I have the following questions：
My question is for the official example: demo.STM32Cube_FW_L0_V1.7.0\Projects\STM32L053R8-Nucleo\Examples
1.There are many routines in the stm32L0 evaluation board. Some routines use the MSI as the system clock, and some routines use the HSI as the system clock. If I don't connect the crystal, should I use MSI or HSI as the clock?
2.In the STM32L0 series of ADC examples, the MSI clock is used. If I want to use the HSI clock, is there a problem? Why don't you use the HSI clock?
3.In the demo of uart, why do some examples use HSI clocks, and some examples use MSI as a clock? In actual products, I did not connect external crystal oscillator. Should I use MSI or HSI?
4.Stm32l0 series MCU, how to calculate the voltage through the value of the ADC?
Is the calculation formula as follows? If not, what should be?
VREFINT_CAL = *(__IO uint16_t *)(0X1FF80078);
Adc1 = 1.224 * VrefintCalValue * adc1 / (adc17 * 4095);
Note: adc1 is the ADC value collected on channel 1, and adc17 is the value collected on channel 17. 1.224 is the internal reference voltage.
5.The examples in the clock module all use HSI as the clock. Can I use MSI as the clock?