STM32F303CC on Cheap Mini Dev Board: Support for SMT32F3

I have a project where I have converted the low cost STM32F103C8 based mini development board to an STM32F303CC board. The extra performance of the F3 and its FPU were needed here for real time PID control purposes. The conversion was straight forward chip swap although I found it pushed my soldering skills some. The cost impact to the BOM is about $0.50 extra in quantity for the F3. In exchange you get an FPU and way more flash.

Project link here:
http://www.rcgroups.com/forums/showthread.php?t=2583330
See post #2 for details on the chip swap.

I’m hoping for broader support of the F3 as a target in Arduino. It is pin compatible with F1, so it would be a straight forward change for the China board suppliers to swap chips on the mini dev board. It would open up high performance real time closed loop applications to low cost Arduino STM32 applications.

Thanks,
George

@MGeo:

The official M3 support policy is: http://www.stm32duino.com/viewtopic.php?t=41

But after watching your video, I’m in the “wow mode” at your successful attempt at F3 transplant. I’ve done some work with my hot-air device and I’m a competent soldering person having my first soldering iron at age 11 to assemble a Knight Kit super-regenerative receiver. But I do not think I would tackle what you did. Congrats.

Maybe your callout for F3 Arduino support will inspire some of our members; who knows?

Ray

George,
Great work. I didn’t know about the Chip Quick stuff. That was interesting in itself.

One thing you get that I noticed is a DAC on the 303, which the 103 didn’t have. I’m sure there are other differences. It would be great to see these come out using the same board.

Michael

mrmonteith wrote:George,
Great work. I didn’t know about the Chip Quick stuff. That was interesting in itself.

One thing you get that I noticed is a DAC on the 303, which the 103 didn’t have. I’m sure there are other differences. It would be great to see these come out using the same board.

Michael

Thanks everyone for the nice comments.

mrburnette wrote:@MGeo:
Maybe your callout for F3 Arduino support will inspire some of our members; who knows?
Ray

MGeo wrote:
From Mouser.com
STM32F103C8: 2,500: $2.94
STM32F303CC: 2,500: $3.87

The 103 boards are costing me about $3.53 with free shipping. I doubt that it will cost them triple. If they can use the same boards they might go for it. It’s a matter of them getting the message.

I’ve been looking at the STM32F4 Stamp that one guy came up with. He’s not making any more but the information is out there to make new boards. I’m sure it will cost me a lot more to make it but looks intriguing still. It’s based on the STM32F405. A big jump in power too.

I guess it comes down to if you need that kind of processing power is it worth the cost difference? For me anything under $20 is reasonable enough not to worry. But I’ve got enough keeping me busy right now. Not enough time to play with all my toys.

mrmonteith wrote: I guess it comes down to if you need that kind of processing power is it worth the cost difference? For me anything under $20 is reasonable enough not to worry. But I’ve got enough keeping me busy right now. Not enough time to play with all my toys.

mrmonteith wrote:
<…>
I’ve been looking at the STM32F4 Stamp that one guy came up with. He’s not making any more but the information is out there to make new boards. I’m sure it will cost me a lot more to make it but looks intriguing still. It’s based on the STM32F405. A big jump in power too.

I cant see a lot of demand for a $20 board, when there is now the RPiZero and the CHIP , and many other similar boards in the sub $20 category, which have much more computing power, as well as more ram etc.

The price point on the ESP32 will also be interesting, as currently the price / performance on the ESP8266 is quite compelling, to the point where its worth using purely as a MCU even if you don’t want WIFi.

Also, Nordic Semi have announced an updated Bluetooth Low Energy SoC to supersede the nRF51 series, called, not surprisingly the nRF52, which is cortex M3.
Im not sure on pricing, but I was buying nRF51 modules, for around $5, which have 256k flash and 16k ram, but the nRF51 only runs at 16MHz
So anyone wanting an MCU and BLE ….

Too many choices;-)

Hopefully I didn’t miss someone already mentioning this board …
Have you all been following the new Nucleo boards, the Nucleo-32 series? Specific to this conversation would be the NUCLEO-F303K8. They are a small form factor and use the smaller 32pin chips but still have an onboard st-link v2:

Nucleo Development Boards for STs 32Pin STM32 MCUs_popup.jpg (45.63 KiB) Viewed 1839 times

Rick,
That looks purdy. I have to quit looking at shiny new boards.

Michael

MGeo wrote:
STM32F103C8: 2,500: $2.94
STM32F303CC: 2,500: $3.87

Wahoo
I just did a transplant of a F303CBT6 onto a maple mini board, and i just programmed it via an stlink v2, and it’s working XD. I’ve got blink running on it. .

Where can i take this little board from here? Is there a bootloader so i could program it via the usb port?
Should i change some settings in the board files? (i’m atm just programming it as if it’s an STM32F3Discovery).

For now i’m pretty proud i made it this far already XD. this is the first serious SMD soldering i did (i ruined one board when trying to desolder using my soldering iron, then on the next board gave it a try with my heatgun, and that was a LOT easier (even though it’s a way too big heat gun that isn’t meant for SMD work XD)).

bianchifan wrote:
I wouln’t need 2500 pcs, never ever..

