minimal Custom board for STM32F103C8T6

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aaront
Posts: 3
Joined: Thu Oct 12, 2017 8:03 am

minimal Custom board for STM32F103C8T6

Post by aaront » Fri Oct 13, 2017 5:14 am

Hi,

i design a arduino connect 4 digital pin to SSR and use SPI for TFT screen with I2c touch screen. now plan to port over to Blue Pill STM32F103C8T6 . if everthing work on Blue pill. i plan to product few more unit. i have below question before produce more.

we use pin PA9, PA10 to burn our code.

1)USB didn't use at all - can we don't make the USB circuits

2)is the crystal necessary??

basically we only want the reset switch and the power IC plan to leave all other parts or IC out on the Blue Pill STM32F103C8T6 .Is that possible?

victor_pv
Posts: 1650
Joined: Mon Apr 27, 2015 12:12 pm

Re: minimal Custom board for STM32F103C8T6

Post by victor_pv » Sat Oct 14, 2017 4:33 am

The chrystal is only really necesary for USB, because the internal RC oscillator is not precise enough across the full temperature range.
But some people has even tested and used USB without and external crystal, it's just not guaranteed to work.

If you don't use USB, you should be totally find with INT HS as the clock source, and that saves a tiny bit of power if you are running on batteries.

And same about the usb circuit (3 resistors and the connector),if you don't need the usb you don't need those components.

aaront
Posts: 3
Joined: Thu Oct 12, 2017 8:03 am

Re: minimal Custom board for STM32F103C8T6

Post by aaront » Sat Oct 14, 2017 5:54 pm

HI Victor,

thank you for reply.

i need litter more help.

we follow below schematic.

http://wiki.stm32duino.com/images/c/c1/ ... ematic.pdf

from the schematic we only need below function.
1)Power(5V-->3.3V)
2)Reset
3)Boot

any idea we should keep or remove below components from the MCU section?
1)C3,C4,C10,C11 <- any idea use for what purpose??
2)Y3,C9,C12 <- any idea use for what purpose??
3)C13,C14,Y2,R6 <- i think this one is the main crystal right?

victor_pv
Posts: 1650
Joined: Mon Apr 27, 2015 12:12 pm

Re: minimal Custom board for STM32F103C8T6

Post by victor_pv » Sat Oct 14, 2017 6:57 pm

aaront wrote:
Sat Oct 14, 2017 5:54 pm
any idea we should keep or remove below components from the MCU section?
1)C3,C4,C10,C11 <- any idea use for what purpose??
2)Y3,C9,C12 <- any idea use for what purpose??
3)C13,C14,Y2,R6 <- i think this one is the main crystal right?

1) Those are needed, decoupling and filtering capacitors, one of those next to each VCC pin in the MCU. You should keep them.
2) RTC crystal. You dont need those if you dont use the RTC or use it with the internal RC as clock source
3) Those are related to the main crystal and you dont need them when using the Internal HS RC as clock source.

aaront
Posts: 3
Joined: Thu Oct 12, 2017 8:03 am

Re: minimal Custom board for STM32F103C8T6

Post by aaront » Mon Oct 16, 2017 4:09 am

Hi Victor,

thank you very much.

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