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Ken/Hugen -

I just installed a new ST32F303 on to my original NanoVNA and it is not recognized by USB (Yes, I installed 1.5K pull-up on pin33) so I assume I need to install the DFU bootloader.

Where do I find the bootloader binary for the F303? I've looked all over.

I can install firmware successfully using my ST-link, so that is not an issue.

Did anyone create instructions for replacing the bootloader on the 'nano? I think that would be good trouble shooting info to have.

Finally, Ken - can you send me a working binary you had developed for using the F303 with the 2.8 inch display so I can verify everything works?

I ultimately want to write up a document on how to enhance the original 2.8" Nanovna with an F303 processor and maybe add an SD slot in the process.

Thanks
Larry

Hello Larry, STM32F303 comes with a bootloader, but you must connect an external 8M crystal to use DFU mode. This is why the independent 8M crystal is used on the nanoVNA-H4 instead of the 8MHz clock from the si5351. Therefore, if there is no external 8M crystal, you must use the SWD interface or UART interface to install the firmware.

hugen

Thank you for the info, hugen.
If there is no 8MHz xtal - I assume I will see the "Unknown USB device on port xx" error?
Since I can push S/W to the unit using my ST-Link,? do you know the location of any of Ken's development binaries where he was able to get the F303 working with the 2.8" LCD? At least I can check that the Nano starts-up OK with that.
Thanks!

Try this early test version, it can run on F303 without external crystal, there may be a lot of errors.

Thanks Hugen, I added an 8M xtal with 22pf caps but it won't oscillate. (I lifted pin 5 from solder pad to connect the xtal).
According to the datasheet, the F303 internal RC OSC is supposed to run at 8M if there is no external xtal.? I can program and read the chip with ST-link so I'm not sure why it's not working.?
I'll compile and load this version and see the effect. I assume this version uses MCLK for the uP?

Regards
Larry

On Thu, 4 Jun 2020 at 8:34 PM, Hugen<hugen@...> wrote: Try this early test version, it can run on F303 without external crystal, there may be a lot of errors.

Hugen,
The early FW version talks about connecting PA10 to PA12 but in your H4 schematic, it shows PA8 through R48 to PA12.? I assume R48 is not installed?
Also, what about the USB_V_IN on PA4? Do I need to sense that if using the F303?
Thanks
Larry



On Thu, 4 Jun 2020 at 8:34 PM, Hugen<hugen@...> wrote: Try this early test version, it can run on F303 without external crystal, there may be a lot of errors.

Well, unfortunately it appears I was sent a defective STM32F303.
I removed it and put the original F072 back and my Nano is working again.
I thought I might have a problem when I saw that the seller had wrapped shipping tape around the chip carrier to hold the F303 in place. So much for no antistatic precautions.

I'll have to see if the seller will send me a replacement, wrapped in aluminum foil.

On Fri, Jun 5, 2020 at 07:26 PM, Larry Rothman wrote:

STM32F303

I’m just asking in parentheses why don’t you buy from a reputable seller? With us, farnell is a good name.

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*** If you are not part of the solution, then you are the problem. ( ) ***

Yes, I think I'll order from Mouser, Newark or Digikey - they have them for around $10ea (I tried to save $$ but....)