STM32L100R8T6 core board_IO sequence lead out

STM32L100R8T6 core board, IO is led out sequentially;
all SMD components are on the front, squeeze some solder paste and place the components on the teppanyaki and it's OK;
 
the pull-up of the USB_DP pin is controlled by PA15, Q1, R17, if you don't want to use IO For control, Q1 and R17 can be removed, and R18 can be soldered on;
 
other types of microcontrollers with the same package have not been tested. If other types of microcontrollers are used, please note that R7, C18, R19, and L1 may need to be changed accordingly.
(Actually, the STM32L100R8T6 just soldered one piece and powered it on for a test. The light came on. I didn’t write a program to test, because I don’t know anything about writing programs.)
(And it is not recommended to use other higher-performance microcontrollers, because the IO of this board’s microcontroller They are drawn out sequentially instead of nearby. In addition, I am not very good at drawing boards, and the internal wiring is messy. If the speed is too fast, big problems may occur.)
 
The window in the lower right corner of the board can be used to put something you like on the inner or top layer. Characters, two 0603 SMD LEDs can be plugged into the via holes on both sides of the window to illuminate a small area of ​​the inner layer of the board.
The current limiting resistors of these two SMD LEDs are R20 and R21 (next to C19, these two resistors have no silk screen) .
 
 
Welding the SMD LED:
 
 
It is recommended to stick some black insulating tape on the LED after soldering, otherwise it will be unsightly and light leakage will be glaring.
 
This is the effect of lighting up. The effect is average. I think it might be better to put the characters on the top layer:
 
Finally, let’s take a full picture. Friends who are hard-core are welcome to sample and test: