FPGA实现BT.1120编码

研究了两天的BT1120规范，以及CEA-861-D视频时序，找到了一些对应关系(见我另外一篇文章《视频时序与BT1120的关系》)。于是写了如下的verilog代码，可对接sii9134芯片的行场内嵌方式，其中sii9134配置C代码如下：

void sii9134_init(void)
{
u8 u8Data = 0;
I2C_WriteByte(0x05, 0x08, 0x72); //value reg_addr device_addr

I2C_ReadByte(&u8Data, sizeof(u8), 0x33, 0x72);
I2C_WriteByte(u8Data & 0x8f, 0x33, 0x72);

I2C_WriteByte(0x6e, 0x40, 0x72);
I2C_WriteByte(0x28, 0x44, 0x72);
I2C_WriteByte(0x00, 0x45, 0x72);
I2C_WriteByte(0x05, 0x46, 0x72);
I2C_WriteByte(0x05, 0x47, 0x72);
I2C_WriteByte(0x30, 0x48, 0x72);

I2C_WriteByte(0x3d, 0x4a, 0x72);
}

FPGA实验板使用黑金的AV6045开发板。

FPGA端的bt1120 verilog代码如下(行场同步信号hsync和vsync为高电平有效)：

另外，如果发现像素数据为0xff或0x00则需要替换为0xfe和0x01，防止对端误判。（本文没有做这一步）

/**
* author : mkelehk@gmail.com
* time : 2017/8/28
* function : ycbcr4:2:2 embed_hs_vs encoder module, compatible bt.1120
*
* 定时基准码 <0xff 0x00 0x00 xxx>
* 其中xxx为如下的取值范围:
* 1 0 1 0 1 0 1 1 0 0 0xab(帧消隐期间,SAV内)
* 1 0 1 1 0 1 1 0 0 0 0xb6(帧消隐期间,EAV内)
* 1 0 0 0 0 0 0 0 0 0 0x80(视频有效区时间,SAV内)
* 1 0 0 1 1 1 0 1 0 0 0x9d(视频有效区时间,EAV内)
*/

`timescale 1ns / 100ps
module embed_hs_vs_enc(
input rst,

input yc422_pclk_i,
input [15:0] yc422_data_i,
input yc422_de_i,
input yc422_vs_i,
input yc422_hs_i,

//--------------------------------------------------------
//视频时序参数，由CPU 通过i2c配置得到
input [11:0] width_i, // l
input [11:0] height_i, //
input [11:0] hs_rising_to_de_i,
input [11:0] hor_total_g_i,
input [11:0] vs_rising_to_de_i, //L2
input [11:0] ver_total_g_i, //L6

//----------------------------------------------------------
input video_pararm_enable_i,
//----------------------------------------------------------

//bt.1120接口
output embed_hs_vs_pclk_o,
output reg[15:0] embed_hs_vs_yc422_o
);

//状态机状态
localparam INVAILD_BLANKING = 4'd0;
localparam VAILD_VIDEO = 4'd1;
localparam SYNC1_SAV = 4'd2;
localparam SYNC2_SAV = 4'd3;
localparam SYNC3_SAV = 4'd4;
localparam SYNC1_EAV = 4'd5;
localparam SYNC2_EAV = 4'd6;
localparam SYNC3_EAV = 4'd7;
localparam SAV_BKANKING = 4'd8;
localparam EAV_BKANKING = 4'd9;
localparam SAV_VIDEO = 4'd10;
localparam EAV_VIDEO = 4'd11;

//在行场消隐区填充STUFF
localparam STUFF = 16'h8010;

wire hs_rising; //rising or falling
wire vs_rising;

reg [11:0] vs_cnt;//场计数器
reg [11:0] hs_cnt;//行计数器

//复位信号要处理好，否则以下寄存器值未初始化
reg [11:0] width_g;
reg [11:0] height_g;
reg [11:0] hs_rising_to_de_g;
reg [11:0] hor_total_g;
reg [11:0] vs_rising_to_de_g;
reg [11:0] ver_total_g;

reg [3:0]state_cs;//当前状态需注意寄存器变量的位宽，防止溢出
reg [3:0]state_ns;//下一个状态

//对信号进行延时操作，打1拍
//reg[15:0] yc422_data_d1;
reg yc422_de_d1;
reg yc422_vs_d1;
reg yc422_hs_d1;

always @(posedge yc422_pclk_i)
begin
if(rst) begin
//yc422_data_d1 <= 16'h00;
yc422_de_d1 <= 1'b0;
yc422_vs_d1 <= 1'b0;
yc422_hs_d1 <= 1'b0;
end else begin
//yc422_data_d1 <= yc422_data_i;
yc422_de_d1 <= yc422_de_i;
yc422_vs_d1 <= yc422_vs_i;
yc422_hs_d1 <= yc422_hs_i;
end
end

assign embed_hs_vs_pclk_o = yc422_pclk_i;

assign hs_rising = ~yc422_hs_d1 & yc422_hs_i;
assign vs_rising = ~yc422_vs_d1 & yc422_vs_i;

always @(posedge yc422_pclk_i)
begin
if(rst) begin
width_g <= 12'd1920;
height_g <= 12'd1080;
hs_rising_to_de_g <= 12'd192;
hor_total_g <= 12'd2200;
vs_rising_to_de_g <= 12'd41;
ver_total_g <= 12'd1125;
end else if(video_pararm_enable_i)begin
width_g <= width_i;
height_g <= height_i;
hs_rising_to_de_g <= hs_rising_to_de_i;
hor_total_g <= hor_total_g_i;
vs_rising_to_de_g <= vs_rising_to_de_i;
ver_total_g <= ver_total_g_i;
end
end

