STM32中VDDA为什么也要接电源才能烧录程序?

【STM32中VDDA为什么也要接电源才能烧录程序?】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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