Huawei cloud 14 day Hongmeng device development -day5 drive subsystem development

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Preface

I learned before STM32 when , Have studied liteOS, Have a simple understanding of the kernel .

After learning the kernel , This time, learn some drive subsystems ,GPIO,I2C, A serial port ,ADC Data collection, etc . Mainly understand the encapsulated interface function and how to call .
Related concepts are stm32 I summarized it when I studied .
GPIO
ADC And DAC
I2C
A serial port
More can go to HAL Library column . This paper mainly summarizes Hongmeng's API Interface

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Chip pin diagram

First put a chip schematic , Easy to view pins

File structure chart

The following referenced header files are in the folder under this path bearpi-hm_nano/ base / iot_hardware

frameworks Inside the folder is c Source file , It is the implementation file of interface function ;hals Define header files for hardware abstraction layer functions in ; We mainly quote interfaces/kits The header file under , This folder provides a more convenient interface .

One 、GPIO

API Interface

The file path is base/iot_hardware/interfaces/kits/wifiiot_lite
stay wifiiot_gpio.h The statement is made. GPIO function , For initialization GPIO. Interrupt related functions are also declared .
stay wifiiot_gpio_ex.h The statement is made. GPIO spread function , Used for setting up GPIO Some properties of .
stay wifiiot_pwm.h The statement is made. PWM Related interface functions .

The interface name	Function description
GpioInit	initialization GPIO
GpioDeinit	Uninitialize GPIO
GpioSetDir	Set up GPIO Pin direction
GpioGetDir	obtain GPIO Pin direction
GpioSetOutputVal	Set up GPIO Pin output level value
GpioGetOutputVal	obtain GPIO Pin output level value
IoSetPull	Set up GPIO Pin pull-up
IoGetPull	obtain GPIO Pin pull-up
IoSetFunc	Set up GPIO Pin function
IoGetFunc	obtain GPIO Pin function
IoSetDriverStrength	Set up GPIO Driving ability
IoGetDriverStrength	obtain GPIO Driving ability

Find corresponding GPIO Pin
When we use the development board as the driver , You need to look at the circuit diagram to find the corresponding pin , Configure the code accordingly .

GPIO Basic case introduction

LedTask() by LED Main task of lamp test , This task calls GpioInit() initialization GPIO, because LED The control pin of the lamp is connected to GPIO_2 On , So by calling IoSetFunc() and GpioSetDir() take GPIO_2 Set to normal GPIO The output mode of . Finally, interval in the dead cycle 1s Output GPIO_2 High and low levels of , Realization LED The phenomenon of light flashing

static void LedTask(void)
{
    
    GpioInit();// initialization GPIO
    IoSetFunc(WIFI_IOT_IO_NAME_GPIO_2, WIFI_IOT_IO_FUNC_GPIO_2_GPIO);// Set up GPIO_2 The reuse function of is common GPIO
    GpioSetDir(WIFI_IOT_IO_NAME_GPIO_2, WIFI_IOT_GPIO_DIR_OUT);// Set up GPIO_2 For output mode 
    
    while (1) 
        {
    
            GpioSetOutputVal(WIFI_IOT_IO_NAME_GPIO_2, 1);// Set up GPIO_2 The output high level is on LED The lamp 
            usleep(1000000);// Time delay 1s
            GpioSetOutputVal(WIFI_IOT_IO_NAME_GPIO_2, 0);// Set up GPIO_2 The output low level is off LED The lamp 
            usleep(1000000);// Time delay 1s
        }
}

GPIO interrupt

The interface name	Function description
GpioRegisterIsrFunc	Set up GPIO Pin interrupt function
GpioUnregisterIsrFunc	Cancel GPIO Pin interrupt function
GpioSetIsrMask	shielding GPIO Pin interrupt function
GpioSetIsrMode	Set up GPIO Pin interrupt trigger mode

