[原创] 【基于KW41Z的智能电力监测仪的设计】第五贴：软件设计—GPIO学习篇

传媒学子 2017-7-11 00:20 楼主

【基于KW41Z的智能电力监测仪的设计】第五贴：软件设计—GPIO学习篇

0 .题外话

借参加NXP设计大赛的机会，想一窥嵌入式编程的大门。以前，学习总是不踏实，好高骛远。虽然，玩过很多单片机，但总是不能学到器件的精髓。虽然英语也看得懂，但总是很懒。这次正好在毕业到入职之间有1个月的空闲时间，与其出去瞎转，倒不如认真学习学习嵌入式编程之道。认真从恩智浦这款优秀的微处理器上，得以领略到高层次编程的乐趣。

因为，之前学习过51之类的，都是从底层寄存器级开始编程，自己看着芯片手册写相关模块的程序，虽然很费时间，但毕竟习惯了那种学习方法，因此，刚刚接触到例程中的高层次的编程，则十分并不习惯。通过一下午的学习，基本上明白了NXP官方给的GPIO API库的使用方法，并且将原始程序进行了简单修改，实现了LED3和RGB（GREEN）的轮番点亮。

1. 首先介绍官方的例程效果

官方例程，按下SW3，进入中断，RGB（RED）实现亮灭转换。

2. 遇到的困难

本想修改一下例程，让RGB（GREEN）点亮，但尝试了几次，没有想象中的容易，因此，就硬下心来，将例程一点一点的吃透。

3.我想把感悟分享给初学者：

感悟1：学习一款板子，必须要把这个板子的基本构造，原理图等熟悉一遍，我这里把FFRDM-KW41Z Freedom Development BoardUser's Guide分享给大家，见附件。看完了手册，我们知道了RGB是由三个LED组成的：RED\GREEN\BLUE,它们分别位PTC1\PTA19\PTA18；而另外一个LED3是红色LED，它位于PTB0。知道了具体的连接，再看例程，就能举一反三，触类旁通。

感悟2：注意到source目录下gpio_input_interrupt.c是整个工程的主函数所在。打开后，可看到与GPIO相关的定义都与Board有关，因此，很容易使人想起去改写"board.h"文件，但我依葫芦画瓢改写后，依然不能点亮LED3，这时应当注意到还有一个BOARD_InitPins(void)函数，打开这个函数则一目了然。其原因是：我没有注意BOARD_InitPins()函数内容，GPIO 未使能。

改写主程序：

#include "fsl_debug_console.h"[/align]#include "fsl_port.h"
#include "fsl_gpio.h"
#include "fsl_common.h"
#include "board.h"
#include "pin_mux.h"
#include "clock_config.h"
/*******************************************************************************
* Definitions
******************************************************************************/
//#define BOARD_LED_GPIO BOARD_LED_RED_GPIO
//#define BOARD_LED_GPIO_PIN BOARD_LED_RED_GPIO_PIN
#define BOARD_LED_GPIO BOARD_LED_GREEN_GPIO
#define BOARD_LED_GPIO_PIN BOARD_LED_GREEN_GPIO_PIN
#define BOARD_SW_GPIO BOARD_SW3_GPIO
#define BOARD_SW_PORT BOARD_SW3_PORT
#define BOARD_SW_GPIO_PIN BOARD_SW3_GPIO_PIN
#define BOARD_SW_IRQ BOARD_SW3_IRQ
#define BOARD_SW_IRQ_HANDLER BOARD_SW3_IRQ_HANDLER
#define BOARD_SW_NAME BOARD_SW3_NAME
/*******************************************************************************
* Prototypes
******************************************************************************/
/*******************************************************************************
* Variables
******************************************************************************/
/* Whether the SW button is pressed */
volatile bool g_ButtonPress = false;
/*******************************************************************************
* Code
******************************************************************************/
/*!
* [url=home.php?mod=space&uid=159083]@brief[/url] Interrupt service fuction of switch. 中断服务函数
*
* This function toggles the LED
*/
void BOARD_SW_IRQ_HANDLER(void)
{
/* Clear external interrupt flag. */
GPIO_ClearPinsInterruptFlags(BOARD_SW_GPIO, 1U << BOARD_SW_GPIO_PIN);//1右移四位0x10
/* Change state of button. */
g_ButtonPress = true;
/* Toggle LED. */
GPIO_TogglePinsOutput(BOARD_LED_GPIO, 1U << BOARD_LED_GPIO_PIN);
GPIO_TogglePinsOutput(BOARD_LED3_GPIO, 1U << BOARD_LED3_GPIO_PIN);
}
/*!
* @brief Main function
*/
int main(void)
{
/* Define the init structure for the input switch pin */
gpio_pin_config_t sw_config = {
kGPIO_DigitalInput, 0,
};
/* Define the init structure for the output LED pin */
gpio_pin_config_t led_config = {
kGPIO_DigitalOutput, 0,
}; //配置结构体设置输入，输出（输入/输出，输出1或者0），当在输入状态下，输出没有效果
gpio_pin_config_t led3_config = {
kGPIO_DigitalOutput, 1,
};
BOARD_InitPins();
BOARD_BootClockRUN();
BOARD_InitDebugConsole();
/* Print a note to terminal. */
PRINTF("\r\n GPIO Driver example\r\n");
PRINTF("\r\n Press %s to turn on/off a LED \r\n", BOARD_SW_NAME);
/* Init input switch GPIO. */
PORT_SetPinInterruptConfig(BOARD_SW_PORT, BOARD_SW_GPIO_PIN, kPORT_InterruptFallingEdge);
EnableIRQ(BOARD_SW_IRQ);
GPIO_PinInit(BOARD_SW_GPIO, BOARD_SW_GPIO_PIN, &sw_config);
/* Init output LED GPIO. */
GPIO_PinInit(BOARD_LED_GPIO, BOARD_LED_GPIO_PIN, &led_config);
//以下为修改部分
GPIO_PinInit(BOARD_LED3_GPIO, BOARD_LED3_GPIO_PIN, &led3_config);
//////////////////以上为修改部分/////////////////
while (1)
{
if (g_ButtonPress)
{
PRINTF(" %s is pressed \r\n", BOARD_SW_NAME);
/* Reset state of button. */
g_ButtonPress = false;
}
}
}

