %q, %q, or refresh rate"), MP_QSTR_width, MP_QSTR_height);
}
// Get timing parameters for the requested refresh rate
const dvi_timing_t* timing = get_timing_for_refresh_rate(refresh_rate);
// Validate pins (existing validation code)
if (clk_dp->number != 14 || clk_dn->number != 15 ||
red_dp->number != 12 || red_dn->number != 13 ||
green_dp->number != 18 || green_dn->number != 19 ||
blue_dp->number != 16 || blue_dn->number != 17) {
mp_raise_ValueError(MP_ERROR_TEXT("Invalid HSTX pins"));
}
// Set up HSTX with timing-specific clock
clock_configure(clk_hstx,
0, // No glitchless mux
CLOCKS_CLK_HSTX_CTRL_AUXSRC_VALUE_CLKSRC_PLL_SYS,
timing->hstx_clock * 2, // PLL runs at 2x HSTX clock
timing->hstx_clock);
// Calculate timing parameters
uint32_t h_total = timing->h_active + timing->h_front + timing->h_sync + timing->h_back;
uint32_t v_total = timing->v_active + timing->v_front + timing->v_sync + timing->v_back;
// Store timing info in self
self->width = width;
self->height = height;
self->color_depth = color_depth;
self->refresh_rate = refresh_rate;
// Generate DMA commands based on timing
self->h_active = timing->h_active;
self->h_front = timing->h_front;
self->h_sync = timing->h_sync;
self->h_back = timing->h_back;
self->v_active = timing->v_active;
self->v_front = timing->v_front;
self->v_sync = timing->v_sync;
self->v_back = timing->v_back;
// Configure HSTX with appropriate clock divisor for the refresh rate
uint32_t clkdiv, n_shifts, shift_amount;
if (refresh_rate == 60) {
// 60Hz timing: adjust for slower pixel clock
clkdiv = 6; // Slower clock division
n_shifts = 6;
shift_amount = 2;
} else {
// 72Hz timing: original values
clkdiv = 5;
n_shifts = 5;
shift_amount = 2;
}
// Configure HSTX with timing-specific parameters
hstx_ctrl_hw->csr = 0;
hstx_ctrl_hw->csr =
HSTX_CTRL_CSR_EXPAND_EN_BITS |
clkdiv << HSTX_CTRL_CSR_CLKDIV_LSB |
n_shifts << HSTX_CTRL_CSR_N_SHIFTS_LSB |
shift_amount << HSTX_CTRL_CSR_SHIFT_LSB |
HSTX_CTRL_CSR_EN_BITS;
// ... [rest of existing initialization code] ...
// [The existing framebuffer setup, DMA configuration, etc. remains the same]
active_picodvi = self;
}
void common_hal_picodvi_framebuffer_deinit(picodvi_framebuffer_obj_t *self) {
if (active_picodvi == self) {
// Stop HSTX
hstx_ctrl_hw->csr = 0;
// Free DMA channels
if (self->dma_pixel_channel >= 0) {
dma_channel_unclaim(self->dma_pixel_channel);
self->dma_pixel_channel = -1;
}
if (self->dma_command_channel >= 0) {
dma_channel_unclaim(self->dma_command_channel);
self->dma_command_channel = -1;
}
// Free framebuffer memory
if (self->framebuffer) {
m_free(self->framebuffer);
self->framebuffer = NULL;
}
active_picodvi = NULL;
}
}
void common_hal_picodvi_framebuffer_refresh(picodvi_framebuffer_obj_t *self) {
// Force a refresh of the display
if (active_picodvi == self) {
// Trigger DMA restart
dma_channel_hw_t *ch = &dma_hw->ch[self->dma_command_channel];
ch->al3_read_addr_trig = (uintptr_t)self->dma_commands;
}
}
int common_hal_picodvi_framebuffer_get_width(picodvi_framebuffer_obj_t *self) {
return self->width;
}
int common_hal_picodvi_framebuffer_get_height(picodvi_framebuffer_obj_t *self) {
return self->height;
}
// ============================================================================
// 6. ports/raspberrypi/common-hal/picodvi/Framebuffer.h (Enhanced)
// ============================================================================
#pragma once
#include "py/obj.h"
typedef struct {
mp_obj_base_t base;
// Display parameters
uint16_t width;
uint16_t height;
uint8_t color_depth;
uint8_t refresh_rate; // New field for refresh rate
// Timing parameters (new fields)
uint16_t h_active, h_front, h_sync, h_back;
uint16_t v_active, v_front, v_sync, v_back;
// Hardware resources
int dma_pixel_channel;
int dma_command_channel;
// Framebuffer
void *framebuffer;
size_t framebuffer_len;
// DMA commands
uint32_t *dma_commands;
size_t dma_commands_len;
} picodvi_framebuffer_obj_t;