New APM32F103CB

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blue-man
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Joined: Mon Mar 23, 2020 5:02 pm

Re: New APM32F103CB

Post by blue-man »

Kenjutsu wrote: Sun May 17, 2020 12:12 pm Have you tested it under STM32 Core and if so, which option did you select under Board part number?

TIA ;)
The tests have been made from another one (pegel) with the Original STM developement environment.
You can read the original Thread here https://www.mikrocontroller.net/topic/492672#6258732 but it is in german.
The Link starts where the FPU could not be detected.

At this point https://www.mikrocontroller.net/topic/492672#6258842 it becomes more clear
and then i found the above documentation https://www.apexmic.com/uploads/tool/MC ... 496340.pdf.

Result: viewtopic.php?p=2710#p2710
Kenjutsu
Posts: 27
Joined: Tue Apr 07, 2020 10:58 am
Answers: 2

Re: New APM32F103CB

Post by Kenjutsu »

FPU issues aside, does it work under STM32 Core and if so, which option did you select under Board part number? If it works as a standard Blue/BlackPill with confirmed 128k flash, then it is still a good board to buy, IMHO.

TIA
Pieter

OSX: 11.6.8
Arduino IDE: 1.8.19
PlatformIO: 6.1.4
STM32 Core: 2.3.0
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blue-man
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Re: New APM32F103CB

Post by blue-man »

Kenjutsu wrote: Sun May 17, 2020 1:33 pm FPU issues aside, does it work under STM32 Core and if so, which option did you select under Board part number? If it works as a standard Blue/BlackPill with confirmed 128k flash, then it is still a good board to buy, IMHO.
I used "BluePill F103C8" so far and it works good.
(USB, Ports, ADC, Timer)
But i didn't test the MCU funtionality in detail.

I can't say if this "clone" is better than other ones.
Maybe you can report this here?
Kenjutsu
Posts: 27
Joined: Tue Apr 07, 2020 10:58 am
Answers: 2

Re: New APM32F103CB

Post by Kenjutsu »

Thank you for the feedback. Currently, I do not have any of these boards, but I am interested in buying some since Robotdyn products are better quality than most no name products on eBay/AliExpress.
Pieter

OSX: 11.6.8
Arduino IDE: 1.8.19
PlatformIO: 6.1.4
STM32 Core: 2.3.0
Get a $5 off coupon on your first purchase at Kaiweets
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blue-man
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Re: New APM32F103CB

Post by blue-man »

Yes - why not.
It would have been a nice extra if the additional features would be present.
So it is "only" a nice clone with definite more Flash.
fanoush
Posts: 2
Joined: Thu Apr 28, 2022 9:16 pm

Re: New APM32F103CB

Post by fanoush »

Hi, just found this thread about APM32F103 chip.
Recently I got STLinkV2 clone with genuine Geehy APM32F103CBT6 chip and it looks like the FPU is working for me :-)

The chip looks like this
Image
datasheets are available here https://www.geehy.com/apm32?id=14

FPU is documented in the APM32F103x4x6x8xB User Manual pdf
I just enabled it via bit 2 of 0x40021014 and then followed manual - started fpu with operation division to register 0 (base for FPU is 0x40024000), wrote 2 arguments to 0xc and 0x10 and the result was in 0x8 register after register 0x4 showed operation is done via 1

I got this stlinkv2 clone from this aliexpress item https://www.aliexpress.com/item/1005001621626894.html but no guarantee you'll get it too (order was placed Apr 9, 2022 and I got it today).

So to sum it up this is not E variant of the chip and the FPU is working.

And BTW I flashed the dongle with Espruino JavaScript interpreter https://github.com/fanoush/EspruinoBoar ... r/STLINKV2 so testing FPU was just a few poke32/peek32 calls :-)

Code: Select all

>var f=new Float32Array(3)
=new Float32Array(3)
>var i=new Int32Array(f.buffer)
=new Int32Array(3)
>peek32(0x40021014).toString(16)
="14"
>peek32(0x40024000).toString(16)
="3130342a"
>poke32(0x40021014,0x14+8)
=undefined
>peek32(0x40024000).toString(16)
="0"
>poke32(0x40024000,1+22*2)
=undefined
>f[0]=0.5
=0.5
>f[1]=2
=2
>poke32(0x40024000+0xc,i[0])
=undefined
>poke32(0x40024000+0x10,i[1])
=undefined
>peek32(0x40024000+0x04)
=1
>i[2]=peek32(0x40024000+0x08);f[2]
=0.25
> 
fanoush
Posts: 2
Joined: Thu Apr 28, 2022 9:16 pm

Re: New APM32F103CB

Post by fanoush »

Just a small follow-up with this APM32F103CBT6 chip. I also tested running this chip at 96MHz with USB and it works too. For running at that speed it needs increased flash latency (from 2 to 3, FLASH_ACR register) and there is also extra divider 2 for usb clock. With those two changes and PLL multiplier 12 (instead of 9 for 72) it runs fine.

I got stuck a bit first because the RCC_CFGR register in STM32F103 has USBPRE prescaler defined as single bit so extending values 0,1 with 2 needed extra fixes in RCC_USBCLKConfig() method as the code was using bit banding Cortex-M feature to set single bit 22, APM32 is using reserved bit 23 too to make it two bit value.


EDIT 20 May 2022: I made another order from aliexpress store linked above and again got this exact Geehy F103CBT6 chip.
linkenzaney31
Posts: 1
Joined: Mon Jun 13, 2022 6:26 pm

Re: New APM32F103CB

Post by linkenzaney31 »

I really like RobotDyn products and have been using them for several years.
I was tempted to purchase the APM32F103CB board, but then realized that life is too short to fight against or run with the wind mills.

Now, I have turned a new leaf in my MCU projects and will focus on the F411 and H750 boards for device connected systems.
For distributed systems, I would like to have a genuine alternative from STM for ESP32 and RPI4.
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