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1 概述
本文介绍基于freescale i.MX6 高清视频采集方案的技术详解，高清视频输入可以为HDMI、DVI或者VGA的方式。分辨率支持1600*1200@60、1920*1080@60、1280x720@60HZ等多种。视频解码芯片采用ADI的ADV7441A。
实现低成本、高性能、高集成度的视频采集产品。
包括硬件设计详解、软件设计详解。
2 功能列表
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序号
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功能
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详细说明
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1
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处理器
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Freescale’s i.MX6 Dual CPUs: ARM Cortex A9, each @ 1GHz
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2
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内存
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1GB DDR3 1066MHz
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3
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存储器
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Emmc NAND FLASH 4GB
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4
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TF卡
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TF卡，
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5
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以太网
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10M/100/100M以太网
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6
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USB HOST
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USB HOST，USB 2.0
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7
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固态硬盘
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Msata硬盘
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8
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高清视频输入
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支持一路VGA或者HDMI或者DVI高清视频输入，分辨率为1600*1200@60或者1920*1080@60或者1280x720@60HZ等
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9
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H.264或者MPEG4编码
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支持H.264或者MPEG4编码，分辨率至少为1600*1200@30或者1920*1080@30或者1280x720@60HZ等
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10
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操作系统
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Linux 3.0.15
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11
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工作温度
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-40℃-70℃
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3 系统框图
产品系统主要包括i.MX6 Dual处理器、以太网、高清视频解码芯片、固体硬盘、USB HOST以及调试串口。
功能见如下框图
4 软件设计
4.1 CSI框图
4.2 ADV7441A I2C寄存器设置
42 03 0C ; Disable TOD
42 05 02 ; Prim_Mode =010b for automatic graphics mode
42 06 07 ; VID_STD=00111b for automatic graphics mode
42 1D 40 ; Disable TRI_LLC
42 3C A8 ; SOG Sync level for atenuated sync, PLL Qpump to default
42 37 00 ; PCLK Polarity
42 47 0A ; Enable Automatic PLL_Qpump and VCO Range
