很荣幸在21IC论坛活动中获得一块MSP432P401R LanchPad。拿到开发板后，先搭建开发环境，MSP432P401R可在CCS、KEIL、IAR 3个IDE平台都可开发，这里选择了比较熟悉的KEIL。并对MSP432P401R的SDK进行熟悉。
刚好手头有一块带6轴LSM6DSO传感器的板子和一块0.96寸的OLED屏，两个都可通过I2C进行通讯。LSM6DSO传感器自带计步功能，既通过中断通知计步事件，也可以通过读取对应的寄存器获得。那就做一个计步功能，来测试MSP432P401R的I2C功能。
下图是I2C的框架图
MSP432P401R的I2C模块包括下列功能：
7位和10位设备寻址模式
启动、重启和停止
多主发射机/接收机模式
从接收机/发射机模式
支持高达100 Kbps的标准模式、高达400 Kbps的快速模式和高达1 Mbps的快速模式
主模式下可编程UCXCLK频率
专为低功耗设计
具有中断能力和自动停止断言的8位字节计数器
多达四个硬件从地址，每个都有自己的中断和DMA触发器
从机地址和地址接收中断的屏蔽寄存器
时钟低超时中断，以避免总线暂停
I2C模块的功能非常丰富。此次评测只使用I2C的基本功能。
硬件连接为SCL -- P1.7，SDA -- P1.6，gpio中断 -- P5.0。
/* DriverLib Includes */
#include <ti/devices/msp432p4xx/driverlib/driverlib.h>
/* Standard Includes */
#include <stdint.h>
#include <stdbool.h>
#include "i2c_driver.h"
#include "oled_i2c.h"
#include "Lsm6dso.h"
#define system_jump_time 1000 // 1/system_jump_time = 1ms
/* Slave Address for I2C Slave */
#define SLAVE_ADDRESS_1 0x48
#define SLAVE_ADDRESS_2 0x49
#define NUM_OF_REC_BYTES 10
#define I2C_DELAY 50
uint32_t i, j;
uint32_t pedometerCnt, pedometerCntOld = 0xffffffff;
static uint8_t index, indexOld = 0xff;
//一次滴答中断的tick数
uint32_t System_tick_num;
static uint32_t delayCnt = 0xffffffff, delayTarget = 0;
static uint8_t delayFinFlag = 0;
static volatile uint8_t Lsm6dsoEventDetected = 0;
uint8_t pedoFlag = 0;
//
void pedometerShow(void);
void MCU_Init()
{
// Set P1.0 to output direction
GPIO_setAsOutputPin(GPIO_PORT_P1, GPIO_PIN0);
/* Configuring P1.1 as an input and enabling interrupts */
MAP_GPIO_setAsInputPinWithPullUpResistor(GPIO_PORT_P1, GPIO_PIN1);
MAP_GPIO_clearInterruptFlag(GPIO_PORT_P1, GPIO_PIN1);
MAP_GPIO_enableInterrupt(GPIO_PORT_P1, GPIO_PIN1);
MAP_Interrupt_enableInterrupt(INT_PORT1);
/* Configuring P1.1 as an input and enabling interrupts */
MAP_GPIO_setAsInputPinWithPullDownResistor(GPIO_PORT_P5, GPIO_PIN0);
MAP_GPIO_clearInterruptFlag(GPIO_PORT_P5, GPIO_PIN0);
MAP_GPIO_enableInterrupt(GPIO_PORT_P5, GPIO_PIN0);
MAP_Interrupt_enableInterrupt(INT_PORT5);
/* Enabling SRAM Bank Retention */
MAP_SysCtl_enableSRAMBankRetention(SYSCTL_SRAM_BANK1);
/* Enabling MASTER interrupts */
MAP_Interrupt_enableMaster();
}
void SysTick_Init(void)
{
/* Setup SysTick Timer for 10ms interrupts */
System_tick_num = SystemCoreClock / system_jump_time;
if (SysTick_Config(System_tick_num))
{
// OLED_ShowStr(1, 3, "SysTick err", 2);
// OLED_ON();//OLED唤醒
while (1);
}
}
void delayMS(uint32_t num)
{
delayTarget = num;
delayCnt = 0;
delayFinFlag = 0;
while(!delayFinFlag);
}
int main(void)
{
/* Disabling the Watchdog */