GPIO Introduction to interruption case

Through the key control LED The light is on and off . Here, press the key F1 For example , Key F1 The detection pin is connected with the main control chip GPIO_11 Connect , First by calling IoSetFunc() and GpioSetDir() take GPIO_11 Set to normal GPIO Input mode of . As can be seen from the previous schematic diagram , When the key is pressed ,GPIO_11 Will be pulled down to the ground , So we need to use IoSetPull() take GPIO_11 The pin is set to pull-up, i.e. high level , In this way, the level jump can be generated . Finally through GpioRegisterIsrFunc() Set the interrupt type to edge trigger , And it is triggered by the falling edge , When the key is pressed ,GPIO_11 Will change from high level to low level , Produce a drop , This will trigger the interrupt and call back F1_Pressed function . stay F1_Pressed Function LED Light operation .

static void F1_Pressed(char *arg)
{
    
    (void) arg;
    GpioSetOutputVal(WIFI_IOT_IO_NAME_GPIO_2, 1);
}
static void F2_Pressed(char *arg)
{
    
    (void) arg;
    GpioSetOutputVal(WIFI_IOT_IO_NAME_GPIO_2, 0);
}
static void ButtonExampleEntry(void)
{
    
    GpioInit();
    /***** initialization LED The lamp *****/
    IoSetFunc(WIFI_IOT_IO_NAME_GPIO_2, WIFI_IOT_IO_FUNC_GPIO_2_GPIO);
    GpioSetDir(WIFI_IOT_IO_NAME_GPIO_2, WIFI_IOT_GPIO_DIR_OUT);
    /***** initialization F1 Key , Set as falling edge trigger interrupt *****/
    IoSetFunc(WIFI_IOT_IO_NAME_GPIO_11, WIFI_IOT_IO_FUNC_GPIO_11_GPIO);
    GpioSetDir(WIFI_IOT_IO_NAME_GPIO_11, WIFI_IOT_GPIO_DIR_IN);
    IoSetPull(WIFI_IOT_IO_NAME_GPIO_11, WIFI_IOT_IO_PULL_UP);
    GpioRegisterIsrFunc(WIFI_IOT_IO_NAME_GPIO_11, WIFI_IOT_INT_TYPE_EDGE, WIFI_IOT_GPIO_EDGE_FALL_LEVEL_LOW,F1_Pressed, NULL);
    /***** initialization F2 Key , Set as falling edge trigger interrupt *****/
    IoSetFunc(WIFI_IOT_IO_NAME_GPIO_12, WIFI_IOT_IO_FUNC_GPIO_12_GPIO);
    GpioSetDir(WIFI_IOT_IO_NAME_GPIO_12, WIFI_IOT_GPIO_DIR_IN);
    IoSetPull(WIFI_IOT_IO_NAME_GPIO_12, WIFI_IOT_IO_PULL_UP);
    GpioRegisterIsrFunc(WIFI_IOT_IO_NAME_GPIO_12, WIFI_IOT_INT_TYPE_EDGE, WIFI_IOT_GPIO_EDGE_FALL_LEVEL_LOW,F2_Pressed, NULL);

}

PWM Output

The interface name	Function description
PwmInit	initialization PWM
PwmDeinit	Uninitialize PWM
PwmStart	Output according to input parameters PWM
PwmStop	stop it PWM Output

PWM Case introduction

This case will use onboard LED To verify GPIO Of PWM function , stay BearPi-HM_Nano Development board LED The connection circuit diagram of is shown in the basic part ,LED The control pin is connected with the main control chip GPIO_2 Connect , So you need to write software to control GPIO_2 Output PWM Wave to achieve the effect of breathing lamp . When the power is high, it is on , Low power usually goes out .
PWMTask() by PWM Test the main task , This task calls GpioInit() initialization GPIO, because LED The control pin of the lamp is connected to GPIO_2 On , So by calling IoSetFunc() take GPIO_2 Reuse as PWM function , And pass PwmInit() initialization PWM2 port , Finally, interval in the dead cycle 10us Output signals with different duty cycles PWM wave , To achieve the effect of breathing lamp .

