Is anyone interested in helping to make an Arduino Due which uses [edited:] a 100-pin STM32L471

lkcl Thu Sep 28, 2017 6:11 am

hi as i hinted at in the introduction hello here viewtopic.php?f=2&t=2629 i would like to (quickly) investigate the feasibility and viability of creating an Arduino Due compatible design which uses the 100-pin LQFP STM32F072V8T6.

the Reference Design from arduino.cc is in Eagle and is available publicly so it should be pretty straightforward and achievable. i’ve worked with the STM32F072 64-pin variant before so know what i’m doing, and love this particular series because it’s crystal-less and really really low cost. $1.66 in 10k volumes as opposed to (in the case of the ATSAM3X8E) more money than a quad-core 1.5ghz 64-bit ARM Cortex A53 processor can be bought for.

i’m aware that the 072 is only 48mhz: that’s absolutely fine for me, given that there’s a reasonable chance of hitting a BOM target that’s about the same as an 8-bit Arduino Mega 2560’s r3.

so the real question is: would anybody be interested in helping to do a feasibility study for the pinouts, help review the schematics and board designs (which i will continuously publish online – immediately – with each and every single modification made, because that’s what you do as a software libre and hardware designer) and so on.

even more than that, would anyone be interested to actually buy the resultant open hardware… or of course get it manufactured for themselves because it’s an open, libre project? the reason i ask that is, this is the arduino forum for stm32 boards… but the only boards i see which are arduino hardware-compliant are for the *uno* pinouts which was one of the very very early boards, and you only get a small range of pin-compatibility.

… and i would like to make a board that is FULLY compatible with the FULL pinout range of the *DUE*.

that would mean that people could use the FULL range of available Arduino-compatible shields in their projects.

Replies

devan Wed Oct 18, 2017 9:45 pm

On the topic of CMSIS-DAP, if you want the full mbed/Nucleo-style drag’n’drop functionality, that’s based on the DAPLINK project, which is open source (but requires Keil/IAR to build) and has been ported to the STM32F103. Off the top of my head, the DAPLink firmware weighs in at about 50KiB and the bootloader adds another 32KiB.

If you want to use a smaller chip like the F042 (I assume you want an F042 because the original chip mentioned was an F070 and the F030 doesn’t have USB), that’s almost certainly not going to fit. If you just want CMSIS-DAP for debugging and maybe some extra USB-serial, that will fit fairly comfortably in 14-15KiB.

lkcl Thu Oct 19, 2017 3:33 am

[devan – Wed Oct 18, 2017 9:45 pm] –
If you want to use a smaller chip like the F042 (I assume you want an F042 because the original chip mentioned was an F070 and the F030 doesn’t have USB), that’s almost certainly not going to fit. If you just want CMSIS-DAP for debugging and maybe some extra USB-serial, that will fit fairly comfortably in 14-15KiB.

yehyeh, the idea is to use the F030 as a near-equivalent=cost version of a USB-UART, with the advantage of flexibility which you certainly wouldn’t get from e.g. a CH340G. the F030 has USB alright, just not crystal-less operation. whatever extra can fit in its limited NAND/RAM is a huge plus.

lkcl Thu Oct 19, 2017 3:34 am

[victor_pv – Wed Oct 18, 2017 6:40 pm] –
I saw this stm32 version, but may not be for the F030:
https://github.com/x893/CMSIS-DAP
May give you a head start if you can’t find an F030 version. Not sure how large

super. i’m putting all this in the README, i know how things go with forum messages whizzing by…

devan Thu Oct 19, 2017 3:58 am

[lkcl – Thu Oct 19, 2017 3:33 am] –
the F030 has USB alright, just not crystal-less operation.

What’s your source for that? Is this one of those secret features that’s not listed on the datasheet like USB on the F101?

lkcl Thu Oct 19, 2017 4:55 am

ok, so i’m really really pissed… at myself. i got word from the factory: they can’t get hold of the STM32L471VCT6. what that means is: EVERY single one of the many, many “low-cost” taobao suppliers is FAKE.

now, normally, i apply the rule “discard immediately all parts without a huge number of suppliers, then throw out the high-cost ones, throw out the low-cost ones: what’s left is likely to be ok”.

unfortunately there were SO MANY “fake” suppliers for the STM32L471VCT6 that it hid the fact that there simply… aren’t any suppliers – at all – with this part.

so… mike would have to IMPORT it… at a cost of around $USD 12 per part. which puts a massive delay on getting it in…. which in turn means i’m not going to meet the Shenzhen Maker Faire deadline.

so…. i have 10 PCBs on the way, i am quite happy to send some to people who have better access to digikey than i do, and i could likely also get the remaining low-cost components and sell those at cost as well. alternatively, they’re all digikey-listed parts so anyone who would like to make this board up can do so.

