mmoskal

21 ms·

241.
by mmoskal 5y ago
You can’t update the ROM boot loader and it already has usb vendor and product ID assigned. For your own application you can just use random numbers as long as you are not selling this…
242.
by mmoskal 5y ago
The rotary encoders typically require quite fast sampling (~1000Hz) to be reliable when turning fast (it can be also done in hardware though). They are probably running a whole RTOS on that poor microcontroller that controls radio, so can’t
243.
by mmoskal 5y ago
To re-flash it you have to reset while holding the GPIO0 down - this starts the ROM bootloader with USB. At least this is how ESP32-S2 works.
244.
by mmoskal 5y ago
It has an USB controller, so the chip should be capable of exposing an USB drive. Unfortunately, for whatever reason they are running it through an USB-to-serial chip instead of using native USB. The same is the case for many ESP32-S2 board
245.
by mmoskal 5y ago
Travel between Schengen countries was heavily restricted for several months during the pandemic, much more so than travel between US states.
246.
by mmoskal 5y ago
I wonder what the battery life. ESP32 tend to be very power hungry with WiFi, not sure about pure BLE operation. This is why simple long-lasting (eg Withings, misfit) watches use nrf52 chips.
247.
by mmoskal 5y ago
If your heap is on the order of 100kB the GC stalls may not be so bad. A bigger problem may be pulling your code from external SPI flash - typically you will need to put all your real time code in RAM and you have only so much of it.
248.
by mmoskal 5y ago
Not quite PICO-8 but you can try https://arcade.makecode.com/ (esp. the TypeScript not blocks) - you can run these games on in-expensive (~$30) hardware [0] [0] https://arcade.makecode.com/hardware/
249.
by mmoskal 5y ago
Cortex-M4 (think $2) has 1 cycle multiplication and 2-12 cycle division (with early termination). If you go down to Cortex-M0 (think $0.50) then you get software division which is indeed order s of magnitude slower. Of course lower down th
250.
by mmoskal 6y ago
COVID induced demands for consumer electronics, while constraining supply of ICs. There's lots of low-end chips (not the CPU or GPU, but say power controllers, etc) going into laptops and peripherals (mice, keyboard, etc.). Hence the s
251.
by mmoskal 6y ago
You can try turning off WiFi if you don't need it. I found that to greatly improve battery life.
252.
by mmoskal 6y ago
We built lots of what makes Earth habitable. Try removing your clothes, housing, heating, etc. and see how long you survive. If you happen to live in a place where that doesn't kill you in a day, then if it were not for humans there wo
253.
by mmoskal 6y ago
Such a classic! I remember writing a raycasting engine in DJGPP (GCC for DOS), when I was teenager... Fast forward 25 years and hey, it can be done in TypeScript on a $2 microcontroller ;) (though it did take some effort to get TypeScript t
254.
by mmoskal 6y ago
Times are changing. You can get 32-bit MCUs for under $0.30. This will continue to fall as fabs used for MCUs are 15 years behind the high end stuff, so they have at least that much more Moore's law in them. You can say that 8-bit ones
255.
by mmoskal 6y ago
It's interesting that the "dreadfulness" of OS seems to perfectly correlated with number of users (Android, Windows, iOS, macOS, Linux).
256.
by mmoskal 6y ago
It's TWh per year, so you have to multiply your figure of 0.00445 TW (without H!) by 24*365.25 hours giving you 39TWh/year; I guess if you add cooling and different gear you can get to 120TWh/year. I agree it's kind of s
257.
by mmoskal 6y ago
If you don't feel like spending a lot you can use this https://arcade.makecode.com/hardware/dbg For the small connector you may need to buy something for a few dollars, and for the big one you almost certainly alr
258.
by mmoskal 6y ago
ESP32-S2 has both WiFi and USB. It's essentially (the classic) ESP32 cut to a single core, 320KB RAM, and with Bluetooth removed; however it does include USB. There's also ESP32-S3 which is dual core, with more RAM, USB, and Bluet
259.
by mmoskal 6y ago
$3.9t not $39t. Think about it, US GDP can't be less than $1k per person per month.
260.
by mmoskal 6y ago
You can never get RPi Zero at $5 in volume. It's always one per household, etc. It's a subsidized educational price. OTOH for this kind of board $4 seems like about the right price - RP2040 looks like ~$1 MCU to me.
261.
by mmoskal 6y ago
This exploit is about loading your own code to, and reading existing code from, a locked (encrypted) ESP32 - which is pretty bad, as it lets someone with physical access to a device to replace firmware on it, but also if you store the same
262.
by mmoskal 6y ago
It comes with UF2 (USB mass storage) bootloader in ROM
263.
by mmoskal 6y ago
F* primary aim is correctness - think something between Coq/LEAN/Isabelle and OCaml/F#. It uses a dependent type system to verify deep functional properties of programs (say that qsort actually sorts, or that a tree is balanc
264.
by mmoskal 6y ago
Here is for example a memory allocator used in micro:bit https://github.com/lancaster-university/codal-core/blob/mast... It's quite simple and extensively commented.
265.
by mmoskal 6y ago
You can't run Pi on batteries (at least not for long). If you want any input or output device, you'll have to buy it, which makes it difficult/expensive to embed in projects (eg https://makecode.microbit.org/p
266.
by mmoskal 6y ago
Yes. There's some info here https://cacm.acm.org/magazines/2020/3/243028-the-bbc-microbi... The total shipped number is now 5 million units. A significant part of these devices are in weekly use. Disclai
267.
by mmoskal 6y ago
It has a 32-bit FPU, with single cycle add and single cycle multiply; it also supports 16 bit float storage format. It lets you run small models, but note that you can't fit big ones in flash anyways. There are also some DSP instructio
268.
by mmoskal 6y ago
You can put it to sleep now from software, and also you can safely connect a LiPo battery (not only 2xAAA). There's no LiPo charging circuit on it though.
269.
by mmoskal 6y ago
The tutorial is about SAMD21 which is M0+ with VTOR. Simple bootloaders often don't need interrupts so on M0 one can get away with placing the bootloader at the end of flash and only rewriting the reset vector to lead to bootloader. Re
270.
by mmoskal 7y ago
I wrote a paper on this a few years ago http://moskal.me/pdf/prtrig.pdf though indeed getting the quantifiers to verify is more art than science...

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