改写board.h文件：

#ifndef _BOARD_H_
#define _BOARD_H_
#include "clock_config.h"
#include "fsl_gpio.h"
/*******************************************************************************
* Definitions
******************************************************************************/
/*! @brief The board name */
#define BOARD_NAME "FRDM-KW41Z"
/*! @brief The UART to use for debug messages. */
#define BOARD_USE_LPUART
#define BOARD_DEBUG_UART_TYPE DEBUG_CONSOLE_DEVICE_TYPE_LPUART
#define BOARD_DEBUG_UART_BASEADDR (uint32_t) LPUART0
#define BOARD_DEBUG_UART_CLKSRC kCLOCK_Osc0ErClk
#define BOARD_DEBUG_UART_CLK_FREQ CLOCK_GetOsc0ErClkFreq()
#define BOARD_UART_IRQ LPUART0_IRQn
#define BOARD_UART_IRQ_HANDLER LPUART0_IRQHandler
#ifndef BOARD_DEBUG_UART_BAUDRATE
#define BOARD_DEBUG_UART_BAUDRATE 115200
#endif /* BOARD_DEBUG_UART_BAUDRATE */
/*! @brief The adc16 alternate reference voltage pin is used for frdmkw41 board rev A2 */
#define BOARD_ADC_USE_ALT_VREF 1U
/*! @brief The i2c instance used for i2c connection by default */
#define BOARD_I2C_BASEADDR I2C1
/*! @brief TSI electrodes mapping */
#define BOARD_TSI_ELECTRODE_1 4U
#define BOARD_TSI_ELECTRODE_2 7U
#define BOARD_TSI_ELECTRODE_CNT 2U
#define BOARD_ACCEL_I2C_BASEADDR I2C1
/*! @brief The CMP instance/channel used for board. */
#define BOARD_CMP_BASEADDR CMP0
#define BOARD_CMP_CHANNEL 1U
/*! @brief The rtc instance used for board. */
#define BOARD_RTC_FUNC_BASEADDR RTC
/*! @brief Define the port interrupt number for the board switches */
#define BOARD_SW3_GPIO GPIOC
#define BOARD_SW3_PORT PORTC
#define BOARD_SW3_GPIO_PIN 4U
#define BOARD_SW3_IRQ PORTB_PORTC_IRQn
#define BOARD_SW3_IRQ_HANDLER PORTB_PORTC_IRQHandler
#define BOARD_SW3_NAME "SW3"
/* Board led color mapping */
#define LOGIC_LED_ON 0U
#define LOGIC_LED_OFF 1U
#define BOARD_LED_RED_GPIO GPIOC
#define BOARD_LED_RED_GPIO_PORT PORTC
#define BOARD_LED_RED_GPIO_PIN 1U
#define BOARD_LED_GREEN_GPIO GPIOA
#define BOARD_LED_GREEN_GPIO_PORT PORTA
#define BOARD_LED_GREEN_GPIO_PIN 19U
#define BOARD_LED_BLUE_GPIO GPIOA
#define BOARD_LED_BLUE_GPIO_PORT PORTA
#define BOARD_LED_BLUE_GPIO_PIN 18U
//以下为个人改写部分
#define BOARD_LED3_GPIO GPIOB
#define BOARD_LED3_GPIO_PORT PORTB
#define BOARD_LED3_GPIO_PIN 0U
/*#define LED3_INIT(output) \
GPIO_PinInit(BOARD_LED3_GPIO, BOARD_LED3_GPIO_PIN, \
&(gpio_pin_config_t){kGPIO_DigitalOutput, (output)}) /*!< Enable target LED3 */
/*#define LED3_ON() \
GPIO_ClearPinsOutput(BOARD_LED3_GPIO, 1U << BOARD_LED3_GPIO_PIN) /*!< Turn on target LED3 */
/*#define LED3_OFF() \
GPIO_SetPinsOutput(BOARD_LED3_GPIO, 1U << BOARD_LED3_GPIO_PIN) /*!< Turn off target LED3 */
/*#define LED3_TOGGLE() \
GPIO_TogglePinsOutput(BOARD_LED3_GPIO, 1U << BOARD_LED3_GPIO_PIN) /*!< Toggle on target LED3 */
#define LED_RED_INIT(output) \
GPIO_PinInit(BOARD_LED_RED_GPIO, BOARD_LED_RED_GPIO_PIN, \