MGeo wrote:At the time of this post, this link has them for US $ 5.48/ea for 5 pcs with free shipping

MGeo wrote:.
.. The point of the original post was to lobby for support of the F3 platform in the hope that demand might build. …

Roger has posted other projects, some look like they may provide F3 support https://github.com/rogerclarkmelbourne/ … o-projects

I have that F302 motor kit and Nucleo board as well, I’ll have to explore when I get a chance.

George

Will try this get some sampel of 303cc and use the heatgun to remove the 103 but it hard to hand solder the 303 and get a short that i dont find so have to find some solder paste and try again .
Jonas

Now I get my solder flux and geting soldering right.
ST-Link work …

The Koduino, Arduino core written by Avik De ( look on github) was written purely to support the F3.

It uses the Standard Peripheral Library and is constructed in totally a totally different way to Libmaple.

I think STM also intend to bring out their own core for the Nucleo F3, but its a long way down their To Do list, so I dont think its likely to be released any time soon.

racemaniac wrote:Wahoo
I just did a transplant of a F303CBT6 onto a maple mini board, and i just programmed it via an stlink v2, and it’s working XD. I’ve got blink running on it. .

Where can i take this little board from here? Is there a bootloader so i could program it via the usb port?
Should i change some settings in the board files? (i’m atm just programming it as if it’s an STM32F3Discovery).

For now i’m pretty proud i made it this far already XD. this is the first serious SMD soldering i did (i ruined one board when trying to desolder using my soldering iron, then on the next board gave it a try with my heatgun, and that was a LOT easier (even though it’s a way too big heat gun that isn’t meant for SMD work XD)).

[victor_pv – Sat May 20, 2017 10:15 pm] – I loaded the bootloader for the bluepill

What tool did you use for this?

Does the stm32f3 use the same serial protocol as the stm32f1? I did a transplant myself just now, but the STM Flash Demonstrator doesn’t recognize the patient.

I’m not aware of the F1 bootloader working on the F3.

I know the bootloader won’t work, but I’m wondering if the stm flash tool does.

OK, I figured out my problem with serial connections. I was powering the frankenpill via a laptop USB port. But that resulted in the F3 going into USB DFU mode (which enumerated correctly, but I never noticed), and the serial upload getting disabled. When I powered it from a wall charger, the serial showed up just fine.

The re-soldering was actually pretty easy.

0. Make a note of where the alignment dot on the IC is.
1. Clamp pill in vise.
2. Thread an old guitar string (=strong thin steel wire) near one side of the IC under the legs.
3. Hold guitar string with one hand and start heating the legs starting on the side where the hand is. Gently use the guitar string to pry the legs off. Repeat until side is done.
4. Repeat 2-3 for the other two sides.
5. Clean up a bit with desoldering braid. But not too much: you want to keep solder on the pads, just smooth it out.
6. Put new chip where it belongs, remembering where the alignment dot was. Align carefully with pads. This is actually rather hard. I used tweezers.
7. Gently touch a hot fine solder tip to a corner leg for 3-4 seconds. And then another, ideally (I can’t remember).
8. Repeat for other legs.
9. Check for shorts. I had one, which I fixed by cutting with an Xacto knife.

Besides the one short, I had one other problem: I wasn’t careful enough at step 3, and two legs pulled up parts of the traces. I ended putting drops of solder paste on the remaining bits of the traces hope things would join up and bridge, and it seemed to work out.

Oh, and the guitar string technique (which I saw mentioned somewhere online) bent the legs of the original F103, so it’s probably useless now.

This is only my second time ever doing surface mount soldering, and the pitch was much finer this time. My fine motor skills are pretty average, I think.

Thats an interesting technique

I tried to use a reflow tool to remove the whole IC but ended up pulling a track off the PCB, because one of the pins was not fully unsoldered.

My approach is a bit more destructive for the “old” IC but cleaner for the PCB.

I use the Xacto knife to cut all of the IC pins near the ceramic side. After cutting all of then, just remove the center and then, with the soldering iron remove all of the pins left on the PCB.
This method is not so prone to damage on the pads or on the traces of the PCB.

I’ve sort of got a blinky working with Koduino, after modifying Koduino’s f303v variant to have 128K flash / 32K ram (I am using the stm32f303cbt6).

A very happy thing: The built-in usb bootloader on the chip works fine with dfu-util for USB uploading. I had to install the zadik usb-libk driver for win64 and I do have to move the BOOT0 jumper to flash code, though.

The “sort of” is due to the delay()-based blink rate not being right. It’s too slow by about a factor of 8. I also tried using asm(“nop”) for delay, and it was also off by a similar amount. Adding some test code to the init code shows that the HSE is failing to start up, and so the chip is for some reason running at around 8-9 MHz. Any thoughts on why it might be doing that?

My oscilloscope registers nothing across the 8MHz crystal’s pins.

Problem fixed: had to remove HSEBYP bit from RCC settings.

If anybody wants to try out stm32f303cb (128k flash) or stm32f303cc (256k flash), here’s my fork of Koduino: https://github.com/arpruss/koduino

USB Serial works fine with my fork. Just do:
#include <SerialUSBClass.h>
...
setup() {
delay(200);
Serial.begin(115200, 0xff);
}


I used and stlink clone to load the bootloader. As mentioned the bootloader starts running and crash. I am sure the bootloader could be made compatible, but I just wanted to run some BIN to make sure the MCU was running (xtal pins, internal PLL, etc).

You could try the new HID bootloader that @bootsector wrote and which Vassilis has been improving .