//行计数
always @(posedge yc422_pclk_i)
begin
if(rst)
hs_cnt <= 0;
else if(hs_rising || video_pararm_enable_i)
hs_cnt <= 0;
else if(hs_cnt == hor_total_g - 1'b1)
hs_cnt <= 0;
else
hs_cnt <= hs_cnt + 1'b1;
end

//帧计数
always @(posedge yc422_pclk_i)
begin
if(rst)
vs_cnt <= 0;
else if(vs_rising || video_pararm_enable_i)
vs_cnt <= 0;
else if(hs_cnt == hor_total_g - 1'b1)
if(vs_cnt == ver_total_g - 1'b1)
vs_cnt <= 0;
else
vs_cnt <= vs_cnt + 1'b1;
else
vs_cnt <= vs_cnt;
end

always @(posedge yc422_pclk_i)
begin
if(rst)
state_cs <= INVAILD_BLANKING;
else
state_cs <= state_ns;
end

always @(*)
begin
case(state_cs)
INVAILD_BLANKING :
begin
if(hs_cnt == hs_rising_to_de_g - 3'd6) //SAV 提前4个时钟，因为SAV和EAV要包含4个时钟周期，并且补偿state_cs和第三段带来的2拍延时
state_ns = SYNC1_SAV;
else if(hs_cnt == hs_rising_to_de_g + width_g - 3'd2) //EAV 不需要提前4个时钟,但需要补偿state_cs和第三段带来的2拍延时
state_ns = SYNC1_EAV;
else
state_ns = INVAILD_BLANKING;
end

//SAV部分
SYNC1_SAV : state_ns = SYNC2_SAV;
SYNC2_SAV : state_ns = SYNC3_SAV;
SYNC3_SAV :
if((vs_cnt >= vs_rising_to_de_g - 1'b1) && (vs_cnt <= height_g + vs_rising_to_de_g - 1'b1))//VILD_VIDEO
state_ns = SAV_VIDEO;
else
state_ns = SAV_BKANKING;

//EAV部分
SYNC1_EAV : state_ns = SYNC2_EAV;
SYNC2_EAV : state_ns = SYNC3_EAV;
SYNC3_EAV :
if((vs_cnt >= vs_rising_to_de_g - 1'b1) && (vs_cnt <= height_g + vs_rising_to_de_g - 1'b1))//VILD_VIDEO
state_ns = EAV_VIDEO;
else
state_ns = EAV_BKANKING;

SAV_BKANKING : state_ns = INVAILD_BLANKING;
EAV_BKANKING : state_ns = INVAILD_BLANKING;
SAV_VIDEO : state_ns = VAILD_VIDEO;
EAV_VIDEO : state_ns = INVAILD_BLANKING;

VAILD_VIDEO :
if(hs_cnt == hs_rising_to_de_g + width_g - 1'b1 - 1'b1)
state_ns = SYNC1_EAV;//去EAV部分
else
state_ns = VAILD_VIDEO;
default :
state_ns = INVAILD_BLANKING;
endcase
end

always @(posedge yc422_pclk_i)
begin
if(rst)
embed_hs_vs_yc422_o <= STUFF;
else begin
if(state_cs == INVAILD_BLANKING)
embed_hs_vs_yc422_o <= STUFF;
else if(state_cs == VAILD_VIDEO)
embed_hs_vs_yc422_o <= yc422_data_i; //yc422_data_d1
else if((state_cs == SYNC1_SAV) || (state_cs == SYNC1_EAV))
embed_hs_vs_yc422_o <= 16'hffff;
else if((state_cs == SYNC2_SAV) || (state_cs == SYNC2_EAV))
embed_hs_vs_yc422_o <= 16'h0000;
else if((state_cs == SYNC3_SAV) || (state_cs == SYNC3_EAV))
embed_hs_vs_yc422_o <= 16'h0000;
else if(state_cs == SAV_BKANKING)
embed_hs_vs_yc422_o <= 16'habab;
else if(state_cs == EAV_BKANKING)
embed_hs_vs_yc422_o <= 16'hb6b6;
else if(state_cs == SAV_VIDEO)
embed_hs_vs_yc422_o <= 16'h8080;
else if(state_cs == EAV_VIDEO)
embed_hs_vs_yc422_o <= 16'h9d9d;
else
embed_hs_vs_yc422_o <= STUFF;
end
end

endmodule

   embed_hs_vs_enc U_embed_hs_vs_enc_0(
. rst(rst),

. yc422_pclk_i(video_clk_148m5),
. yc422_data_i({yc_c,yc_y}),
. yc422_de_i(yc_de),
. yc422_vs_i(yc_vs),
. yc422_hs_i(yc_hs),

//--------------------------------------------------------
//视频时序参数，由CPU 通过i2c配置得到
. width_i(12'd1920), // l
. height_i(12'd1080), //
. hs_rising_to_de_i(12'd192),
. hor_total_g_i(12'd2200),
. vs_rising_to_de_i(12'd41), //L2
. ver_total_g_i(12'd1125), //L6

//----------------------------------------------------------
. video_pararm_enable_i(video_pararm_enable),
//----------------------------------------------------------

//bt.1120接口
. embed_hs_vs_pclk_o(bt1120_clk),
. embed_hs_vs_yc422_o(bt1120_yc)
   );