Hi all,
probably I’m oversizing my real actual knowledge level… but I’ve just ordered one of these…, and probably tomorrow I’ll order another one…
I haven’t any precise idea of what to do with these, but after all it was the same when I ordered the first STM32 MCU chip…
For now I’m playng with my last new useless toy… 
so there are boards like raspberry pi, beagle bone black
then there are the alternate ‘competition’
e.g.
nano pi
http://nanopi.io/nanopi-neo.html
orange pi
http://www.orangepi.org/
banana pi
http://www.banana-pi.org/
and i’m not sure what else, some of them are based on the allwinner h3 soc
which are pretty much aimed at those ‘streaming media boxes’
oh there is also the asus tinker board running a high speed rk3288
https://www.asus.com/us/Single-Board-Co … ker-Board/
and various offering from olimex – some of which based on allwinner set of ‘app processors’
https://www.olimex.com/Products/OLinuXi … e-hardware
the thing about these soc is, most of them don’t have an on chip ADC
[ag123 – Mon Jul 30, 2018 7:20 am] –
the main thing with the ‘application processors’ is that u’d need to add your own ram and flash that could be quite an effort…
Yes and this is the fun!
And “playing” with all the “problems” that a CPU like this has, like equalized traces on the pcb and others “black magic” things that I have to think about… It’s a new “adventure”! (or an other thing to put in the bin)
[ag123 – Mon Jul 30, 2018 12:07 pm] –
i think the cpu (soc) , dram, peripherals etc, tend to need different voltages than simply 3.3v as well, hence it’d mean multiple voltage regulator chips as well as a proper board design…..
Yep may be, although I haven’t checked for now. The same is for the FPGAs that I’m starting to use.
[Just4Fun – Mon Jul 30, 2018 10:09 am] –[ag123 – Mon Jul 30, 2018 7:20 am] –
the main thing with the ‘application processors’ is that u’d need to add your own ram and flash that could be quite an effort…Yes and this is the fun!
And “playing” with all the “problems” that a CPU like this has, like equalized traces on the pcb and others “black magic” things that I have to think about… It’s a new “adventure”! (or an other thing to put in the bin)
Back a few years ago, I posted here: Why …?
I think that the same question is still relevant. For example, Amazon sells an AllWinner A33 4-core tablet for under $45 and refurbished tablets can be found cheaply. This gets one into hacker-mode very quickly since the device comes fully working. It also, depending on model, provides pre-configured sensors.
Before purchase, make certain you can get root on the device by searching or doing a bit of online research. Once you have root, you essentially have a fully working Linux machine with a decent size display, etc. As a benefit, most current tablets have the USB OTG port.
My play motto is, “Maximize play, minimize cost.” For the price of a couple of movie tickets and in-theater refreshments, you have a working system to explore and hack.
Ray
a lot of useful info in your thread!
the simplest way to interface them is actually usb – (serial), no patching of pins, SPI etc simply connect them with a usb cable
for one thing Allwinner soc like H3 lacks an ADC, this can be easily handled by a BP/MM hooked up to a RPi style board.
(note that i checked the ‘low cost’ ADCs available on aliexpress / ebay etc and found that those ADCs are often much slower than STM32F103 1msps x 2, often in the order of 50-500 samples per sec, and that some of the ‘low cost’ ADCs breakouts cost as much as a bluepill despite only providing 50-500 samples per sec say on an i2c bus)
note that the original RPi would also fit the bill, hence it is a comparison of relative economy and if the boards better fit the purpose
i’ve a small dislike about some original RPi boards, which is that they use a micro usb connector to power the board.
while it is easier to get typical mobile phone charging micro-usb cables, not all cables are properly built to handle perhaps 1-2 A currents and the connector is rather flimsy (rather easy to detach)
i think an ordinary DC barrel socket better fits as a power supply connector. Some of the orange pi boards sports a separate DC barrel socket which is a nice thing.
the trouble with Cortex-M mcus like STM32F103 is that they only have 20 KB of sram and runs at 72 mhz (much faster compared to Atmega 328) but then it is still limited by the flash ram speeds i.e. the clock runs at 72 mhz (very useful for timers and divisors) but flash can only run so fast so there maybe lots of *wait states* loading instructions.
while ARM ‘app processors’ soc, clock speeds easily reaches 1 ghz and programs run from dram, and there is 256 MB – 1 GB of dram available totally blow away compared to 20k on BP/MM.
in addition to all that things like floating point / simd etc are basically part of the soc and that’s not all, those Broadcom, Allwinner etc socs and similar ones often has built-in HDMI hardware, graphics accelerators (e.g. MALI 400) and hardware media codex accelerators, often bundled with a camera CSI interface. hence the ‘app processors’ are geared for much heavier computation loads vs BP/MM etc.
hence some of the ‘heavyweight’ DSPs processing can probably be done on a RPi style app processor boards, and BP/MM handles things like ADC and various io e.g. the use of timers etc.
one of my dislike about the RPi style boards are that 40 pin connector, most of RPi’s ‘competitors’ literally copy that making the pinouts similar.
that 40 pin connector has 9 pins connected to Gnd. this leaves a mere 31 available pins for various purposes e.g. SPI and based on my examination, it seemed that the Orange Pi only routes one set of SPI pins to the 40 pin connector, i’m not sure if i may be able to configure them to expose say another set of SPI connector etc. While i think the RPi has 2 sets of SPI pins on the 40 pin connector
i think the main thing being that the ‘app processor’ soc boards are *much harder to manufacture*, requiring lots of components e.g. dram, multiple voltage regulators, many more discrete components etc. and i’d think much higher manufacturing tolerance
while an stm32 mcu board is basically wires maybe add a voltage regulator e.g. ams1117, a crystal some caps and resistors and that’s it, all the rest of the pins pull to the headers or usb connector
ST and various other Cortex-M competitors it seemed are increasingly introducing ‘super mcus’ which built-in ever larger amounts of flash and sram, some of them perhaps may leave either flash or sram out of the mcu, many of those feature the higher end A series features (e.g. Cortex-M7 etc) those would fit an increasing class of apps that has been running on A series socs thereby reducing demand for A series socs for those, leaving the A series to the expensive ‘high end’ apps, e.g. smart phones, tablets etc.
i’m thinking that stm32 & competitors may one day introduce an soc that basically has quite a bit of sram e.g. 512k – 1m and maybe 0k or only a little flash.
apps can both run from eMMC flash chips or sd cards or that they can be loaded into sram and run at much faster speeds
[ag123 – Mon Jul 30, 2018 4:14 pm] –
i’m somewhat worried of what could be a possible trend, that ‘single mcu soc’ continue to grow and ‘cannibalise’ the ‘app processor’ boards.
ST and various other Cortex-M competitors it seemed are increasingly introducing ‘super mcus’ which built-in ever larger amounts of flash and sram, some of them perhaps may leave either flash or sram out of the mcu, many of those feature the higher end A series features (e.g. Cortex-M7 etc) those would fit an increasing class of apps that has been running on A series socs thereby reducing demand for A series socs for those, leaving the A series to the expensive ‘high end’ apps, e.g. smart phones, tablets etc.i’m thinking that stm32 & competitors may one day introduce an soc that basically has quite a bit of sram e.g. 512k – 1m and maybe 0k or only a little flash.
apps can both run from eMMC flash chips or sd cards or that they can be loaded into sram and run at much faster speeds
I think you are describing the GD32 range:
http://cn.gigadevice.com/product-catego … cale=en_US
Note that the ‘flash’ on these chips is actually SRAM which is loaded at boot from on bonded serial flash.