&(gpio_pin_config_t){kGPIO_DigitalOutput, (output)}) /*!< Enable target LED_RED */
#define LED_RED_ON() \
GPIO_ClearPinsOutput(BOARD_LED_RED_GPIO, 1U << BOARD_LED_RED_GPIO_PIN) /*!< Turn on target LED_RED */
#define LED_RED_OFF() \
GPIO_SetPinsOutput(BOARD_LED_RED_GPIO, 1U << BOARD_LED_RED_GPIO_PIN) /*!< Turn off target LED_RED */
#define LED_RED_TOGGLE() \
GPIO_TogglePinsOutput(BOARD_LED_RED_GPIO, 1U << BOARD_LED_RED_GPIO_PIN) /*!< Toggle on target LED_RED */
#define LED_GREEN_INIT(output) \
GPIO_PinInit(BOARD_LED_GREEN_GPIO, BOARD_LED_GREEN_GPIO_PIN, \
&(gpio_pin_config_t){kGPIO_DigitalOutput, (output)}) /*!< Enable target LED_GREEN */
#define LED_GREEN_ON() \
GPIO_ClearPinsOutput(BOARD_LED_GREEN_GPIO, 1U << BOARD_LED_GREEN_GPIO_PIN) /*!< Turn on target LED_GREEN */
#define LED_GREEN_OFF() \
GPIO_SetPinsOutput(BOARD_LED_GREEN_GPIO, 1U << BOARD_LED_GREEN_GPIO_PIN) /*!< Turn off target LED_GREEN */
#define LED_GREEN_TOGGLE() \
GPIO_TogglePinsOutput(BOARD_LED_GREEN_GPIO, 1U << BOARD_LED_GREEN_GPIO_PIN) /*!< Toggle on target LED_GREEN */
#define LED_BLUE_INIT(output) \
GPIO_PinInit(BOARD_LED_BLUE_GPIO, BOARD_LED_BLUE_GPIO_PIN, \
&(gpio_pin_config_t){kGPIO_DigitalOutput, (output)}) /*!< Enable target LED_BLUE */
#define LED_BLUE_ON() \
GPIO_ClearPinsOutput(BOARD_LED_BLUE_GPIO, 1U << BOARD_LED_BLUE_GPIO_PIN) /*!< Turn on target LED_BLUE */
#define LED_BLUE_OFF() \
GPIO_SetPinsOutput(BOARD_LED_BLUE_GPIO, 1U << BOARD_LED_BLUE_GPIO_PIN) /*!< Turn off target LED_BLUE */
#define LED_BLUE_TOGGLE() \
GPIO_TogglePinsOutput(BOARD_LED_BLUE_GPIO, 1U << BOARD_LED_BLUE_GPIO_PIN) /*!< Toggle on target LED_BLUE */
#if defined(__cplusplus)
extern "C" {
#endif /* __cplusplus */
/*******************************************************************************
* API
******************************************************************************/

改写 BOARD_InitPins(void)：

#include "fsl_common.h"
#include "fsl_port.h"
#include "pin_mux.h"
/*******************************************************************************
* Code
******************************************************************************/
void BOARD_InitPins(void)
{
/* Initialize LPUART0 pins below */
/* Ungate the port clock */
CLOCK_EnableClock(kCLOCK_PortC);
CLOCK_EnableClock(kCLOCK_PortA);
CLOCK_EnableClock(kCLOCK_PortB);
/* Affects PORTC_PCR6 register */
PORT_SetPinMux(PORTC, 6U, kPORT_MuxAlt4);
/* Affects PORTC_PCR7 register */
PORT_SetPinMux(PORTC, 7U, kPORT_MuxAlt4);
/* Affects PORTC_PCR4 register */
port_pin_config_t config;
config.pullSelect = kPORT_PullUp;
config.mux = kPORT_MuxAsGpio;
PORT_SetPinConfig(PORTC, 4U, &config); //PTC4设置为上拉
/* LED PIN_MUX Configuration */
PORT_SetPinMux(PORTC, 1U, kPORT_MuxAsGpio);
PORT_SetPinMux(PORTA, 19U, kPORT_MuxAsGpio);
PORT_SetPinMux(PORTB, 0U, kPORT_MuxAsGpio);
}