“aaaargh” is all i can say right now.

anyway the good news is, there is plenty of time, with not having to meet the november 10th-12th deadline, on how to get a lower-cost (decent, 32-bit) arduino-compatible board using an STM32 processor.

lkcl Thu Oct 19, 2017 5:36 am

ok, i think the board *might* be rescuable… by using an STM32F427VIT6 instead. there’s a couple of differences on the power lines: also there’s some indication / hint from the STM32F427 datasheet that the STM32F10xx family are also pin-compatible. that would be extremely good news as it would appear that by accident i’ve designed something that could take e.g. an STM32F103VCT6. which _is_ extremely common and actually available, only problem being it’s 256k NAND / 64k RAM.

i think what i’ll do is grab a handful of various processors, and see how it goes, cutting tracks to make power-compatible with the F427 series as necessary, and work on a redesign after SZMF to take advantage of the fact that all these processors have USB: the F427s even also have OTG.

… whew….

martinayotte Thu Oct 19, 2017 4:30 pm

[devan – Thu Oct 19, 2017 3:58 am] –
[lkcl – Thu Oct 19, 2017 3:33 am] –
the F030 has USB alright, just not crystal-less operation.

What’s your source for that? Is this one of those secret features that’s not listed on the datasheet like USB on the F101?

F030 doesn’t have any USB …

lkcl Thu Oct 19, 2017 5:10 pm

[martinayotte – Thu Oct 19, 2017 4:30 pm] –
[devan – Thu Oct 19, 2017 3:58 am] –
[lkcl – Thu Oct 19, 2017 3:33 am] –
the F030 has USB alright, just not crystal-less operation.

What’s your source for that? Is this one of those secret features that’s not listed on the datasheet like USB on the F101?

F030 doesn’t have any USB …

… i’m an idiot! i have 2-3 other boards i’m doing, which use the F030, they’re pin-compatible, i just ordered the wrong darn part for this board, gaah. i meant to order the STM32F070 *sigh*. okaay so not such a big mess, i can at least use the F030s for the other boards when i’ve finished them. ah dearie me – thank you martin and devan for pointing out the deliberate mistake…

martinayotte Thu Oct 19, 2017 6:54 pm

The STM32F042 has the USB, but I didn’t verify the pinout compatibility.

lkcl Fri Oct 20, 2017 8:28 am

[martinayotte – Thu Oct 19, 2017 6:54 pm] –
The STM32F042 has the USB, but I didn’t verify the pinout compatibility.

ah nice, thanks martin, i’ll check it. if it’s crystal-less operation that would be extremely useful. edit: yess, it does. and pricing iis…. aa comeooon ST, Get With The Prograaaammme… it’s $0.90 for the TSSOP20 variant! nggghh i might as well use the 070 and a crystal sigh. the STM32F070F6 on st’s website is listed as $0.50 and you can get crystals for $0.10 to $0.15 – there’s no pricing incentive to buy the 040 if it’s more money than the components it’s designed to replace!

… other than that, nice find martin

pin-out-wise yes it looks like the familiar pattern i’m seeing on the 030 and the 072. checked the datasheets: yes they match. i really like that ST do that, keeping pin-compatibility.

lkcl Sun Nov 05, 2017 10:16 pm

i’ve got all the parts, and the PCBs here, i’m off to HK this morning, been very busy, will get a chance to do assembly later in the week but comms in SZ are f******d, insane censorship, you have to actually break the law and operate as a common criminal in order to communicate through certain resources. it was such hassle last time i was there i just won’t bother this time. however if i have the chance to get it assembled before the 9th i’ll take some photos and post them before going to SZ. otherwise it’ll be after the 13th.

lkcl Sun Nov 19, 2017 7:44 am

ok interestingly this time, by taking a HK SIM card with CN roaming capability, and a HK global roaming “Pokefi”, i had absolutely no censorship issues whatsoever. however the moment i went outside of the main Shenzhen area (to the Nanshan district) the 4G capability of the Pokefi cut off. ironically i was so busy at Shenzhen Maker Faire and setting up i didn’t have *time* to do assembly

at least though i was able to pick up the processors from my friend. STM32F427VIT6 i think it was. i’d really like to find something that’s not as expensive as that, yet still has a minimum of 256k RAM.