将接近检测传感器集成到系统后，一个经常遇到的问题是如何正确选择接近检测的门限，以便在用户通话期间打开或关闭屏幕。门限设置须确保出现错误判断的几率非常低，而且能够支持绝大多数使用者的情况。
门限滞回例程

#define MAX44000_ADDR0x94#define INT_STATUS_REG0x00#define OFF_THRESHOLD4600#define OFF_DELAY1#define ON_THRESHOLD4000#define ON_DELAY3uint8 screenStatus;// 0 means off, 1 means on/*  i2cWriteBytes()    Arguments:uint8 address - devICe addressuint8 start_reg - register where the first byte is writtenuint8 *data - data to writeuint8 nbytes - number of bytes to write  Consecutively writes several bytes to some i2c device starting at some   specified address -- implemented elsewhere*/void i2cWriteBytes(uint8 address,uint8 start_reg,uint8 *data,uint8 nbytes);/*  MAX44000InterruptHandler()

    以下代码用于实现MAX44000 INT引脚的中断处理，假设MAX44000的接近检测传感器设置为14位模式，并已使能中断。此外，假设屏幕状态初始化为1或0，详细信息请参阅数据资料的寄存器说明部分。

*/void MAX44000InterruptHandler() {uint8 i2cData[3];i2cRead1Byte(MAX44000_ADDR,INT_STATUS_REG,&i2cData);if (i2cData&0x01 != 0)return;// check to make sure interrupt really fired// this simultaneously clears the interrupt flagif (screenStatus) {i2cData[0] = ON_DELAY;i2cData[1] = ON_THRESHOLD >> 8 & 0xBF; // set ABOVE = 0i2cData[2] = ON_THRESHOLD & 0xFF;} else {i2cData[0] = OFF_DELAY; i2cData[1] = OFF_THRESHOLD >> 8 | 0x40; // set ABOVE = 1i2cData[2] = OFF_THRESHOLD & 0xFF;} // set the new threshold depending on what the screen status was// set the delay and threshold after each interrupti2cWriteBytes(MAX44000_ADDR,0x0A,i2cData,3);return;} // MAX44000InterruptHandler

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