作者： TI 工程師 Wesley He

在一些特殊的使用場合，有需要使用AWR1642對PMIC的輸出電壓進行調節，或是讀取PMIC 內部的工作狀態，此時需要I2C接口對PMIC進行讀寫操作，本文介紹了在現有的mmWave SDK demo中集成I2C接口驅動所需的步驟及操作。

本文的測試環境如下：

測試軟件版本：mmWave SDK 2.0.0.4

測試硬件：AWR1642BOOST EVM

1. 在mmWave SDK demo中增加I2C驅動代碼

第一步是添加代碼以包含和初始化I2C驅動程序。從I2C接口發送和接收均需要此驅動程序的支持，以下是在mss_main.c中添加的初始化I2C驅動程序的C代碼。此測試代碼可以復制到現有工程中。I2C驅動操作步驟為：GPIO初始化，I2C驅動初始化，配置I2C改寫PMIC(LP87524B)寄存器以實現PMIC輸出電壓調節。

注意LP87524B寄存器信息來源于其datasheet：LP87524B/J-Q1具有集成開關的具有集成開關的 4-A + 2.5-A +兩個 1.5-A降壓穩壓器數據表 (Rev. A)，I2C驅動參考代碼如下：

#include

static int32_t I2C_GPIOInit(void)

{

#if (defined(SOC_XWR14XX))

/* Setup the PINMUX to bring out the XWR14xx I2C pins */

Pinmux_Set_OverrideCtrl(SOC_XWR14XX_PINR3_PADAH, PINMUX_OUTEN_RETAIN_HW_CTRL, PINMUX_INPEN_RETAIN_HW_CTRL);

Pinmux_Set_FuncSel(SOC_XWR14XX_PINR3_PADAH, SOC_XWR14XX_PINR3_PADAH_I2C_SDA);

Pinmux_Set_OverrideCtrl(SOC_XWR14XX_PINP4_PADAI, PINMUX_OUTEN_RETAIN_HW_CTRL, PINMUX_INPEN_RETAIN_HW_CTRL);

Pinmux_Set_FuncSel(SOC_XWR14XX_PINP4_PADAI, SOC_XWR14XX_PINP4_PADAI_I2C_SCL);

#else

/* Setup the PINMUX to bring out the XWR16xx I2C pins */

Pinmux_Set_OverrideCtrl(SOC_XWR16XX_PINF13_PADAH, PINMUX_OUTEN_RETAIN_HW_CTRL, PINMUX_INPEN_RETAIN_HW_CTRL);

Pinmux_Set_FuncSel(SOC_XWR16XX_PINF13_PADAH, SOC_XWR16XX_PINF13_PADAH_I2C_SDA);

Pinmux_Set_OverrideCtrl(SOC_XWR16XX_PING14_PADAI, PINMUX_OUTEN_RETAIN_HW_CTRL, PINMUX_INPEN_RETAIN_HW_CTRL);

Pinmux_Set_FuncSel(SOC_XWR16XX_PING14_PADAI, SOC_XWR16XX_PING14_PADAI_I2C_SCL);

#endif

return 0;

}

static int32_t I2C_Communication_Test()

{

bool retVal = false;

int32_t errCode = 0;

uint32_t arg;

uint8_t rxData[16];

uint8_t txData[16];

I2C_Transaction i2cTransaction;

I2C_Handle i2cHandle;

I2C_Params i2cParams;

/* Reset the transmit and receive buffer */

memset(&rxData, 0, sizeof (rxData));

/* Initializa the I2C driver */

I2C_init();

/* Initialize the I2C driver default parameters */

I2C_Params_init(&i2cParams);

i2cParams.transferMode = I2C_MODE_BLOCKING;

i2cParams.bitRate = I2C_100kHz;

/* Open the I2C driver */

i2cHandle = I2C_open(0, &i2cParams);

if (i2cHandle == NULL)

{

System_printf ("Error: I2C Driver Open failed\n");

return -1;

}

/* Configure the I2C device in I2C_CMD_ADDR_MODE mode */

arg = 0;//arg set to 0, and the I2C addr mode is 7-bit.

errCode = I2C_control (i2cHandle, I2C_CMD_ADDR_MODE, (void* )&arg);

if (errCode < 0)

{

System_printf ("Error: I2C control Set I2C_CMD_ADDR_MODE failed [Error code %d]\n", errCode);

return -1;

}

//read the LP87524B buck3 output voltage register

txData[0] = 0x10;

i2cTransaction.slaveAddress = 0x60;//LP87524B/J-Q1 Device Address = 0x60

i2cTransaction.writeBuf = txData;

i2cTransaction.writeCount = 1;

i2cTransaction.readBuf = rxData;

i2cTransaction.readCount = 1;

retVal = I2C_transfer(i2cHandle, &i2cTransaction);

if (retVal == false)

{

System_printf ("Error: I2C Transfer failed\n");

return -1;

}

System_printf("I2C_READ: addr=0x%x, Val=0x%x\n",txData[0],rxData[0]);

//write the LP87524B buck3 output voltage = 2.0V

txData[0] = 0x10;

txData[1] = 0xbb;//default=0xca,2.3V,0xb1=1.8V, 0xbb=2.0V

i2cTransaction.slaveAddress = 0x60;//LP87524B/J-Q1 Device Address = 0x60

i2cTransaction.writeBuf = txData;

i2cTransaction.writeCount = 2;

i2cTransaction.readBuf = rxData;

i2cTransaction.readCount = 0;

retVal = I2C_transfer(i2cHandle, &i2cTransaction);

if (retVal == false)

