EMIO方式模拟I2C时序对ADV7511进行读写

创建硬件工程，很简单，PS接出两个EMIO和一个74.25M时钟

管脚约束
# ADV7511 I2C_SCL
set_property PACKAGE_PIN AA18 [get_ports {gpio_0_tri_io[0]}]
set_property IOSTANDARD LVCMOS33 [get_ports {gpio_0_tri_io[0]}]

# ADV7511 I2C_SDA
set_property PACKAGE_PIN Y16 [get_ports {gpio_0_tri_io[1]}]
set_property IOSTANDARD LVCMOS33 [get_ports {gpio_0_tri_io[1]}]

# ADV7511 HDMI_CLK
set_property PACKAGE_PIN W18 [get_ports {FCLK_CLK1}]
set_property IOSTANDARD LVCMOS33 [get_ports {FCLK_CLK1}]

导出 Hardware，启动SDK，新建一个应用，添加以下代码

EMIO_init.c
#include "EMIO_init.h"

static XGpioPs psGpioInstancePtr;
int EMIO_I2C_init(void)
{
XGpioPs_Config* GpioConfigPtr;
int xStatus;

GpioConfigPtr = XGpioPs_LookupConfig(XPAR_PS7_GPIO_0_DEVICE_ID);
if(GpioConfigPtr == NULL)
return XST_FAILURE;

xStatus = XGpioPs_CfgInitialize(&psGpioInstancePtr,GpioConfigPtr,GpioConfigPtr->BaseAddr);
if(XST_SUCCESS != xStatus)
print("EMIO INIT FAILED ");

XGpioPs_SetDirectionPin(&psGpioInstancePtr, SIOC_PIN,DIRECTION_OUTPUT);
XGpioPs_SetDirectionPin(&psGpioInstancePtr, SIOD_PIN,DIRECTION_OUTPUT);

XGpioPs_SetOutputEnablePin(&psGpioInstancePtr, SIOC_PIN,1);
XGpioPs_SetOutputEnablePin(&psGpioInstancePtr, SIOD_PIN,1);

return xStatus;
}

void CLOCK_HIGH(void)
{
XGpioPs_WritePin(&psGpioInstancePtr,SIOC_PIN, 1);
}

void CLOCK_LOW(void)
{
XGpioPs_WritePin(&psGpioInstancePtr,SIOC_PIN, 0);
}

int GET_DATA(void)
{
return XGpioPs_ReadPin(&psGpioInstancePtr,SIOD_PIN);
}

void DATA_INPUT(void)
{
XGpioPs_SetDirectionPin(&psGpioInstancePtr, SIOD_PIN,DIRECTION_INPUT);//
}

void DATA_OUTPUT(void)
{
XGpioPs_SetDirectionPin(&psGpioInstancePtr, SIOD_PIN,DIRECTION_OUTPUT);//
}

void DATA_HIGH(void)
{
XGpioPs_WritePin(&psGpioInstancePtr,SIOD_PIN, 1);
}

void DATA_LOW(void)
{
XGpioPs_WritePin(&psGpioInstancePtr,SIOD_PIN,0);
}

EMIO_init.h
#ifndef EMIO_INIT_H_
#define EMIO_INIT_H_

#include "xgpiops.h"

int EMIO_I2C_init(void);

#define SIOC_PIN 54
#define SIOD_PIN 55
#define RESET_PIN 56

#define DIRECTION_INPUT 0
#define DIRECTION_OUTPUT 1

void CLOCK_HIGH(void);

void CLOCK_LOW(void);

void DATA_HIGH(void);

void DATA_LOW(void);

void DATA_INPUT(void);

void DATA_OUTPUT(void);

int GET_DATA(void);

#endif /* EMIO_INIT_H_ */

I2C_ctrl.c
#include "sleep.h"
#include "EMIO_init.h"

#define I2C_DELAY usleep(10)

void I2C_start(void)
{
CLOCK_HIGH();
DATA_HIGH();
I2C_DELAY;
DATA_LOW();
I2C_DELAY;
CLOCK_LOW();
I2C_DELAY;
}

void I2C_end(void)
{
DATA_LOW();
I2C_DELAY;
CLOCK_HIGH();
I2C_DELAY;
DATA_HIGH();
I2C_DELAY;
}

int I2C_sendbyte( unsigned char value )
{
unsigned char tmp = value;
unsigned char i=0,ack;

for(i=0; i<8; i++)
{
if(tmp & 0x80 )
DATA_HIGH();
else
DATA_LOW();

I2C_DELAY;
CLOCK_HIGH();
I2C_DELAY;
CLOCK_LOW();
I2C_DELAY;

tmp<<=1;
}

DATA_HIGH();
DATA_INPUT();
I2C_DELAY;
CLOCK_HIGH();
ack = GET_DATA();
I2C_DELAY;
CLOCK_LOW();
I2C_DELAY;
DATA_OUTPUT();

if(ack==1)
{
return -1;
}

return 0;
}

unsigned char I2C_readbyte( unsigned char addr)
{
unsigned char i=0,data=0;

DATA_HIGH();
DATA_INPUT();

for(i=0; i<8; i++)
{
CLOCK_HIGH();
I2C_DELAY;

data <<= 1;
if(GET_DATA())
data |= 1;

I2C_DELAY;
CLOCK_LOW();
I2C_DELAY;
}

DATA_OUTPUT();
DATA_HIGH();
I2C_DELAY;
CLOCK_HIGH();
I2C_DELAY;
CLOCK_LOW();
I2C_DELAY;
DATA_HIGH();

return data;
}

int I2C_readdata(unsigned char id, unsigned char addr, unsigned char *value)
{
// 两相写
I2C_start();
if(I2C_sendbyte(id<<1) != 0)
{
goto error;
}

if(I2C_sendbyte(addr) != 0)
{
goto error;
}

// 两相读
I2C_start();
if(I2C_sendbyte((id<<1)|0x1) != 0)
{
goto error;
}
*value = I2C_readbyte(addr);
I2C_end();

return 0;

error:
I2C_end();
return -1;
}