So… i ordered some stm32f401 & f411 chips, (and a hot air smd rework station XD), and gave it a try to get one of these nice processors on a bluepill

(ok, a few tries :p)
STM is really good at keeping pin compatibility between their processors. all essential things (power supply, crystals & usb) are on the same pins on most processors (i did find an exception somewhere, always check with the cubemx tool). So i ordered a few of the 4 series chips that are also 48 pins to give it a try

If you look up these microcontrollers, you’ll notice it’s not a QFP package, but QFN, which is pretty annoying to work with, but if my current attempt worked, then it’s quite doable with a hot air station. and the pads also extend to the side a bit, so if a pin isn’t soldered properly, you should be able to add some solder to it with a fine tip and a steady hand.
After getting to know my hot air station a bit, i now have a bluepill with a stm32f401ceu6 that i’ve been able to program, and that is blinking the bluepill led . Not sure yet how well my soldering job was and if all pins will work, but this is a good start XD.
Now could we somehow convince the chinese companies making bluepills/maple minis to make these? imagine being able to buy the likes of this for < 10$ XD.
If everything is succesful, this little bluepill now has 2 DACS, 3 I2C ports, 3SPI ports (of which 2 can do I2S) and can also be a usb host, not just a device . And it can go to 84Mhz (and the spi ports are thus also faster ). And to top it off, 96kb ram, 512kb flash!
I wonder what the price difference is between teh F103C and the F401 (at 100 off quantities)
The manufacturer would probably be willing to make a batch of these, if there was sufficient order quantity e.g. 100 +
I wonder who makes the Black Pill (or the Blue Pill), as it may be worth us getting in touch with them and asking about a price.
um, baite mini maple with a 401
any others the same type of substitution might work on/with?
on aliexpress, you’re swamped with all the nucleo-401’s offered
on the stm32f401ceu6 chip, 3-4ukp, farnell uk are listing 5.50 area
someone is offering 50 for £1950, i suspect there’s a missing zero typo in there, well i’d hope so.
stephen
I’ve also got a few 413’s on the way from digikey (since i can’t find those on aliexpress).
The’re really insane 0_0 1.5Mb flash, 320kb ram, dacs, plenty of spi i2c i2s, you name it, sdio, usb host, …. it’s all there in that tiny chip that fits on a bluepill/maple mini /…
There usually is 1 small difference with the pinout of the stm32f103: they have one output pin less, because one of the pins you’re supposed to put a capacitor on for the internal reference voltage. but if not using that feature, you probably don’t even have to bother

also if we’d convince a chinese factory to produce boards like this, they might want to swap out the qfp pad for something more suited for qfn

and you can indeed find some mucleo’s 401 on aliexpress etc… but it’s again a stupid uno sized board, and 20$ is just too much for such a clumsy thing >_<.
you can indeed find the 401 for about 4-5€, and the 411 for 5-6€ a piece, so making a modded bluepill/maple mini isn’t that expensive XD.
And a maple mini with the better chip is indeed also possible . In my previous dealings with the boards however (a while back i did the same with an stm32f303 on bluepill/maple mini) i noticed that the baite pcb is a bit more delicate to switch the microcontroller on. and since it costs a lot more, i stuck with bluepills from then on. With my SMD rework station it may work better now, i’ll give it a try (finally a usage for all the maple mini, bluepill, blackpill, … boards i’ve been hoarding XD)
The’re really insane 0_0 1.5Mb flash, 320kb ram, dacs, plenty of spi i2c i2s, you name it, sdio, usb host, ….
The’re really insane 0_0 1.5Mb flash, 320kb ram, dacs, plenty of spi i2c i2s, you name it, sdio, usb host, ….
- stm32f413_f423_image.jpg (36.5 KiB) Viewed 2070 times

Would be awesome to get a board with BP form factor and F4!
a complete re-write or just a few pins ?
stephen
I wonder if you can just buy the bluepill pcb?
-rick
a complete re-write or just a few pins ?
stephen
I wonder if you can just buy the bluepill pcb?
-rick
So Its probably best to do this upgrade on the cheapest board e.g. Black Pill and not using a salvaged STM32
So Its probably best to do this upgrade on the cheapest board e.g. Black Pill and not using a salvaged STM32
for me the bluepill is the only option. The maple mini has tiny pads that are only suited for qfp, not for qfn… and the blackpill has a lot of smd components near the microcontroller… it could work, but you’ll have to fix up all the tiny resistors/capacitors afterwards >_<
*edit* after some testing i’ve noticed that if i put the 401 in a higher clockspeed, it often crashes while setting up the clock. i’m going to have a look at if it has to do with the VCAP pin that isn’t connected yet. at 24Mhz it’s running stable, at 72Mhz it often crashes.

After adding the required capacitor (4.7µF between PB11 & ground, and yes it HAS to be ceramic), my bluepill with the stm32f411CEU6 is now running stable at 96Mhz

So if you want to go for a stm32f411 bluepill, it’s possible and it works

I’ve yet to do more extensive tests with this little beast, but all signs are starting to point to the fact that this works :p.
any convenient cap to replace and / or rewire the pads
is that PB11 the bluepill pin on the pcb, or pb11 on the cpu or something entirely different ?
any other mods needed ?
stephen
any convenient cap to replace and / or rewire the pads
is that PB11 the bluepill pin on the pcb, or pb11 on the cpu or something entirely different ?
any other mods needed ?
stephen

i’m experimenting with its i2s hardware, and it’s also working

ah well, i’ve got a couple of others to try with too, mission for the weekend: get A i2s DAC properly working :p.
I wonder if you can just buy the bluepill pcb?
-rick

i’m experimenting with its i2s hardware, and it’s also working

ah well, i’ve got a couple of others to try with too, mission for the weekend: get A i2s DAC properly working :p.

i’m experimenting with its i2s hardware, and it’s also working

ah well, i’ve got a couple of others to try with too, mission for the weekend: get A i2s DAC properly working :p.

i’m experimenting with its i2s hardware, and it’s also working

ah well, i’ve got a couple of others to try with too, mission for the weekend: get A i2s DAC properly working :p.
http://www.stm32duino.com/viewtopic.php?f=39&t=1977
as well
one of the smallest and well designed development boards with many pins broken out is possibly the micropython boards
https://store.micropython.org/#/products/PYBv1_1
various other boards is reviewed in the ‘tiny stm32f4’ boards thread above
for the f4 (f405, f407) boards, i think the soc itself makes up the bulk of the cost itself as it is after all a rather complex and rather large soc ( compared to the f1) default config with 196k sram and 512 – 1m flash