ZYNQ条记（十九）：VDMA VGA 输出分辨率可调

农民 · 2025-5-11 02:45:57

版本：Vivado2020.2（Vitis）
  使命：以 VDAM IP 为焦点实现 VGA 彩条图像显示，同时支持输出分辨率可调。
  （PS 端写入彩条数据到 DDR 通过 VDMA 读取出来输出给 VGA 进行显示）
  目录
一、介绍
二、硬件设计
（1）整体系统框架
（2）VTC 配置
（3）Clock 时钟配置
（4）RGB888_to_444
（5）连线
三、软件设计
（1）clk_wiz
（2）display_ctrl
（3）main.c
四、效果

一、介绍

        本例基于上次例程进行优化，实现 VGA 彩条图像显示的同时，支持输出分辨率可调，以满足差别视频分辨率的需求。
参考了正点原子的例程，但有所差别，他是通过 AXI GPIO 读取 LCD装备型号 ID 判断并配置分辨率。而我使用 VGA 进行显示且大多数 VGA 显示器都支持多种分辨率输入，对于差别型号 VGA 显示器各有差别，以是就直接通过PS端主动调节输出分辨率即可。本次只设计三种 VGA 分辨率可调：640*480@60Hz、800x600@60Hz、1280*720@60Hz。

二、硬件设计

（1）整体系统框架

        框架和 “条记十八”内里一致，区别在于时钟IP配置为可动态调节，PS端通过 GP 接口可对其输出时钟进行配置，别的还将 RGB888_to_444 模块进行优化并封装为带 vid_io_rtl 范例接口输入的 IP核，使BD设计视图更加简洁清晰。
        基本原理、相关 IP 介绍、系统框架搭建参考：ZYNQ条记（十八）：VDMA VGA彩条显示

（2）VTC 配置

在之前配置的基础上添加 AXI-Lite 接口，如许 PS 端可以通过 GP 接口对其进行配置

（3）Clock 时钟配置

差别分辨率像素时钟差别，以是必要对应输出差别频率的时钟，Clock IP 启用动态配置功能，可以看到 IP 增长了一组 AXI-Lite 接口。如许 PS 端可以通过 GP 接口对其输出时钟频率进行重新配置。

（4）RGB888_to_444

之前的 RGB888_to_444 是作为模块添加到 bd设计中，将Video Out 输出的 RGB888 数据进行截位与拼接，输出 RGB444 格式数据。为了让 bd 设计更加简洁规范，把它封装为有关带 vid_io_rtl 范例接口输入的 IP 核，以毗连 Video Out IP 的视频信号接口。

`timescale 1ns / 1ps
module RGB888_to_444(
input wire vid_hsync, // 输入行同步信号
input wire vid_vsync, // 输入场同步信号
input wire [23:0] RGB888, // 24位RGB888输入 (R[23:16], G[15:8], B[7:0])
output wire hsync, // 输出行同步信号
output wire vsync, // 输出场同步信号
output wire [11:0] RGB444 // 12位RGB444输出 (R[11:8], G[7:4], B[3:0])
);
assign vsync = vid_vsync;
assign hsync = vid_hsync;
assign RGB444 = {RGB888[23:20], RGB888[15:12], RGB888[7:4]}; // 截取RGB888各通道的高4位，组合成RGB444
endmodule

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IP 封装以及接口定义参考：ZYNQ条记（十七）：IP核封装与接口定义

（5）连线

完成关键信号连线，连线环境如图所示：

再运行主动毗连，最后整体 bd 设计部门如图所示：设计检查、Generate Output Products、 Create HDL Wrapper、管脚约束、Gnerate Bitstream、Export Hardware（包含比特流文件）、启动Vitis

三、软件设计

（1）clk_wiz

"xclk_wiz.h" 是Vitis提供的关于时钟IP核相关的库函数头文，"clk_wiz.h" 是自己编写的用于定义时钟相关寄存器的头文件。
clk_wiz.h :

#ifndef CLK_WIZ_H_
#define CLK_WIZ_H_
#include "xil_types.h"
#define CLK_SR_OFFSET 0x04 //Status Register
#define CLK_CFG0_OFFSET 0x200 //Clock Configuration Register 0
#define CLK_CFG2_OFFSET 0x208 //Clock Configuration Register 2
#define CLK_CFG23_OFFSET 0x25C //Clock Configuration Register 23
void clk_wiz_cfg(u32 clk_device_id,double freq);
#endif /* CLK_WIZ_H_ */

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clk_wiz.c :

#include "xclk_wiz.h"
#include "clk_wiz.h"
#include "xparameters.h"
#define CLK_WIZ_IN_FREQ 100 //时钟IP核输入100Mhz
XClk_Wiz clk_wiz_inst; //时钟IP核驱动实例
//时钟IP核动态重配置
//参数1:时钟IP核的器件ID
//参数2:时钟IP核输出的时钟单位：MHz
void clk_wiz_cfg(u32 clk_device_id,double freq)
{
double div_factor = 0;
u32 div_factor_int = 0,dviv_factor_frac=0;
u32 clk_divide = 0;
u32 status = 0;
//初始化XCLK_Wiz
XClk_Wiz_Config *clk_cfg_ptr;
clk_cfg_ptr = XClk_Wiz_LookupConfig(clk_device_id);
XClk_Wiz_CfgInitialize(&clk_wiz_inst,clk_cfg_ptr,clk_cfg_ptr->BaseAddr);
if(freq <= 0)
return;
//配置时钟倍频/分频系数
XClk_Wiz_WriteReg(clk_cfg_ptr->BaseAddr,CLK_CFG0_OFFSET,0x00000a01); //10倍频，1分频
//计算分频系数
div_factor = CLK_WIZ_IN_FREQ * 10 / freq;
div_factor_int = (u32)div_factor;
dviv_factor_frac = (u32)((div_factor - div_factor_int) * 1000);
clk_divide = div_factor_int | (dviv_factor_frac<<8);
//配置分频系数
XClk_Wiz_WriteReg(clk_cfg_ptr->BaseAddr,CLK_CFG2_OFFSET,clk_divide);
//加载重配置的参数
XClk_Wiz_WriteReg(clk_cfg_ptr->BaseAddr,CLK_CFG23_OFFSET,0x00000003);
//获取时钟IP核的状态，判断是否重配置完成
while(1){
status = XClk_Wiz_ReadReg(clk_cfg_ptr->BaseAddr,CLK_SR_OFFSET);
if(status&0x00000001) //Bit0 Locked信号
return ;
}
}

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（2）display_ctrl

这一部门使用的正点原子的代码，display_ctrl.c 和.h 是用于实现 VTC 配置的，不外做了一些微调（本例没用到GPIO）。同时还有一个 lcd_modes.h 包含差别分辨率格式的时序配置参数，同样适用于 VGA 显示器。代码如下：
display_ctrl.c

