![](data:image/png;base64,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)
Contents AN4467
2/33 DocID026156 Rev 2
Contents
1 Power supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1.1 Independent A/D converter supply and reference voltage . . . . . . . . . . . . 8
1.1.2 Independent LCD supply (STM32L0x3 only) . . . . . . . . . . . . . . . . . . . . . . 9
1.1.3 Voltage regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.2 Power supply schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
1.3 Reset and power supply supervisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.3.1 Power-on reset (POR) / Power-down reset (PDR),
Brownout reset (BOR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.3.2 Programmable voltage detector (PVD) . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.3.3 Brownout reset (BOR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.3.4 System reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2 Clocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.1 MSI clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.2 HSE OSC clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.2.1 External source (HSE bypass) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.2.2 External crystal/ceramic resonator (HSE crystal) . . . . . . . . . . . . . . . . . 18
2.3 LSE OSC clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.3.1 External crystal/ceramic resonator (LSE crystal) . . . . . . . . . . . . . . . . . . 20
2.3.2 External source (LSE bypass) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.4 Clock security system on HSE (CSSHSE) . . . . . . . . . . . . . . . . . . . . . . . . 21
2.5 HSI16 clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.6 LSI clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3 Boot configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.1 Boot mode selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2 Embedded boot loader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.3 BOOT0 pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4 Debug management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.2 SWD debug port (serial wire) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24