Any tips for a STM32F103 board with serial to usb onboard ?

Hi,

Are there any tips / experiance on a board using the STM32F103 and having a serial <-> usb chip on board ? Like the CH340/CH341. I know the bootloader initializes the USB serial port but I find the switching between DFU and Serial not always wanted. So I’m programming with a ST-LINK V2 but then I have to connect a separate USB <-> serial convertor to use serial debugging. Would be nice to have a developboard that has this convertor on it.

Thanks.

Just found one at DX, SKU: 337043. This looks like a nice board. They even have the schematic available.
Has nice features like :
switching the +5V from USB off,
power headers for the 3.3V and 5V,
both boot jumpers,
two on board leds,
RTC xtal
two USB connectors, one connected direct to the MCU, the other one trough CH340 to UART1 pins, selectable by jumpers if you want to use them as IO.
low price

I’m going to order one, can’t go wrong for this price.

Not bad as stand-alone development board…. and as addition to your comments
– correct USB circuit
– autoreset on DTR/RTS signals of USB Serial (RTS controls BOOT0 and DTR the RESET)

OK, it has a bulky JTAG/SWD connector like ugly board, but nobody is perfect.

And another one : item 1189188234 on AliExpress. This has the bigger 128K chip, battery holder and some buttons. Can’t find the schematic, I have asked the seller if he has the schematic available. A bit more expensive but could be a nice alrounder development board.
The Prolific USB chip worry’s me, this could be fake and have issues getting it running on windows. If only it had a CH340….

rolo644u wrote:And another one : item 1189188234 on AliExpress. This has the bigger 128K chip, battery holder and some buttons. Can’t find the schematic, I have asked the seller if he has the schematic available. A bit more expensive but could be a nice alrounder development board.
The Prolific USB chip worry’s me, this could be fake and have issues getting it running on windows. If only it had a CH340….

Sure, here are the links :

http://www.dx.com/p/stm32f103c8t6-stm32 … zxBSJGLRnI

http://www.aliexpress.com/item/ARM-Cort … 88234.html

Guys

It would be great if people could add new boards to the wiki

http://wiki.stm32duino.com/index.php?ti … 103_boards

At the moment, this is very much a work in progress, and I have to individually create user accounts (on request), but I think in the long term it will be very useful if it has enough content, especially about boards, as there are so many different F103 boards

RogerClark wrote:
<…> but I think in the long term it will be very useful if it has enough content, especially about boards, as there are so many different F103 boards

Please purchase at least one (1) Baite Mini Board
Agree, I have two ! They work fine but my search was for a on-board serial to usb chip. The bootloader for the mini disconnects the serial port every time the DFU kicks in and my putty sersion is disconnected.
Or is there a way to use the USB port as serial and loading the code using a ST-LINK V2 without the DFU ?.

So this setup on one board :

mrburnette wrote:[*]ST-Link will utilize a serial protocol embedded in the chip, separate from the optional bootloader.

I ordered the board from DX.COM, when it arrives I will post some details about it.

The board arrived today. It took just 10 days to get here, that’s not bad. It cost me € 7.34. Now it’s on the bench and did some quick tests.
I noticed there were no leds blinking, so no bootloader or program was pre loaded. The serial to USB was recognized correctly as CH340 Serial port by my windows 10 pc, the other USB port did nothing, as to be expected with no bootloader present.
I connected my ST-Link V2 programmer on the JTAG pins and the board was correctly detected in the ST-LInk utility.
Next I made a blink sketch for L1 (on PA8). Flashed it using the Arduino IDE and the ST-Link V2, flashing worked fine but….no blinking led !
Next did the same on L2 (on PB15) and again, no blinking led. Thats strange, the programmer could see the chip so it’s not dead.
I did an inspection with a loupe and there was a tiny bit of solder residu pointing out on one pin, coming very close to the pin next to it, and these were the two xtal pins. With a bit of solder wick I cleaned this and connected the board again, yes, the led was blinking !
So there was a short between the two xtal pins, and the mcu clock was not working, the programmer has it’s own clock so it was no affected by this short. That’s al I have time for right now. Will do some more tests on the USB with DFU bootloader function.
There is no generic bootloader for led at PA8 (yet ) so I will use the generic_boot20_pc13.bin.
To be continued later.