/************************************************************************/
/* */
/* display_ctrl.c -- Digilent Display Controller Driver */
/* */
/************************************************************************/
/* Author: Sam Bobrowicz */
/* Copyright 2014, Digilent Inc. */
/************************************************************************/
/* Module Description: */
/* */
/* This module provides an easy to use API for controlling a */
/* Display attached to a Digilent system board via VGA or HDMI. */
/* run-time resolution setting and seamless framebuffer-swapping */
/* for tear-free animation. */
/* */
/* To use this driver, you must have a Xilinx Video Timing */
/* Controller core (vtc), Xilinx axi_vdma core, a Digilent */
/* axi_dynclk core, a Xilinx AXI Stream to Video core, and either */
/* a Digilent RGB2VGA or RGB2DVI core all present in your design. */
/* See the Video in or Display out reference projects for your */
/* system board to see how they need to be connected. Digilent */
/* reference projects and IP cores can be found at */
/* www.github.com/Digilent. */
/* */
/* The following steps should be followed to use this driver: */
/* 1) Create a DisplayCtrl object and pass a pointer to it to */
/* DisplayInitialize. */
/* 2) Call DisplaySetMode to set the desired mode */
/* 3) Call DisplayStart to begin outputting data to the display */
/* 4) To create a seamless animation, draw the next image to a */
/* framebuffer currently not being displayed. Then call */
/* DisplayChangeFrame to begin displaying that frame. */
/* Repeat as needed, only ever modifying inactive frames. */
/* 5) To change the resolution, call DisplaySetMode, followed by */
/* DisplayStart again. */
/* */
/* */
/************************************************************************/
/* Revision History: */
/* */
/* 2/20/2014(SamB): Created */
/* 11/25/2015(SamB): Changed from axi_dispctrl to Xilinx cores */
/* Separated Clock functions into dynclk library */
/* */
/************************************************************************/
/*
* TODO: It would be nice to remove the need for users above this to access
* members of the DisplayCtrl struct manually. This can be done by
* implementing get/set functions for things like video mode, state,
* etc.
*/
/* ------------------------------------------------------------ */
/* Include File Definitions */
/* ------------------------------------------------------------ */
/*
* Uncomment for Debugging messages over UART
*/
//#define DEBUG
#include "display_ctrl.h"
#include "xdebug.h"
#include "xil_io.h"
/* ------------------------------------------------------------ */
/* Procedure Definitions */
/* ------------------------------------------------------------ */
/*** DisplayStop(DisplayCtrl *dispPtr)
**
** Parameters:
** dispPtr - Pointer to the initialized DisplayCtrl struct
**
** Return Value: int
** XST_SUCCESS if successful.
** XST_DMA_ERROR if an error was detected on the DMA channel. The
** Display is still successfully stopped, and the error is
** cleared so that subsequent DisplayStart calls will be
** successful. This typically indicates insufficient bandwidth
** on the AXI Memory-Map Interconnect (VDMA<->DDR)
**
** Description:
** Halts output to the display
**
*/
int DisplayStop(DisplayCtrl *dispPtr)
{
/*
* If already stopped, do nothing
*/
if (dispPtr->state == DISPLAY_STOPPED)
{
return XST_SUCCESS;
}
/*
* Disable the disp_ctrl core, and wait for the current frame to finish (the core cannot stop
* mid-frame)
*/
XVtc_DisableGenerator(&dispPtr->vtc);
/*
* Update Struct state
*/
dispPtr->state = DISPLAY_STOPPED;
//TODO: consider stopping the clock here, perhaps after a check to see if the VTC is finished
return XST_SUCCESS;
}
/* ------------------------------------------------------------ */
/*** DisplayStart(DisplayCtrl *dispPtr)
**
** Parameters:
** dispPtr - Pointer to the initialized DisplayCtrl struct
**
** Return Value: int
** XST_SUCCESS if successful, XST_FAILURE otherwise
**
** Errors:
**
** Description:
** Starts the display.
**
*/
int DisplayStart(DisplayCtrl *dispPtr)
{
XVtc_Timing vtcTiming;
XVtc_SourceSelect SourceSelect;
xdbg_printf(XDBG_DEBUG_GENERAL, "display start entered\n\r");
/*
* If already started, do nothing
*/
if (dispPtr->state == DISPLAY_RUNNING)
{
return XST_SUCCESS;
}
/*
* Configure the vtc core with the display mode timing parameters
*/
vtcTiming.HActiveVideo = dispPtr->vMode.width; /**< Horizontal Active Video Size */
vtcTiming.HFrontPorch = dispPtr->vMode.hps - dispPtr->vMode.width; /**< Horizontal Front Porch Size */
vtcTiming.HSyncWidth = dispPtr->vMode.hpe - dispPtr->vMode.hps; /**< Horizontal Sync Width */
