VDDA为所有的模拟电路部分供电,包括:ADC模块,复位电路,PVD(可编程电压监测器),PLL,上电复位(POR)和掉电复位(PDR)模块,控制VBAT切换的开关等。即使不 使用ADC功能,也需要连接VDDA,强烈建议VDD和VDDA使用同一个电源供电。VDD与VDDA之间的电压差不能超过300mV,VDD与VDDA 应该同时上电或调电。
VDDA,VSSA是模拟部分的电源,因为它连接着复位电路,所以这个必须接,否则无法下载代码。
Power supply schemes(供电方案)
?VDD = 2.0 to 3.6 V:external power supply for I/Os and the internal regulator. Provided externally through VDD pins.
? VSSA, VDDA = 2.0 to 3.6 V:external analog power supplies for ADC, reset blocks, RCs and PLL (minimum voltage to be applied to VDDA is 2.4 V when the ADC is used)。 VDDA and VSSA must be connected to VDD and VSS, respectively.
? VBAT = 1.8 to 3.6 V:power supply for RTC, external clock 32 kHz oscillator and backup registers (through power switch) when VDD is not present.
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