请教一下:
我的板子使用锂电池,然后通过一个3V输出的LDO来给CC2541芯片供电。然后我用1:1的两个电阻来给VBAT分压,中间接的是AIN7,也就是我要用AIN7来测量电压,进而获取VBAT的值。
但是我发现单步执行的时候测量的值是对的,但是正常的运行时候值就偏大了。
是不是ADC转换时间 不够?
Jerry:
What is the resistor value in "1:1的两个电阻来给VBAT分压" ?
The input resistance of ADC is typical 197kOhm in datasheet.
Generally, a much lower resisitor should be use for the potential divider for VBAT. A transistor may needed for switch on the divider part for ADC measurement and switch off when no ADC measuremnet to save power.