{

System_printf ("Error: I2C Transfer failed\n");

return -1;

}

System_printf("I2C_Write: LP87524B buck3 = 2.0V Done\n");

//read the LP87524B buck3 output voltage register

txData[0] = 0x10;

i2cTransaction.slaveAddress = 0x60;//LP87524B/J-Q1 Device Address = 0x60

i2cTransaction.writeBuf = txData;

i2cTransaction.writeCount = 1;

i2cTransaction.readBuf = rxData;

i2cTransaction.readCount = 1;

retVal = I2C_transfer(i2cHandle, &i2cTransaction);

if (retVal == false)

{

System_printf ("Error: I2C Transfer failed\n");

return -1;

}

System_printf("I2C_READ: addr=0x%x, Val=0x%x\r\n",txData[0],rxData[0]);

//write the LP87524B buck2 output voltage = 1.5V

txData[0] = 0x0e;

txData[1] = 0Xa2;//default=0xb1,1.8V, 0x4d=1V 0xa2=1.5V

i2cTransaction.slaveAddress = 0x60;//LP87524B/J-Q1 Device Address = 0x60

i2cTransaction.writeBuf = txData;

i2cTransaction.writeCount = 2;

i2cTransaction.readBuf = rxData;

i2cTransaction.readCount = 0;

retVal = I2C_transfer(i2cHandle, &i2cTransaction);

if (retVal == false)

{

System_printf ("Error: I2C Transfer failed\n");

return -1;

}

System_printf("I2C_Write: LP87524B buck2 = 1.5V Done\n");

if (retVal == false)

{

System_printf ("Error: I2C combined Transfer to Slave failed\n");

return -1;

}

/* Close I2C driver */

I2C_close(i2cHandle);

return 0;

}

//Call these function in void MmwDemo_mssInitTask(UArg arg0, UArg arg1)

errCode = I2C_GPIOInit();

if (errCode == -1)

System_printf("I2C_GPIOInit Error\r\n");

errCode = I2C_Communication_Test();

if (errCode == -1)

System_printf("I2C_Communication_Test Error\n");

else

System_printf("I2C_Communication_Test Done\n");

2. 將工程鏈接到I2C驅動庫

最后一步是通過鏈接I2C驅動程序來構建可執行文件。 如果使用CCS項目，可以將I2C驅動程序添加到項目的鏈接器屬性中，如圖1所示。

圖1. CCS Project Linker Properties

如果使用makefile編譯工程，執行相同的程序。

###################################################################################

# Additional libraries which are required to build the DEMO:

###################################################################################

MSS_MMW_DEMO_STD_LIBS = $(R4F_COMMON_STD_LIB) \

-llibpinmux_$(MMWAVE_SDK_DEVICE_TYPE).$(R4F_LIB_EXT) \

-llibdma_$(MMWAVE_SDK_DEVICE_TYPE).$(R4F_LIB_EXT) \

-llibcrc_$(MMWAVE_SDK_DEVICE_TYPE).$(R4F_LIB_EXT) \

-llibuart_$(MMWAVE_SDK_DEVICE_TYPE).$(R4F_LIB_EXT) \

-llibgpio_$(MMWAVE_SDK_DEVICE_TYPE).$(R4F_LIB_EXT) \

-llibmailbox_$(MMWAVE_SDK_DEVICE_TYPE).$(R4F_LIB_EXT) \

-llibmmwavelink_$(MMWAVE_SDK_DEVICE_TYPE).$(R4F_LIB_EXT) \

-llibmmwave_$(MMWAVE_SDK_DEVICE_TYPE).$(R4F_LIB_EXT) \

-llibcli_$(MMWAVE_SDK_DEVICE_TYPE).$(R4F_LIB_EXT) \

-llibi2c_$(MMWAVE_SDK_DEVICE_TYPE).$(R4F_LIB_EXT)

MSS_MMW_DEMO_LOC_LIBS = $(R4F_COMMON_LOC_LIB) \

-i$(MMWAVE_SDK_INSTALL_PATH)/ti/drivers/pinmux/lib \

-i$(MMWAVE_SDK_INSTALL_PATH)/ti/drivers/uart/lib \

-i$(MMWAVE_SDK_INSTALL_PATH)/ti/drivers/dma/lib \

-i$(MMWAVE_SDK_INSTALL_PATH)/ti/drivers/crc/lib \

-i$(MMWAVE_SDK_INSTALL_PATH)/ti/drivers/gpio/lib \

-i$(MMWAVE_SDK_INSTALL_PATH)/ti/drivers/mailbox/lib \

-i$(MMWAVE_SDK_INSTALL_PATH)/ti/control/mmwavelink/lib \

-i$(MMWAVE_SDK_INSTALL_PATH)/ti/control/mmwave/lib \

-i$(MMWAVE_SDK_INSTALL_PATH)/ti/utils/cli/lib \

-i$(MMWAVE_SDK_INSTALL_PATH)/ti/utils/i2c/lib

3. 運行測試例程

運行測試程序后，CCS控制臺輸出打印信息如下，使用萬用表測量LP87524輸出電壓即為設置的電壓，I2C驅動添加成功。

**********************************************

Debug: Launching the Millimeter Wave Demo

**********************************************

I2C_READ: addr=0x10, Val=0xca

I2C_Write: LP87524B buck3 = 2.0V Done

I2C_READ: addr=0x10, Val=0xbb

I2C_Write: LP87524B buck2 = 1.5V Done

I2C_Communication_Test Done

審核編輯：何安