1. 概述
HDMI英文名为High Definition Multimedia Interface，是一种数字化视频、音频接口。 现已
广泛应用于高清数字电视、PC显示器等产品中。
这里我们使用Silicon Image公司的SiI9134作为HDMI发送芯片，支持HDMI 1.3标准。
2. 设计框图
视频源由FPGA内部产生，sii9134的配置通过I2C模块完成。这里以720P60为例完成设计。
3. Sii9134配置
这里将Sii9134配置成YCbCr422输入，RGB444输出模式。
void sii9134_init()
{
sccb_senddata(0x72,0x05,0x01); //reset all sections
sccb_senddata(0x72,0x05,0x00); //disable reset
sccb_senddata(0x72,0x08,0x37); //VSYNC and HSYNC, 24bit, rising edge, normal operation
sccb_senddata(0x72,0x0c,0x00);
sccb_senddata(0x72,0x0d,0x01);
sccb_senddata(0x72,0x4B,0x00); //Blue
sccb_senddata(0x72,0x4C,0x00); //Green
sccb_senddata(0x72,0x4D,0xff); //Red
sccb_senddata(0x72,0x82,0x25); //FPLL*IDCK, enable internal source termination
sccb_senddata(0x72,0x83,0x19); //HDMI PLL/2, PLL filter feedback/4, PLL filter front/2
sccb_senddata(0x72,0x84,0x31); //50uA, PLL filter post/2
sccb_senddata(0x72,0x85,0x01); //HDMI transmitter PLL front/2
sccb_senddata(0x72,0x32,0x04); //h-blank
sccb_senddata(0x72,0x33,0x41); //enable DE, positive polarity, left-blank(370 pixels)
sccb_senddata(0x72,0x34,0x19); //v-blank(30 lines)
sccb_senddata(0x72,0x36,0x00); //the width of active display
sccb_senddata(0x72,0x37,0x05); //the width of active display(1280)
sccb_senddata(0x72,0x38,0xD0); //the height of active display
sccb_senddata(0x72,0x39,0x02); //the height of active display(720)
sccb_senddata(0x72,0x3E,0x00);
sccb_senddata(0x72,0x40,0x6e);
sccb_senddata(0x72,0x41,0x00);
sccb_senddata(0x72,0x44,0x29);
sccb_senddata(0x72,0x45,0x00);
sccb_senddata(0x72,0x46,0x05);
sccb_senddata(0x72,0x47,0x06);
sccb_senddata(0x72,0x48,0x30);
sccb_senddata(0x72,0x49,0x00);
sccb_senddata(0x72,0x4a,0x3c);
////////////////////////////////////////////////
sccb_senddata(0x7a,0x01,0x02);
sccb_senddata(0x7a,0x02,0x01);
sccb_senddata(0x7a,0x03,0x00);
sccb_senddata(0x7a,0x04,0x18);
sccb_senddata(0x7a,0x05,0x00);
sccb_senddata(0x7a,0x14,0x11);
sccb_senddata(0x7a,0x1D,0x40);
sccb_senddata(0x7a,0x21,0x02);
sccb_senddata(0x7a,0x22,0x2B);
sccb_senddata(0x7a,0x2F,0x01);
sccb_senddata(0x7a,0x40,0x82);
sccb_senddata(0x7a,0x41,0x02);
sccb_senddata(0x7a,0x42,0x0d);
sccb_senddata(0x7a,0x43,0x59);
sccb_senddata(0x7a,0x44,0x11);
sccb_senddata(0x7a,0x45,0x28);
sccb_senddata(0x7a,0x46,0x00);
sccb_senddata(0x7a,0x47,0x04);
sccb_senddata(0x7a,0x48,0x00);
sccb_senddata(0x7a,0x49,0x00);
sccb_senddata(0x7a,0x4A,0x00);
sccb_senddata(0x7a,0x4B,0xD1);
sccb_senddata(0x7a,0x4C,0x02);
sccb_senddata(0x7a,0x4D,0x00);
sccb_senddata(0x7a,0x4E,0x00);
sccb_senddata(0x7a,0x4F,0x01);
sccb_senddata(0x7a,0x50,0x05);
sccb_senddata(0x7a,0x51,0x00);
sccb_senddata(0x7a,0x52,0x00);
sccb_senddata(0x7a,0x80,0x84);
sccb_senddata(0x7a,0x81,0x01);
sccb_senddata(0x7a,0x82,0x0a);
sccb_senddata(0x7a,0x83,0x70);
sccb_senddata(0x7a,0x84,0x01);
sccb_senddata(0x7a,0x85,0x00);
sccb_senddata(0x7a,0x86,0x00);
sccb_senddata(0x7a,0x87,0x00);
sccb_senddata(0x7a,0x88,0x00);
sccb_senddata(0x7a,0x89,0x00);
sccb_senddata(0x7a,0x8a,0x00);
sccb_senddata(0x7a,0x8b,0x00);
sccb_senddata(0x7a,0x8c,0x00);
sccb_senddata(0x7a,0x8d,0x00);
sccb_senddata(0x7a,0x3e,0x33);
}4. FPGA逻辑设计
FPGA逻辑完成视频源生成、HDMI配置、RGB转YCbCr功能。下面表格给出RGB转YC的公式。
Video Format |
Formulas |
576p |
Y = 0.299R′ + 0.587G′ + 0.114B′ |
480p |
|
240p |
|
720p |