vtcTiming.HBackPorch = dispPtr->vMode.hmax - dispPtr->vMode.hpe + 1; /**< Horizontal Back Porch Size */
vtcTiming.HSyncPolarity = dispPtr->vMode.hpol; /**< Horizontal Sync Polarity */
vtcTiming.VActiveVideo = dispPtr->vMode.height; /**< Vertical Active Video Size */
vtcTiming.V0FrontPorch = dispPtr->vMode.vps - dispPtr->vMode.height; /**< Vertical Front Porch Size */
vtcTiming.V0SyncWidth = dispPtr->vMode.vpe - dispPtr->vMode.vps; /**< Vertical Sync Width */
vtcTiming.V0BackPorch = dispPtr->vMode.vmax - dispPtr->vMode.vpe + 1;; /**< Horizontal Back Porch Size */
vtcTiming.V1FrontPorch = dispPtr->vMode.vps - dispPtr->vMode.height; /**< Vertical Front Porch Size */
vtcTiming.V1SyncWidth = dispPtr->vMode.vpe - dispPtr->vMode.vps; /**< Vertical Sync Width */
vtcTiming.V1BackPorch = dispPtr->vMode.vmax - dispPtr->vMode.vpe + 1;; /**< Horizontal Back Porch Size */
vtcTiming.VSyncPolarity = dispPtr->vMode.vpol; /**< Vertical Sync Polarity */
vtcTiming.Interlaced = 0; /**< Interlaced / Progressive video */
/* Setup the VTC Source Select config structure. */
/* 1=Generator registers are source */
/* 0=Detector registers are source */
memset((void *)&SourceSelect, 0, sizeof(SourceSelect));
SourceSelect.VBlankPolSrc = 1;
SourceSelect.VSyncPolSrc = 1;
SourceSelect.HBlankPolSrc = 1;
SourceSelect.HSyncPolSrc = 1;
SourceSelect.ActiveVideoPolSrc = 1;
SourceSelect.ActiveChromaPolSrc= 1;
SourceSelect.VChromaSrc = 1;
SourceSelect.VActiveSrc = 1;
SourceSelect.VBackPorchSrc = 1;
SourceSelect.VSyncSrc = 1;
SourceSelect.VFrontPorchSrc = 1;
SourceSelect.VTotalSrc = 1;
SourceSelect.HActiveSrc = 1;
SourceSelect.HBackPorchSrc = 1;
SourceSelect.HSyncSrc = 1;
SourceSelect.HFrontPorchSrc = 1;
SourceSelect.HTotalSrc = 1;
XVtc_SelfTest(&(dispPtr->vtc));
XVtc_RegUpdateEnable(&(dispPtr->vtc));
XVtc_SetGeneratorTiming(&(dispPtr->vtc), &vtcTiming);
XVtc_SetSource(&(dispPtr->vtc), &SourceSelect);
/*
* Enable VTC core, releasing backpressure on VDMA
*/
XVtc_EnableGenerator(&dispPtr->vtc);
dispPtr->state = DISPLAY_RUNNING;
return XST_SUCCESS;
}
/* ------------------------------------------------------------ */
/*** DisplayInitialize(DisplayCtrl *dispPtr,u16 vtcId)
**
** Parameters:
** dispPtr - Pointer to the struct that will be initialized
** vtcId - Device ID of the VTC core as found in xparameters.h
**
** Return Value: int
** XST_SUCCESS if successful, XST_FAILURE otherwise
**
** Errors:
**
** Description:
** Initializes the driver struct for use.
**
*/
int DisplayInitialize(DisplayCtrl *dispPtr, u16 vtcId)
{
int Status;
XVtc_Config *vtcConfig;
/*
* Initialize all the fields in the DisplayCtrl struct
*/
dispPtr->state = DISPLAY_STOPPED;
dispPtr->vMode = VMODE_1280x720;//原代码为VMODE_800x480;
/* Initialize the VTC driver so that it's ready to use look up
* configuration in the config table, then initialize it.
*/
vtcConfig = XVtc_LookupConfig(vtcId);
/* Checking Config variable */
if (NULL == vtcConfig) {
return (XST_FAILURE);
}
Status = XVtc_CfgInitialize(&(dispPtr->vtc), vtcConfig, vtcConfig->BaseAddress);
/* Checking status */
if (Status != (XST_SUCCESS)) {
return (XST_FAILURE);
}
return XST_SUCCESS;
}
/* ------------------------------------------------------------ */
/*** DisplaySetMode(DisplayCtrl *dispPtr, const VideoMode *newMode)
**
** Parameters:
** dispPtr - Pointer to the initialized DisplayCtrl struct
** newMode - The VideoMode struct describing the new mode.
**
** Return Value: int
** XST_SUCCESS if successful, XST_FAILURE otherwise
**
** Errors:
**
** Description:
** Changes the resolution being output to the display. If the display
** is currently started, it is automatically stopped (DisplayStart must
** be called again).
**
*/
int DisplaySetMode(DisplayCtrl *dispPtr, const VideoMode *newMode)
{
int Status;
/*
* If currently running, stop
*/
if (dispPtr->state == DISPLAY_RUNNING)
{
Status = DisplayStop(dispPtr);
if (Status != XST_SUCCESS)
{
xdbg_printf(XDBG_DEBUG_GENERAL, "Cannot change mode, unable to stop display %d\r\n", Status);
return XST_FAILURE;
}
}
dispPtr->vMode = *newMode;
return XST_SUCCESS;
}
/*
//获取LCD屏ID
//PG6=R7(M0);PI2=G7(M1);PI7=B7(M2);
//M2:M1:M0
//0 :0 :0 //4.3寸480*272 RGB屏,ID=0X4342
//0 :0 :1 //7寸800*480 RGB屏,ID=0X7084
//0 :1 :0 //7寸1024*600 RGB屏,ID=0X7016
//1 :0 :0 //4.3寸800*480 RGB屏,ID=0X4384
//1 :0 :1 //10.1寸1280*800 RGB屏,ID=0X1018
//返回值:LCD ID:0,非法;其他值,ID;
u16 LTDC_PanelID_Read(XGpio * axi_gpio_inst,unsigned chanel)
{
u32 idx=0;
idx = XGpio_DiscreteRead(axi_gpio_inst,chanel); //读取按键数据
switch(idx)
{
case 0:return 0x4342; //4.3寸屏,480*272分辨率
case 1:return 0x7084; //7寸屏,800*480分辨率
case 2:return 0x7016; //7寸屏,1024*600分辨率
case 4:return 0x4384; //4.3寸屏,800*480分辨率
case 5:return 0x1018; //10.1寸屏,1280*800分辨率
default:return 0;
}
}
*/

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display_ctrl.h

#ifndef DISPLAY_CTRL_H_
#define DISPLAY_CTRL_H_
/* ------------------------------------------------------------ */
/* Include File Definitions */
/* ------------------------------------------------------------ */
#include "xil_types.h"
#include "xvtc.h"
#include "lcd_modes.h"
//#include "xgpio.h"
/* ------------------------------------------------------------ */
/* Miscellaneous Declarations */
/* ------------------------------------------------------------ */
#define BIT_DISPLAY_RED 16
#define BIT_DISPLAY_GREEN 8
#define BIT_DISPLAY_BLUE 0
/*
* This driver currently supports frames.
*/
#define DISPLAY_NUM_FRAMES 1
/* ------------------------------------------------------------ */
/* General Type Declarations */
/* ------------------------------------------------------------ */
typedef enum {
DISPLAY_STOPPED = 0,
DISPLAY_RUNNING = 1
} DisplayState;
typedef struct {
XVtc vtc; /*VTC driver struct*/
VideoMode vMode; /*Current Video mode*/
double pxlFreq; /* Frequency of clock currently being generated */
DisplayState state; /* Indicates if the Display is currently running */
} DisplayCtrl;
/* ------------------------------------------------------------ */
/* Procedure Declarations */
/* ------------------------------------------------------------ */
int DisplayStop(DisplayCtrl *dispPtr);
int DisplayStart(DisplayCtrl *dispPtr);
int DisplayInitialize(DisplayCtrl *dispPtr,u16 vtcId);
int DisplaySetMode(DisplayCtrl *dispPtr, const VideoMode *newMode);
int DisplayChangeFrame(DisplayCtrl *dispPtr, u32 frameIndex);
//u16 LTDC_PanelID_Read(XGpio * axi_gpio_inst, unsigned chanel);
/* ------------------------------------------------------------ */
/************************************************************************/
#endif /* DISPLAY_CTRL_H_ */

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lcd_modes.h

#ifndef LCD_MODES_H_
#define LCD_MODES_H_
typedef struct {
char label[64]; /* Label describing the resolution */
u32 width; /*Width of the active video frame*/
u32 height; /*Height of the active video frame*/
u32 hps; /*Start time of Horizontal sync pulse, in pixel clocks (active width + H. front porch)*/
u32 hpe; /*End time of Horizontal sync pulse, in pixel clocks (active width + H. front porch + H. sync width)*/
u32 hmax; /*Total number of pixel clocks per line (active width + H. front porch + H. sync width + H. back porch) */
u32 hpol; /*hsync pulse polarity*/
u32 vps; /*Start time of Vertical sync pulse, in lines (active height + V. front porch)*/
u32 vpe; /*End time of Vertical sync pulse, in lines (active height + V. front porch + V. sync width)*/
u32 vmax; /*Total number of lines per frame (active height + V. front porch + V. sync width + V. back porch) */
u32 vpol; /*vsync pulse polarity*/
double freq; /*Pixel Clock frequency*/
} VideoMode;
static const VideoMode VMODE_480x272 = {
.label = "480x272@60Hz",
.width = 480,
.height = 272,
.hps = 482,
.hpe = 523,
.hmax = 525,
.hpol = 0,
.vps = 274,
.vpe = 284,
.vmax = 286,
.vpol = 0,
.freq = 9
};
static const VideoMode VMODE_640x480 = {
.label = "640x480@60Hz",
.width = 640,
.height = 480,
.hps = 656,
.hpe = 752,
.hmax = 799,
.hpol = 0,
.vps = 490,
.vpe = 492,
.vmax = 524,
.vpol = 0,
.freq = 25.12
};
static const VideoMode VMODE_800x480 = {
.label = "800x480@60Hz",
.width = 800,
.height= 480,
.hps = 840,
.hpe = 968,
.hmax = 1056,
.hpol = 0,
.vps = 490,
.vpe = 492,
.vmax = 525,
.vpol = 0,
.freq = 33.0
};
static const VideoMode VMODE_800x600 = {
.label = "800x600@60Hz",
.width = 800,
.height = 600,
.hps = 840,
.hpe = 968,
.hmax = 1055,
.hpol = 1,
.vps = 601,
.vpe = 605,
.vmax = 627,
.vpol = 1,
.freq = 40.0
};
static const VideoMode VMODE_1024x600 = {
.label = "1024x600@60Hz",
.width = 1024,
.height = 600,
.hps = 1164,
.hpe = 1184,
.hmax = 1344,
.hpol = 0,
.vps = 620,
.vpe = 623,
.vmax = 635,
.vpol = 0,
.freq = 50.0
};
static const VideoMode VMODE_1280x800 = {
.label = "1280x800@60Hz",
.width = 1280,
.height = 800,
.hps = 1360,
.hpe = 1370,
.hmax = 1440,
.hpol = 0,
.vps = 810,
.vpe = 813,
.vmax = 823,
.vpol = 0,
.freq = 70.0
};
static const VideoMode VMODE_1280x1024 = {
.label = "1280x1024@60Hz",
.width = 1280,
.height = 1024,
.hps = 1328,
.hpe = 1440,
.hmax = 1687,
.hpol = 1,
.vps = 1025,
.vpe = 1028,
.vmax = 1065,
.vpol = 1,
.freq = 108.0
};
static const VideoMode VMODE_1280x720 = {
.label = "1280x720@60Hz",
.width = 1280,
.height = 720,
.hps = 1390,
.hpe = 1430,
.hmax = 1649,
.hpol = 1,
.vps = 725,
.vpe = 730,
.vmax = 749,
.vpol = 1,
.freq = 74.25, //74.2424 is close enough
};
static const VideoMode VMODE_1920x1080 = {
.label = "1920x1080@60Hz",
.width = 1920,
.height = 1080,
.hps = 2008,
.hpe = 2052,
.hmax = 2199,
.hpol = 1,
.vps = 1084,
.vpe = 1089,
.vmax = 1124,
.vpol = 1,
.freq = 148.5 //148.57 is close enough
};
#endif /* LCD_MODES_H_ */

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（3）main.c

#include "stdio.h"
#include "xil_printf.h"
#include "xparameters.h"
#include "xil_cache.h"
#include "xaxivdma.h"
#include "vdma_api/vdma_api.h"
#include "display_ctrl/display_ctrl.h"
#include "xclk_wiz.h"
#include "clk_wiz/clk_wiz.h"
#include "sleep.h"
//======================宏定义======================//
#define VDMA_ID XPAR_AXIVDMA_0_DEVICE_ID //VDMA器件ID
#define VTC_ID XPAR_VTC_0_DEVICE_ID //VTC器件ID
#define CLK_WIZ_ID XPAR_CLK_WIZ_0_DEVICE_ID //时钟IP核器件ID
#define DDR_BASE_ADDR XPAR_PS7_DDR_0_S_AXI_BASEADDR //DDR的基地址（在xparameters.h或lscript.ld查看）
#define MEM_BASE_ADDR (DDR_BASE_ADDR + 0x01000000) //DDR中存储数据缓存的基地址（确保在堆栈已使用DDR范围之后，lscript.ld查看）
#define PIXEL_BYTE 3 //一个像素数据所占字节（RGB888 3字节）
//==================函数、变量声明==================//
XClk_Wiz CLK_WIZ; //时钟IP核实例
XAxiVdma Vdma; //VDMA实例
VideoMode vd_mode; //lcd_modes.h中定义的结构体，包含视频分辨率格式的各个参数
DisplayCtrl dispCtrl; //display_ctrl.h中定义的结构体，包含视频分辨率格式的各个参数
static void Set_Mode(int mode);//调整输出分辨率
static void Write_Colorbar(); //向DDR数据缓存区域写数据
//======================主函数======================//
int main()
{
xil_printf("VDMA VGA Colorbar Test\r\n");
for (int i=1; i<=3; i++)
{
//调整输出分辨率
Set_Mode(i);
//配置时钟IP输出频率（单位MHz）
clk_wiz_cfg(CLK_WIZ_ID, vd_mode.freq);
xil_printf("%u,%u",vd_mode.width,vd_mode.height);
//配置并启动VDMA:（本例未使用中断）
//(VDMA实例指针，器件ID，图像宽度，图像高度，帧缓存起始地址，中断帧计数(传输多少帧产生中断)，中断使能，读写模式)
run_vdma_frame_buffer(&Vdma, VDMA_ID, vd_mode.width, vd_mode.height, (int)MEM_BASE_ADDR, 0, 0, ONLY_READ);
//初始化dispCtrl结构体(vd_mode默认1280x720@60)、初始化VTC
DisplayInitialize(&dispCtrl, VTC_ID);
//设置VTC时序参数
DisplaySetMode(&dispCtrl, &vd_mode);
//启动VTC时序生成
DisplayStart(&dispCtrl);
//向DDR数据缓存区域写数据（写彩条图像）
Write_Colorbar((u8*)MEM_BASE_ADDR , vd_mode.width, vd_mode.height);
sleep(5); //每隔5s切换一次分辨率
}
return 0;
}
//=============向DDR数据缓存区域写数据==============//
/*
* IMG_Buffer 指针，指向图像缓存的起始地址
* IMG_WIDTH 图像宽度
* IMG_HIGHT 图像高度
*/
void Write_Colorbar(u8 *IMG_Buffer, u32 IMG_WIDTH, u32 IMG_HIGHT)
{
u8 RGB_r, RGB_g, RGB_b;
int x, y, addr;
int segment_width = IMG_WIDTH / 7; // 每种颜色占1/7宽度
// 向DDR缓存区域写像素数据（RGB888）
for(y = 0; y < IMG_HIGHT; y++) {
for(x = 0; x < IMG_WIDTH; x++) {
// 根据x坐标确定颜色
if(x < segment_width * 1) { // 红色
RGB_r = 0xFF; RGB_g = 0x00; RGB_b = 0x00;
}
else if(x < segment_width * 2) { // 橙色
RGB_r = 0xFF; RGB_g = 0x4F; RGB_b = 0x00;
}
else if(x < segment_width * 3) { // 黄色
RGB_r = 0xFF; RGB_g = 0xBF; RGB_b = 0x00;
}
else if(x < segment_width * 4) { // 绿色
RGB_r = 0x00; RGB_g = 0xFF; RGB_b = 0x00;
}
else if(x < segment_width * 5) { // 青色
RGB_r = 0x00; RGB_g = 0xFF; RGB_b = 0xFF;
}
else if(x < segment_width * 6) { // 蓝色
RGB_r = 0x00; RGB_g = 0x00; RGB_b = 0xFF;
}
else { // 紫色
RGB_r = 0x7F; RGB_g = 0x00; RGB_b = 0xFF;
}
addr = y * (IMG_WIDTH * PIXEL_BYTE) + x * PIXEL_BYTE;
IMG_Buffer[addr + 0] = RGB_b; // B
IMG_Buffer[addr + 1] = RGB_g; // G
IMG_Buffer[addr + 2] = RGB_r; // R
}
}
// 刷新Cache，数据更新至内存
Xil_DCacheFlush();
xil_printf("Colorbar data ready\r\n");
}
//==================调整输出分辨率==================//
void Set_Mode(int mode)
{
switch(mode){
case 1 : vd_mode = VMODE_640x480; break;
case 2 : vd_mode = VMODE_800x600; break;
case 3 : vd_mode = VMODE_1280x720; break;
default : vd_mode = VMODE_1280x720; break;
}
}

复制代码

四、效果

下载后，隔断 5s 依次切换 640*480@60Hz、800x600@60Hz、1280*720@60Hz 三种分辨率进行彩条显示（gif 图片压缩后导致看起来有杂点很有点糊，实际显示器上面很清晰）

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ZYNQ条记（十九）：VDMA VGA 输出分辨率可调

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