static void PWMTask(void)
{
    
    unsigned int i;

    GpioInit();// initialization GPIO
    IoSetFunc(WIFI_IOT_IO_NAME_GPIO_2, WIFI_IOT_IO_FUNC_GPIO_2_PWM2_OUT);// Set up GPIO_2 The pin multiplexing function is PWM
    GpioSetDir(WIFI_IOT_IO_NAME_GPIO_2, WIFI_IOT_GPIO_DIR_OUT);// Set up GPIO_2 Pin is output mode 
    PwmInit(WIFI_IOT_PWM_PORT_PWM2);// initialization PWM2 port 

    while (1) 
        {
    
            for (i = 0; i < 40000; i += 100)
            {
    
                PwmStart(WIFI_IOT_PWM_PORT_PWM2, i, 40000); // Output signals with different duty cycles PWM wave 
                usleep(10);
            }            
            i = 0;
        }    
}

Two 、ADC sampling

ADC The principle of is summarized in the link of the preface is ok , You can check it out , Is to sample analog quantity , Convert to digital quantity .

API function

AdcRead()： From the specified... According to the input parameters ADC The channel reads a section of sampling data
unsigned int AdcRead (WifiIotAdcChannelIndex channel, unsigned short * data, WifiIotAdcEquModelSel equModel, WifiIotAdcCurBais curBais, unsigned short rstCnt )

Parameters	explain
channel	ADC passageway
data	Address pointer for storing read data
equModel	Represents the number of average algorithms
curBais	Indicates analog power control mode
rstCnt	Indicates the time count from reset to the beginning of the conversion

ADC Case introduction

This case will use onboard user buttons F1 To simulate the GPIO Change of port voltage . See the chip manual GPIO_11 The corresponding is ADC Channel 5 , So you need to write software to read ADC Channel 5 The voltage of , When programming, first GPIO_11 Pull up , send GPIO_11 The voltage of is always at a high level , When the key is pressed GPIO_11 Grounding , here GPIO_11 The voltage of becomes 0 V.

Software function design
This function uses AdcRead() Function to read ADC_CHANNEL_5 The value of is stored in data in , WIFI_IOT_ADC_EQU_MODEL_8 Express 8 Sub average algorithm mode ,WIFI_IOT_ADC_CUR_BAIS_DEFAULT Indicates the default automatic recognition mode , Finally through data * 1.8 * 4 / 4096.0 Calculate the actual voltage value .

static float GetVoltage(void)
{
    
    unsigned int ret;
    unsigned short data;

    ret = AdcRead(WIFI_IOT_ADC_CHANNEL_5, &data, WIFI_IOT_ADC_EQU_MODEL_8, WIFI_IOT_ADC_CUR_BAIS_DEFAULT, 0xff);
    if (ret != WIFI_IOT_SUCCESS) 
    {
    
        printf("ADC Read Fail\n");            
    }
    return (float)data * 1.8 * 4 / 4096.0;  /* data * 1.8 * 4 / 4096.0: Convert code into voltage */
}

After compiling and burning the sample code , Press... On the development board RESET Key , View the log through the serial port assistant , When F1 The voltage collected when the key is not pressed is 3.3V about , When the key is pressed , The voltage becomes 0.2V about .

3、 ... and 、I2C Reading and writing NFC chip

API

The interface name	Function description
I2cInit	initialization I2C
I2cDeinit	Uninitialize I2C
I2cWrite	Writes data to I2C equipment
I2cRead	Read data from the device
I2cWriteread	Composite communication , Send data to the device and receive the data response
I2cSetBaudrate	Set up I2C frequency

I2C Case introduction

NFC The chip uses I2C agreement ,I2C_SCL And GPIO_0 Connect ,I2C_SDA And GPIO_1 Connect , So you need to write software to use GPIO_0 and GPIO_1 produce I2C Signal to control NFC chip .

Software function design
I2C Initialized code , First use IoSetFunc() Function will GPIO_0 Reuse as I2C1_SDA,GPIO_1 Reuse as I2C1_SCL. And then call I2cInit() Function initialization I2C1 port , Finally using I2cSetBaudrate() Function settings I2C1 The frequency of is 400kbps.

IoSetFunc(WIFI_IOT_IO_NAME_GPIO_0, WIFI_IOT_IO_FUNC_GPIO_0_I2C1_SDA);   // GPIO_0 Reuse as I2C1_SDA
IoSetFunc(WIFI_IOT_IO_NAME_GPIO_1, WIFI_IOT_IO_FUNC_GPIO_1_I2C1_SCL);   // GPIO_1 Reuse as I2C1_SCL
I2cInit(WIFI_IOT_I2C_IDX_1, 400000); /* baudrate: 400kbps */
I2cSetBaudrate(WIFI_IOT_I2C_IDX_1, 400000);

towards NFC The chip writes data , But you need to write 2 When it's a record , The first 2 The location of a record needs to be NDEFLastPos To define ; When writing is required 3 When it's a record , The first 2 And the first 3 The location of each record needs to be NDEFMiddlePos and NDEFLastPos To define .

ret=storeText(NDEFFirstPos, (uint8_t *)TEXT);
if(ret != 1)
{
    
    printf("NFC Write Data Falied :%d ",ret);
}
ret=storeUrihttp(NDEFLastPos, (uint8_t *)WEB);
if(ret != 1)
{
    
    printf("NFC Write Data Falied :%d ",ret);
}

Four 、UART Reading and writing

API

UartInit()
unsigned int UartInit (WifiIotUartIdx id, const WifiIotUartAttribute * param, const WifiIotUartExtraAttr * extraAttr )

Parameters	explain
id	UART Port number
param	Represent basic UART attribute
extraAttr	Represents an extension UART attribute

UartWrite()
int UartWrite (WifiIotUartIdx id, const unsigned char * data, unsigned int dataLen )

UartRead()
int UartRead (WifiIotUartIdx id, unsigned char * data, unsigned int dataLen )

Parameters	explain
id	UART Port number .
data	A pointer to the starting address of the data to be read and written
dataLen	Represents the length of the data

UART Case introduction

This case will use BearPi-HM_Nano Development board E53 Interface UART As a test , As shown in the schematic diagram, section 18 and 19 The feet are TXD and RXD , Connected to the main control chip GPIO_6 and GPIO_5 , So when writing software, you need to GPIO_6 and GPIO_5 Reuse as TXD and RXD .

Software function design
UART Initialized code , In the first uart_attr This structure configures the baud rate 、 Data bits 、 Stop bit 、 Parity check bit , And then through UartInit() Function to serial port 1 To configure .

WifiIotUartAttribute uart_attr = {
    
    .baudRate = 9600, /* baud_rate: 9600 */
    .dataBits = 8,      /* data_bits: 8bits */
    .stopBits = 1,
    .parity = 0,
};

/* Initialize uart driver */
ret = UartInit(WIFI_IOT_UART_IDX_1, &uart_attr, NULL);
if (ret != WIFI_IOT_SUCCESS) {
    
    printf("Failed to init uart! Err code = %d\n", ret);
    return;
}

adopt UartWrite() Function in serial port 1 Send a string of data , And then through UartRead() Function returns all the data , And pass debug Serial port print out .

UartWrite(WIFI_IOT_UART_IDX_1, (unsigned char *)data, strlen(data));    //  Through serial port 1 send data 
UartRead(WIFI_IOT_UART_IDX_1,uart_buff_ptr,UART_BUFF_SIZE);             //  Through serial port 1 receive data 
printf("%s",uart_buff_ptr);

summary

The course is very simple , It's how to use it , The principles still need to be learned .