The emulator is a duplicate investment, but I also wanted to experience like the F091. The main chip is not expensive, but the board is close to 100 yuan, so I decided to make one by myself.,P
Empty board:
Because I wanted to use the RTC, and this should be used with the official line LDO that would have to be flown a battery. I think the power consumption of the official one is too big, which is not suitable for me. To get a convenient solution, I used L series to specially to realize the low power consumption, and got an LDO with low power consumption to get a try. After all, as for the official one I should also consider its large output ability.