42 68 F2 ; Auto CSC, RGB Out
42 6B F2 ; Setup CPOP_SEL & DE Enable
42 7B 1D ; Turn off EAV and SAV codes
42 7C 00 ; HS/VS Positive
42 7E 03 ; HS Adjust
42 7F 88 ; VS Adjust
42 F4 3F ; Max Drive Strength
42 87 E8 ; Enable Manual PLL Divider Ratio 0x870 = 2160
42 88 70 ; Set PLL Divider Ratio
42 8C 07 ; HS adjust
42 8D 5A ; HS adjust
42 8E 87 ; VBI Adjust
42 8F 01 ; Set Free Run Line Length 0x17E = 382
42 90 7E ; Set Free Run Line Length
42 AB 4E ; Set Line Count Max 0x4E2 = 1250
42 AC 20 ; Set Line Count Max
42 B5 08 ; Deglitch Filter adjust
42 91 10 ; Progressive
4.3 引脚定义
static iomux_v3_cfg_t mx6q_sabresd_csi1_sensor_pads[] = {
/* IPU2 tvin */
MX6Q_PAD_EIM_DA0__IPU2_CSI1_D_9,
MX6Q_PAD_EIM_DA1__IPU2_CSI1_D_8,
MX6Q_PAD_EIM_DA2__IPU2_CSI1_D_7,
MX6Q_PAD_EIM_DA3__IPU2_CSI1_D_6,
MX6Q_PAD_EIM_DA4__IPU2_CSI1_D_5,
MX6Q_PAD_EIM_DA5__IPU2_CSI1_D_4,
MX6Q_PAD_EIM_DA6__IPU2_CSI1_D_3,
MX6Q_PAD_EIM_DA7__IPU2_CSI1_D_2,
MX6Q_PAD_EIM_EB2__IPU2_CSI1_D_19,
MX6Q_PAD_EIM_D16__IPU2_CSI1_D_18,
MX6Q_PAD_EIM_D18__IPU2_CSI1_D_17,
MX6Q_PAD_EIM_D19__IPU2_CSI1_D_16,
MX6Q_PAD_EIM_D20__IPU2_CSI1_D_15,
MX6Q_PAD_EIM_D26__IPU2_CSI1_D_14,
MX6Q_PAD_EIM_D27__IPU2_CSI1_D_13,
MX6Q_PAD_EIM_D28__IPU2_CSI1_D_12,
MX6Q_PAD_EIM_D17__IPU2_CSI1_PIXCLK,
MX6Q_PAD_EIM_EB3__IPU2_CSI1_HSYNC,
MX6Q_PAD_EIM_D29__IPU2_CSI1_VSYNC,
MX6Q_PAD_EIM_D31__GPIO_3_31, /* tvin reset , low */
};
4.4 adv7441a复位和CPU相应寄存器初始化
#define SABRESD_TVIN_REST IMX_GPIO_NR(3, 31)
static void mx6q_csi1_io_init(void)
{
mxc_iomux_v3_setup_multiple_pads(mx6q_sabresd_csi1_sensor_pads,
ARRAY_SIZE(mx6q_sabresd_csi1_sensor_pads));
/* tvin reset */
gpio_request(SABRESD_TVIN_REST, "tvin-rest");
gpio_direction_output(SABRESD_TVIN_REST, 1);
gpio_direction_output(SABRESD_TVIN_REST, 0);
msleep(10);
gpio_direction_output(SABRESD_TVIN_REST, 1);
/* For MX6Q:
* GPR1 bit19 and bit20 meaning:
* Bit19: 0 - Enable mipi to IPU1 CSI0
* virtual channel is fixed to 0
* 1 - Enable parallel interface to IPU1 CSI0
* Bit20: 0 - Enable mipi to IPU2 CSI1
* virtual channel is fixed to 3
* 1 - Enable parallel interface to IPU2 CSI1
* IPU1 CSI1 directly connect to mipi csi2,
* virtual channel is fixed to 1
* IPU2 CSI0 directly connect to mipi csi2,
* virtual channel is fixed to 2
* For MX6DL:
* GPR13 bit 0-2 IPU_CSI0_MUX
* 000 MIPI_CSI0
* 100 IPU CSI0
if (cpu_is_mx6q())
mxc_iomux_set_gpr_register(1, 20, 1, 1);
// CPU工作在IPU2 CSI1
else if (cpu_is_mx6dl())
mxc_iomux_set_gpr_register(13, 0, 3, 4);
}
4.5 V4L主设备驱动
static int mxc_v4l2_s_param(cam_data *cam, struct v4l2_streamparm *parm)
if (ifparm.if_type == V4L2_IF_TYPE_BT656) {
if (ifparm.u.bt656.clock_curr == 0) {
csi_param.clk_mode = IPU_CSI_CLK_MODE_CCIR656_INTERLACED;
} else {
if (cam->device_type != 1)
csi_param.clk_mode = IPU_CSI_CLK_MODE_GATED_CLK;
else
csi_param.clk_mode = IPU_CSI_CLK_MODE_CCIR656_PROGRESSIVE;
}
if (ifparm.u.bt656.mode == V4L2_IF_TYPE_BT656_MODE_NOBT_8BIT) {
csi_param.data_width = IPU_CSI_DATA_WIDTH_8;
} else if (ifparm.u.bt656.mode
== V4L2_IF_TYPE_BT656_MODE_NOBT_10BIT) {
csi_param.data_width = IPU_CSI_DATA_WIDTH_10;