Y = 0.213R′ + 0.715G′ + 0.072B′ |
1080p |
//file name: hdmi_vid_gen.v
//author: shugen.yin
//date: 2016.9.21
//function: hdmi video generation
//log:
module hdmi_vid_gen(
input clk, //74.25MHz
input rst_n,
output hdmi_clk,
output hdmi_txde,
output hdmi_hs,
output hdmi_vs,
output [15:0] hdmi_data
);
parameter IMG_HDISP = 16'd1280;
parameter IMG_VDISP = 16'd720;
parameter H_OFFSET = 0;
wire pclk;
assign pclk = clk;
assign hdmi_clk = pclk;
assign hdmi_hs = hsync;
assign hdmi_txde = data_valid;
assign hdmi_vs = vsync;
assign hdmi_data = data;
reg [11:0] vcnt;
reg [15:0] hcnt;
reg vsync;
reg hsync;
reg data_valid;
reg [15:0] data;
reg [7:0] red;
reg [7:0] green;
reg [7:0] blue;
always @(posedge pclk)
if(hcnt>=(IMG_HDISP+259)) //720p
hcnt <= 0;
else
hcnt <= hcnt + 1'b1;
always @(posedge pclk)
if(hcnt>=(IMG_HDISP+259))
if(vcnt>=(IMG_VDISP+24))
vcnt <= 0;
else
vcnt <= vcnt + 1'b1;
else
vcnt <= vcnt;
always @(posedge pclk)
if((hcnt>=IMG_HDISP+H_OFFSET) & (hcnt<=(IMG_HDISP+H_OFFSET+32)) & (vcnt>=0 | (vcnt=(IMG_VDISP+2))
vsync <= 1'b1;
else
vsync <= 1'b0;
reg cbcr_reg;
always @(posedge pclk)
if(vsync)
begin
data <= 0;
cbcr_reg <= 0;
red <= 0;
green <= 0;
blue <= 0;
end
else if((hcnt>=0) & (hcnt<(IMG_HDISP+0)) & (vcnt>=0) & (vcnt<(0+IMG_VDISP/4)))
begin
if(~cbcr_reg)
begin
data[7:0] <= y;
data[15:8] <= cb;
end
else
begin
data[7:0] <= y;
data[15:8] <= cr;
end
cbcr_reg <= ~cbcr_reg;
red <= 8'hf0;
green <= 8'hf0;
blue <= 8'h00;
end
else if((hcnt>=0) & (hcnt<(IMG_HDISP+0)) & (vcnt>=(0+IMG_VDISP/4)) & (vcnt<(0+2*IMG_VDISP/4)))
begin
if(~cbcr_reg)
begin
data[7:0] <= y;
data[15:8] <= cb;
end
else
begin
data[7:0] <= y;
data[15:8] <= cr;
end
cbcr_reg <= ~cbcr_reg;
red <= 8'hf0;
green <= 8'h00;
blue <= 8'h00;
end
else if((hcnt>=0) & (hcnt<(IMG_HDISP+0)) & (vcnt>=(0+2*IMG_VDISP/4)) & (vcnt<(0+3*IMG_VDISP/4)))
begin
if(~cbcr_reg)
begin
data[7:0] <= y;
data[15:8] <= cb;
end
else
begin
data[7:0] <= y;
data[15:8] <= cr;
end
cbcr_reg <= ~cbcr_reg;
red <= 8'h00;
green <= 8'hf0;
blue <= 8'h00;
end
else if((hcnt>=0) & (hcnt<(IMG_HDISP+0)) & (vcnt>=(0+3*IMG_VDISP/4)) & (vcnt<(0+IMG_VDISP)))
begin
if(~cbcr_reg)
begin
data[7:0] <= y;
data[15:8] <= cb;
end
else
begin
data[7:0] <= y;
data[15:8] <= cr;
end
cbcr_reg <= ~cbcr_reg;
red <= 8'h00;
green <= 8'h00;
blue <= 8'hf0;
end
else
begin
data <= 0;
cbcr_reg <= 0;
red <= 0;
green <= 0;
blue <= 0;
end
always @(posedge pclk)
if(vsync)
data_valid <= 0;
else if((hcnt>=0) & (hcnt<(IMG_HDISP+0)) & (vcnt>=0) & (vcnt<(0+IMG_VDISP/4)))
data_valid <= 1;
else if((hcnt>=0) & (hcnt<(IMG_HDISP+0)) & (vcnt>=(0+IMG_VDISP/4)) & (vcnt<(0+2*IMG_VDISP/4)))
data_valid <= 1;
else if((hcnt>=0) & (hcnt<(IMG_HDISP+0)) & (vcnt>=(0+2*IMG_VDISP/4)) & (vcnt<(0+3*IMG_VDISP/4)))
data_valid <= 1;
else if((hcnt>=0) & (hcnt<(IMG_HDISP+0)) & (vcnt>=(0+3*IMG_VDISP/4)) & (vcnt<(0+IMG_VDISP)))
data_valid <= 1;
else
data_valid <= 0;
wire [7:0] y;
wire [7:0] cb;
wire [7:0] cr;
rgb2ycbcr rgb2ycbcr_inst
(
.clk(pclk) , // input clk_sig
.rst_n(rst_n) , // input rst_n_sig
.red(red) , // input [7:0] red_sig
.green(green) , // input [7:0] green_sig
.blue(blue) , // input [7:0] blue_sig
.y(y) , // output [7:0] y_sig
.cb(cb) , // output [7:0] cb_sig
.cr(cr) // output [7:0] cr_sig
);
endmodule 5. 最终结果
在显示器上显示1280*720@60帧的彩条视频。
