Another F103C8 board (but not good value)

Generic boards that are not Maple or Maple mini clones, and don't contain the additional USB reset hardware
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RogerClark
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Another F103C8 board (but not good value)

Post by RogerClark » Fri Dec 30, 2016 10:00 am

I noticed this board on AliExpress

USB To SPI I2C IIC Serial Port Adapter

https://www.aliexpress.com/item/USB-To- ... 5ce3eb61b6

Image

Looks like its pre-flashed with firmware so that it can be used as a USB to SPI etc

But the description also says
This Module can use for STM32F103C8T6 minimum system Development board If can be Programming,But we don't provide Technical Support,Please Know it.
However it would probably need to be flashed via Serial and its hard to know whether the Boot0 pin is available .

denis
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Re: Another F103C8 board (but not good value)

Post by denis » Fri Dec 30, 2016 2:29 pm


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RogerClark
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Re: Another F103C8 board (but not good value)

Post by RogerClark » Fri Dec 30, 2016 9:06 pm

I hadn't looked at their other items... It looks like they sell the Blue Pill as well

zmemw16
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Re: Another F103C8 board (but not good value)

Post by zmemw16 » Sat Dec 31, 2016 12:42 am

@denis - the picture only
this board unfortunately doesn't have the square indicating pin 1 on either the nrf or the esp connector track ends.
oh and the oled/tft pining isn't labeled either, but it does have unpopulated eprom, spi flash and sd card track / pads
srp

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Re: Another F103C8 board (but not good value)

Post by evildave_666 » Sat Dec 31, 2016 3:50 am

zmemw16 wrote:@denis - the picture only
this board unfortunately doesn't have the square indicating pin 1 on either the nrf or the esp connector track ends.
oh and the oled/tft pining isn't labeled either, but it does have unpopulated eprom, spi flash and sd card track / pads
srp
FWIW, the NRF and ESP face outward when installed on the top side of the board and the OLED pins are directly connected to the adjacent pins on the edge connector.

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Re: Another F103C8 board (but not good value)

Post by victor_pv » Mon Jan 02, 2017 4:48 pm

RogerClark wrote:I noticed this board on AliExpress

USB To SPI I2C IIC Serial Port Adapter

...

Looks like its pre-flashed with firmware so that it can be used as a USB to SPI etc
...
However it would probably need to be flashed via Serial and its hard to know whether the Boot0 pin is available .[/quote]

Would be interesting to get a hang of the source code for those "usb to XXX" functions.
We can pretty much guess the USB to serial may present itself as a USB Com port to the computer, but what about the USB-SPI for example, what driver would it use in the computer side and how it works?

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Re: Another F103C8 board (but not good value)

Post by RogerClark » Mon Jan 02, 2017 8:52 pm

Victor

I think the board operates as different devices depending on what pins you pull high or low, and is set at boot time.

I doubt its possible to get the source code, unless they are just flashing with some open source firmware for the STM32.

They are charging several dollars premium for the firmware, as the board is less functional than the Blue Pill, but costs about 3 times as much.

I guess it would be interesting to know how the SPI driver works on the PC, but I suspect it may enumerate as Serial for all functions.

It may even use Serial for I2C where the address would need to be sent before each byte of data

Controlling SPI CS etc is also an interesting point, I guess that would be done by setting DTR etc

flodejr
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Re: Another F103C8 board (but not good value)

Post by flodejr » Sat Sep 16, 2017 2:53 pm

RogerClark wrote:
Fri Dec 30, 2016 10:00 am
I noticed this board on AliExpress

USB To SPI I2C IIC Serial Port Adapter

https://www.aliexpress.com/item/USB-To- ... 5ce3eb61b6

Image

Looks like its pre-flashed with firmware so that it can be used as a USB to SPI etc

But the description also says
This Module can use for STM32F103C8T6 minimum system Development board If can be Programming,But we don't provide Technical Support,Please Know it.
However it would probably need to be flashed via Serial and its hard to know whether the Boot0 pin is available .
Hi,

I am new to STM32 altogether and I am the sucker who bought this board. This board switches between USB to I2C, USB to Serial or USB to SPI by grounding either MOSI, RXD or SDA pins and I have no idea how the I2C or SPI work, I tried all sorts of methods sending data via the USB virtual comport in I2C or SPI mode but nothing seem to work. I have attached a complete dump of the firmware from the chip. I hope I am doing it right. It is done using ST-Link and I save the entire flash memory.

If you can help see how this thing works, it will be much appreciated.
When the usb is connected to PC, it shows up as a CH340 Virtual comm port in all 3 modes.
Attachments
usbdump.zip
Firmware dump
(17.69 KiB) Downloaded 29 times

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RogerClark
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Re: Another F103C8 board (but not good value)

Post by RogerClark » Sat Sep 16, 2017 9:27 pm

Are you trying to use it as USB to Serial, or USB to SPI etc ?

DId you look in the Windows device manager to see what devices appear when you connect it with the relevant pins pulled high or low?

Edit

Flashed the code to a BluePill but the USB device comes up as unknown, and looking in the device manager, this is because the USB is not functioning correctly.

There should be value in the windows device manager for Hardware ID's, but it just appears as "USB Unknown"

Do you know what clock crystal is on that board ?

Also when you backed-up the whole flash, there seems to be less code than I'd expect,

flodejr
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Re: Another F103C8 board (but not good value)

Post by flodejr » Mon Sep 18, 2017 4:51 am

RogerClark wrote:
Sat Sep 16, 2017 9:27 pm
Are you trying to use it as USB to Serial, or USB to SPI etc ?

DId you look in the Windows device manager to see what devices appear when you connect it with the relevant pins pulled high or low?

Edit

Flashed the code to a BluePill but the USB device comes up as unknown, and looking in the device manager, this is because the USB is not functioning correctly.

There should be value in the windows device manager for Hardware ID's, but it just appears as "USB Unknown"

Do you know what clock crystal is on that board ?

Also when you backed-up the whole flash, there seems to be less code than I'd expect,
Yes, I am trying to use it as USB to Serial, USB to SPI and USB to I2C, I have successfully use it as USB to Serial but I can't figure out how to use it as USB to I2C and USB to SPI.

To switch the mode to USB to I2C, you need to ground the RX pin.
To swtich the mode to USB to SPI, you need to ground the SDA pin.
To switch the mode to USB to Serial, you need to ground the MOSI pin.

The reason why you are getting an unknown USB device is because you need to choose one of the 3 modes above, meaning you must gound one of the pins before plugging it into the computer. Once you ground one of the pins, either RX, SDA or MOSI, it will come up as a CH340 Virtual comm port for all 3 types. I am not sure what the associated RX,SDA and MOSI pins are, but most probably will be hardware serial, I2C and SPI?

Edit : I went through the traces, I suspect I2C is on I2C1, SPI is on SPI1 and UART is on UART2. There are also 3 LED indicators which will indicate what mode the board is in, the pins the LEDs are connect to I am not sure, can't see the traces.

Erm, as for the backed up, do I need to do anything on the ST-Link utility? I simply dump the device memory, I don't think it will save zero values in the file, will they, meaning it will yield 64K since it is a stm32F103C8T6 (64k) device?

As for the crystal on the board, I am not sure of smd codes, but I have enclosed a enlarged photo of what I think is the crystal. The rest looks like resistors and caps and I think one is a LDO regulator probably the 1117.
IMG_20170918_130840_BURST1_cr.jpg
IMG_20170918_130840_BURST1_cr.jpg (181.99 KiB) Viewed 590 times
Thanks for your help in trying this out.

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