} else {
csi_param.data_width = IPU_CSI_DATA_WIDTH_8;
}
csi_param.Vsync_pol = ifparm.u.bt656.nobt_vs_inv;
csi_param.Hsync_pol = ifparm.u.bt656.nobt_hs_inv;
csi_param.pixclk_pol = ifparm.u.bt656.latch_clk_inv;
csi_param.ext_vsync = ifparm.u.bt656.bt_sync_correct;
} if (ifparm.if_type == V4L2_IF_TYPE_BT1120) {
{
if (ifparm.u.bt1120.clock_curr == 0) {
csi_param.clk_mode = IPU_CSI_CLK_MODE_CCIR1120_INTERLACED_SDR;
}
else {
if (cam->device_type != 1)
csi_param.clk_mode = IPU_CSI_CLK_MODE_GATED_CLK;
else
csi_param.clk_mode = IPU_CSI_CLK_MODE_CCIR1120_PROGRESSIVE_SDR;
}
}
if (ifparm.u.bt1120.mode == V4L2_IF_TYPE_BT1120_MODE_BT_8BIT) {
csi_param.data_width = IPU_CSI_DATA_WIDTH_8;
} else if (ifparm.u.bt1120.mode
== V4L2_IF_TYPE_BT1120_MODE_BT_16BIT) {
csi_param.data_width = IPU_CSI_DATA_WIDTH_16;
} else {
csi_param.data_width = IPU_CSI_DATA_WIDTH_8;
}
csi_param.Vsync_pol = ifparm.u.bt1120.nobt_vs_inv;
csi_param.Hsync_pol = ifparm.u.bt1120.nobt_hs_inv;
csi_param.pixclk_pol = ifparm.u.bt1120.latch_clk_inv;
csi_param.ext_vsync = ifparm.u.bt1120.bt_sync_correct;
}
4.6 adv7441a_probe函数
static int adv7441a_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int ret = 0;
tvin_plat = client->dev.platform_data;
if (tvin_plat->io_init)
tvin_plat->io_init();
if (tvin_plat->reset)
tvin_plat->reset();
if (tvin_plat->pwdn)
tvin_plat->pwdn(0);
msleep(1);
/* Set initial values for the sensor struct. */
memset(&adv7441a_data, 0, sizeof(adv7441a_data));
adv7441a_data.sen.i2c_client = client;
adv7441a_data.sen.streamcap.timeperframe.denominator = 30;
adv7441a_data.sen.streamcap.timeperframe.numerator = 1;
adv7441a_data.std_id = V4L2_STD_ALL;
video_idx = ADV7441A_NOT_LOCKED;
adv7441a_data.sen.streamcap.capability = V4L2_MODE_HIGHQUALITY | V4L2_CAP_TIMEPERFRAME;
adv7441a_data.sen.pix.width = video_fmts[video_idx].raw_width;
adv7441a_data.sen.pix.height = video_fmts[video_idx].raw_height;
adv7441a_data.sen.pix.pixelformat = V4L2_PIX_FMT_YUYV; //像素格式
adv7441a_data.sen.pix.priv = 1; /* 1 is used to indicate TV in */
adv7441a_data.sen.on = true;
adv7441a_data.sen.csi = 1;
}
4.7 V4L从设备给V4L主设备的获取时序模式参数的函数
static int ioctl_g_ifparm(struct v4l2_int_device *s, struct v4l2_ifparm *p)
{
if (s == NULL) {
pr_err(" ERROR!! no slave device set!\n");
return -1;
}
/* Initialize structure to 0s then set any non-0 values. */
memset(p, 0, sizeof(*p));
p->if_type = V4L2_IF_TYPE_BT1120;/* This is the only possibility. */
p->u.bt656.mode = V4L2_IF_TYPE_BT1120_MODE_BT_8BIT;
p->u.bt656.clock_curr = 1;
return 0;
}
4.8 V4L从设备给V4L主设备的获取分辨率的函数
static int ioctl_enum_framesizes(struct v4l2_int_device *s,
struct v4l2_frmsizeenum *fsize)
{
if (fsize->index >= 1)
return -EINVAL;
fsize->discrete.width = (hdmi_read(0x07) & 0x0f) * 256 + hdmi_read(0x08);
fsize->discrete.height = (hdmi_read(0x09) & 0x0f) * 256 + hdmi_read(0x0a);
adv7441a_autoset(fsize->discrete.width, fsize->discrete.height);
fsize->discrete.height -= (fsize->discrete.height) % 8;
return 0;
}
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