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STM32F103硬件IIC对MPR121的初始化

news 2025/9/17 17:56:31

关于MPR121，论坛可用的资料太少，大量的都是要花C币下载的资源。作为菜鸟，搞来搞去主要就是初始化配置棘手，主要就是可配置的寄存器实在太多了。根据官方MPR技术文档及网页搜索一些信息得出以下初始化函数，实测采用3mm亚克力板稳定可用。

说明：芯片为STM32F103C8T6，采用硬件IIC，管脚定义：
PB6=SCL
PB7=SDA
PB8=IRQ，中断输出。

我在IIC总线上还接了一个OLED屏。需要特别注意的是，OLED屏和MPR121对硬件IIC都有速度要求，实测必须在240K~290K之间才能正常运行，太快OLED屏会死机，太慢MPR121会死机。

MPR初始化函数如下：

void MPR121_Init(void)
{
   //复位 MPR121
   MPR121Write(0x80, 0x63);   //软复位，官方指定写入0x63值。
   MPR121Write(0x5E, 0x00);   //停止模式

   // Section A // 该组控制过滤。 data is > baseline.
   MPR121Write(MHD_R, 0x01);
   MPR121Write(NHD_R, 0x01);
   MPR121Write(NCL_R, 0x00);
   MPR121Write(FDL_R, 0x00);

   // Section B // 该组控制过滤。data is < baseline.
   MPR121Write(MHD_F, 0x01);
   MPR121Write(NHD_F, 0x01);
   MPR121Write(NCL_F, 0xFF);
   MPR121Write(FDL_F, 0x00);

   //基线过滤控制寄存器
   MPR121Write(0x33, 0x00);   //noise half delta touched
   MPR121Write(0x34, 0x00);   //noise counts touched
   MPR121Write(0x35, 0x00);   //filter delay touched

MPR121Write(0x36, 0x0F);
   MPR121Write(0x37, 0x0F);
   MPR121Write(0x38, 0x00);
   MPR121Write(0x39, 0x00);
   MPR121Write(0x3A, 0x01);
   MPR121Write(0x3B, 0x01);
   MPR121Write(0x3C, 0xFF);
   MPR121Write(0x3D, 0xFF);
   MPR121Write(0x3E, 0x00);
   MPR121Write(0x3F, 0x00);
   MPR121Write(0x40, 0x00);

   // Section C // 该组为每个电极设置触摸和释放阈值
   MPR121Write(ELE0_T, TOU_THRESH);
   MPR121Write(ELE0_R, REL_THRESH);
   MPR121Write(ELE1_T, TOU_THRESH);
   MPR121Write(ELE1_R, REL_THRESH);
   MPR121Write(ELE2_T, TOU_THRESH);
   MPR121Write(ELE2_R, REL_THRESH);
   MPR121Write(ELE3_T, TOU_THRESH);
   MPR121Write(ELE3_R, REL_THRESH);
   MPR121Write(ELE4_T, TOU_THRESH);
   MPR121Write(ELE4_R, REL_THRESH);
   MPR121Write(ELE5_T, TOU_THRESH);
   MPR121Write(ELE5_R, REL_THRESH);
   MPR121Write(ELE6_T, TOU_THRESH);
   MPR121Write(ELE6_R, REL_THRESH);
   MPR121Write(ELE7_T, TOU_THRESH);
   MPR121Write(ELE7_R, REL_THRESH);
   MPR121Write(ELE8_T, TOU_THRESH);
   MPR121Write(ELE8_R, REL_THRESH);
   MPR121Write(ELE9_T, TOU_THRESH);
   MPR121Write(ELE9_R, REL_THRESH);
   MPR121Write(ELE10_T, TOU_THRESH);
   MPR121Write(ELE10_R, REL_THRESH);
   MPR121Write(ELE11_T, TOU_THRESH);
   MPR121Write(ELE11_R, REL_THRESH);

   MPR121Write(0x59, 0x02);
   MPR121Write(0x5A, 0x01);
   MPR121Write(0x5B, 0x00);
   MPR121Write(0x5C, 0x10);
   MPR121Write(0x5D, 0x24);

   // 启用自动配置和自动重新配置
   MPR121Write(0x7B, 0x0B);
   MPR121Write(0x7D, 0xC8);
   MPR121Write(0x7E, 0x82);
   MPR121Write(0x7F, 0xB4);

//电极配置（重要）
MPR121Write(0x5E, 0xBC);//1011,1100。启用基线跟踪，启用接近检测，启用所有12个电极
}

MPR121.H文件主内容：

#define MPR121_ADD 0xB4 //（相当于0x5A<<1）将ADDR引脚连接到VSS、VDD、SDA或SCL线，得到的I2C地址分别为0x5A、0x5B、0x5C和0x5D//本例 ADDR引脚接地，故地址是0x5A

// MPR121 寄存器定义
#define MHD_R   0x2B
#define NHD_R   0x2C
#define   NCL_R   0x2D
#define   FDL_R       0x2E

#define   MHD_F   0x2F
#define   NHD_F   0x30
#define   NCL_F       0x31
#define   FDL_F       0x32

#define   ELE0_T   0x41
#define   ELE0_R   0x42
#define   ELE1_T   0x43
#define   ELE1_R   0x44
#define   ELE2_T   0x45
#define   ELE2_R   0x46
#define   ELE3_T   0x47
#define   ELE3_R   0x48
#define   ELE4_T   0x49
#define   ELE4_R   0x4A
#define   ELE5_T   0x4B
#define   ELE5_R   0x4C
#define   ELE6_T   0x4D
#define   ELE6_R   0x4E
#define   ELE7_T   0x4F
#define   ELE7_R   0x50
#define   ELE8_T   0x51
#define   ELE8_R   0x52
#define   ELE9_T   0x53
#define   ELE9_R   0x54
#define   ELE10_T   0x55
#define   ELE10_R   0x56
#define   ELE11_T   0x57
#define   ELE11_R   0x58

#define   FIL_CFG   0x5D
#define   ELE_CFG   0x5E
#define GPIO_CTRL0   0x73
#define   GPIO_CTRL1   0x74
#define GPIO_DATA   0x75
#define   GPIO_DIR   0x76
#define   GPIO_EN       0x77
#define   GPIO_SET   0x78
#define   GPIO_CLEAR   0x79
#define   GPIO_TOGGLE   0x7A
#define   ATO_CFG0   0x7B
#define   ATO_CFGU   0x7D
#define   ATO_CFGL   0x7E
#define   ATO_CFGT   0x7F

// 全局常数（实测“3/2”参数适用3mm有机玻璃板）
#define TOU_THRESH 3 //触摸阈值 0x0F 10//15//30//10//3
#define REL_THRESH 2 //释放阈值 0x0A 08//08//25//08//2

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