MAP_WDT_A_holdTimer();
MCU_Init();
SysTick_Init();
BSP_I2C_Init();
for(i = 0; i < 4; i++)
{
// Toggle P1.0 output
GPIO_toggleOutputOnPin(GPIO_PORT_P1, GPIO_PIN0);
delayMS(250);
}
OLED_Init();
if(0 == Lsm6dso_Init())
{
OLED_ShowStr(0, 1, "PEDOMETER :", 1);
}
else
{
OLED_ShowStr(1, 3, "Lsm6dso err", 2);
OLED_ON();//OLED唤醒
while(1);
}
pedometerCnt = 0;
while(1)
{
if(Lsm6dsoEventDetected)
{
Lsm6dsoEventDetected = 0;
if(RET_OK == Get_Lsm6dso_Event(&pedoFlag))
{
pedoFlag = 0;
pedometerCnt++;
}
}
pedometerShow();
}
}
void SysTick_Handler(void)
{
if(delayCnt < delayTarget)
{
delayCnt++;
if(delayCnt >= delayTarget)
{
delayFinFlag = 1;
}
}
}
void pedometerShow()
{
stOledShow currRow;
uint32_t pedometerCntShow;
if(pedometerCntOld == pedometerCnt)
{
return;
}
pedometerCntOld = pedometerCnt;
pedometerCntShow = pedometerCnt;
index = 0;
currRow.str[MAX_ROW_STR_NUM] = 0x0;
while(pedometerCntShow > 9)
{
index++;
currRow.str[MAX_ROW_STR_NUM - index] = (pedometerCntShow % 10) + 0x30;
pedometerCntShow /= 10;
}
index++;
if(index > MAX_PEDOMETER_INDEX)
{
index = 1;
currRow.str[MAX_ROW_STR_NUM - index] = 0x21;
index++;
currRow.str[MAX_ROW_STR_NUM - index] = 0x4c;
index++;
currRow.str[MAX_ROW_STR_NUM - index] = 0x6e;
index++;
currRow.str[MAX_ROW_STR_NUM - index] = 0x6e;
index++;
currRow.str[MAX_ROW_STR_NUM - index] = 0x41;
}
else
{
currRow.str[MAX_ROW_STR_NUM - index] = (pedometerCntShow % 10) + 0x30;
}
if(indexOld != index)
{
indexOld = index;
currRow.x = 0;
currRow.y = 2;
OLED_Fill_Line(currRow.y, 0x0);
OLED_Fill_Line(currRow.y+1, 0x0);
OLED_Fill_Line(currRow.y+2, 0x0);
OLED_Fill_Line(currRow.y+3, 0x0);
}
currRow.y = 3;
currRow.TextSize = 4;
currRow.x = (ROW_PIXEL - 16 * index) / 2;
OLED_ShowStr(currRow.x, currRow.y, &currRow.str[MAX_ROW_STR_NUM - index], currRow.TextSize);
}
/* GPIO ISR */
void PORT1_IRQHandler(void)
{
uint32_t status;
status = MAP_GPIO_getEnabledInterruptStatus(GPIO_PORT_P1);
MAP_GPIO_clearInterruptFlag(GPIO_PORT_P1, status);
/* Toggling the output on the LED */
if(status & GPIO_PIN1)
{
// MAP_GPIO_toggleOutputOnPin(GPIO_PORT_P1, GPIO_PIN0);
pedometerCnt = 0;
}
}
/* GPIO ISR */
void PORT5_IRQHandler(void)
{
uint32_t status;
status = MAP_GPIO_getEnabledInterruptStatus(GPIO_PORT_P5);
MAP_GPIO_clearInterruptFlag(GPIO_PORT_P5, status);
/* Toggling the output on the LED */
if(status & GPIO_PIN0)
{
// if(GPIO_INPUT_PIN_HIGH == GPIO_getInputPinValue(GPIO_PORT_P5, GPIO_PIN0))
{
Lsm6dsoEventDetected = 1;
}
}
}
I2C调试期间遇到了很多问题，也参考了E2E上帖子解决了问题（具体的网页一时找不到了）。这里把驱动文件上传上来，可供大家参考。
