Search found 16 matches

by Squonk42
Mon Jul 13, 2020 7:33 am
Forum: General discussion
Topic: USBComposite send data from within interrupts
Replies: 10
Views: 2152

Re: USBComposite send data from within interrupts

I agree with Phil: IRQ handlers should be fast and short, just clear the interrupt, set some flags, record accurate time stamps, and put received data into a FIFO. Then handle all lengthy / complex operations in the main loop, possibly going back to deep sleep if there is nothing to do. And if you r...
by Squonk42
Mon Apr 06, 2020 10:17 am
Forum: General discussion
Topic: New APM32F103CB
Replies: 44
Views: 9041

Re: New APM32F103CB

Good!

So, just a simple single-precision floating point ALU with Cordic exposed in peripheral address space.

No SIMD vector or MAC operations and no saturation, so almost useless for all DSP usage.

Better than nothing :-(
by Squonk42
Sun Mar 29, 2020 10:19 am
Forum: General discussion
Topic: New APM32F103CB
Replies: 44
Views: 9041

Re: New APM32F103CB

blue-man wrote:
Sun Mar 29, 2020 8:17 am
It would not be surprising if they used something like this: https://opencores.org/projects/fpu :D
No, generally, Chinese manufacturers are not confident in Open Software / hardware, they prefer to buy a commercial IP for these kind of purpose.
by Squonk42
Sun Mar 29, 2020 10:17 am
Forum: General discussion
Topic: New APM32F103CB
Replies: 44
Views: 9041

Re: New APM32F103CB

Here is the (Google) translation for page 14: 3.10. Floating Point Unit (FPU) The product has a built-in independent FPU floating-point arithmetic processing unit, it supports the IEEE754 standard single-precision floating-point arithmetic. As it is memory-mapped on the AHB bus (0x40024000-0x400243F...
by Squonk42
Sat Mar 28, 2020 10:08 pm
Forum: General discussion
Topic: New APM32F103CB
Replies: 44
Views: 9041

Re: New APM32F103CB

Just to give you an idea about what needs to be achieved: imagine yourself having to write a documentation in Chinese for your brand new chip ;-) Most Chinese engineers are not speaking and often not reading anything but Chinese. Given their huge domestic market, they seldom put an effort in providi...
by Squonk42
Sat Mar 28, 2020 11:24 am
Forum: General discussion
Topic: New APM32F103CB
Replies: 44
Views: 9041

Re: New APM32F103CB

I only have quoted blaatshaap.be The APM32F103CB is listed here as fake: https://www.blaatschaap.be/?p=120 The stop quoting and make your own mind;-) But it is my opinion that selling undocumented functions that cannot be used can be seen as a fake functionality. Here you can read what is praised b...
by Squonk42
Fri Mar 27, 2020 10:45 pm
Forum: General discussion
Topic: New APM32F103CB
Replies: 44
Views: 9041

Re: New APM32F103CB

The STM32F103 has no FPU anyway. So if the APM32F103CB has one (peripheral) FPU and you are able to make it work, good for you, it is just a bonus. Don't call a (more or less) relatively close STM32 clone a fake, as there was no intention from the manufacturer to fool customers into thinking they ar...
by Squonk42
Thu Mar 26, 2020 5:36 pm
Forum: General discussion
Topic: New APM32F103CB
Replies: 44
Views: 9041

Re: New APM32F103CB

Yes, this is what I say: the one that are fakes are the one mounted on Bluepill boards with their marking changed, not the chips themselves.
by Squonk42
Wed Mar 25, 2020 12:56 pm
Forum: General discussion
Topic: New APM32F103CB
Replies: 44
Views: 9041

Re: New APM32F103CB

Not fake . This would mean that they are made on purpose to confuse people that they are the original part, which is not the case. These MCU all have an ARM Cortex-M core (with a legal ARM licence or not) and a more or less STM32-compatible peripheral and memory map. This is not too hard, as you can...

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