在MC68HC908SR12 datasheet Page 384页 24.14.1里表24-12描述温度斜率为:
VDD=5V±10%,GAINA=2,GAINB=6 MIN 1.275 ADCsteps/度,Typ 1.338ADCsteps/度,Max 1.372ADCsteps/度
我的电源VDD=5V±10%,GAINA=2,GAINB=6，我在程序里的设置如下：
word AD_word;
AMGCR=81;//GAINA=2,GAINB=6
AMSCR=34;//00100010
//AMCDIV[1:0]=00 Analog Module Clock Divider Control Bits,
// Set AMCDIV1 and AMCDIV0 bits to
//zero for optimum analog module performance.
//OPIFR =1 Amplifier Ready Interrupt Flag Reset,
//1 = Clear OPIF bit
//OPIF=0 Amplifier Ready Interrupt Flag
// 1 = Two-stage amplifier output is ready
//0
//DOF=0 DC Offset Flag, This is a reserved bit.
//CDIFR=1 Current Detect Interrupt Flag Reset,
//Writing a logic 1 to this write-only
//bit clears the CDIF bit.
//CDIF=0 Current Detect Interrupt Flag,
//1 = Current detect interrupt has occurred
AMCR=240;//11110000 Analog Module Control Register (AMCR)
//PWR1 PWR0=1 1 CurrentDetectModule=On
//TemperatureSensor=On Two-StageAmplifier=On
//OPCH1 OPCH0 1 1 Internal temperature sensor
//AMIEN =0 Analog module CPU interrupt requests disabled
//DO[2:0]=000 DC Offset Control Bits
//Set these bits to zero for optimum analog module performance.
while(!AMSCR_OPIF);//wait for Amplifier Ready
ADICLK=0x54;//01010100
//010 ADIV2 ADIV1 ADIV0 ADC INPUT CLOCK/4
//1 ADICLK select internal clock
//01 MODE1 MODE0 Right justified mode
ADSCR=0x00|13;//select OPOUT
while(!ADSCR_COCO);
AD_word= (ADR0H&0x03)*256+ ADR0L;
但我得到的AD转换的数据总是从690到720,什么数都有,不稳定，我觉得实际温度就是20几度，
应该如何得到正确的温度,各位牛人请帮我.万分感谢了。 | 
