61–70 of 207 posts
Is anyone else worried that these chips are all made in China?
For what its worth, Espressif chips are open source, but yes, I wouldn't run national security or government devices on these. Edit: I take it back on OS comment, they are not OS but some components of the SDK are: https://zeus.ugent.be/blog/23-24/open-source-esp32-wifi-mac/
No they're not? Anyway I assume GP was asking due to procurement concerns, not security.
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IMAC are the RISC-V extensions supported: I = Base integer instruction set, 32-bit M = Standard extension for integer multiplication and division A = Standard extension for atomic instructions C = Standard extension for compressed instructions https://en.wikipedia.org/wiki/RISC-V#ISA_base_and_extensions
Thanks.I can't believe they chose non-arcane, memory-friendly letters. Kind of rare in naming hardware I feel (unless it's not ?)
The non-single-letter extensions should make you feel more at home. Like the supervisor instructions. You have Smcntrpmf which helps with benchmarking by pausing perf counters during traps. I think Smcntrpmf just rolls off the tongue nicely.
Then there's a lot of extensions that start with Z followed by a sprinkling of random letters which is secretly an abbreviation you couldn't have guessed. For instance you have your SHA-2 instructions in Zvknha and Zvknhb, since that's the Vector Krypto NIST Hashes.
Is anyone else worried that these chips are all made in China?
How do I order a few samples, seem like there is a MOQ ? Also I want to dive into hardware stuff but I'm always clueless as to what I do afterwards when this would arrive? Are you using a generic board or are you ordering and designing PCBs to hook this up to? What are you using it for ? How do I go from a prototype to mass production via kickstarter?
Typically you look for a development board with the chip embedded on it. The dev board will have a usbc port and multiple pins that can be routed to LEDs, miniscreens, audio devices, etc. To program it you can usually use Lua (a very simple embedded language, almost JS-like) or you can use C/Rust/Zig as well. Arduino IDE works for it, too. You code from desktop and upload ROMs via USBC. You can plug the dev board int…
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>> And the CPU even has SIMD instructions! Yes, but it looks like there is no hardware floating point. The description of the CORDIC module indicates fixed-point calculations, which is consistent with the lack of any reference to floating point. I am happy the have CAN-FD and Motor PWM module, but nowhere did I see conversion times listed for the ADC. For motor control I demand 1uS conversion time or less, and in the…
Also why do you need 1uS for motor control? 1uS is 0.1 degrees of rotation at 16,666 RPM if I did the math right. I don't know much about motor control, is it normal to need that fast of feedback?
It's not that important if you use current sensors on the motor phases. But then you're looking at HALL sensors or a shunt with a very high gain amplifier with good common mode rejection - looking for mV signals on top of a +12V or +48V square wave at PWM frequency.
By using low-side shunts under each half-bridge you don't need the common mode rejection, but you can only measure phase current while the low side FET for that phase is on. That means limiting the PWM duty cycle to ensure that FET is on long enough to measure current, so we trade available voltage range for sample time.
I've also written code to measure all phase voltages with a single low-side current shunt under the whole 3-phase bridge. That requires careful phase shifting of the PWM signals and very fast conversion time, but you don't have to compromise available voltage range 0-100 percent duty cycle is possible.
Typically we run the control loop at PWM frequency, but the measurements need to be faster than that.
Earlier quoted context omitted.
>> And the CPU even has SIMD instructions! Yes, but it looks like there is no hardware floating point. The description of the CORDIC module indicates fixed-point calculations, which is consistent with the lack of any reference to floating point. I am happy the have CAN-FD and Motor PWM module, but nowhere did I see conversion times listed for the ADC. For motor control I demand 1uS conversion time or less, and in the…
Also why do you need 1uS for motor control? 1uS is 0.1 degrees of rotation at 16,666 RPM if I did the math right. I don't know much about motor control, is it normal to need that fast of feedback?
Fast feedback loops are also necessary in SMPS, another area where precision, low latency MCU peripherals and software are actively displacing traditional approaches.
I kind of wish these all weren't called ESP32. ESP8266 and ESP8285 -> ESP32 made sense, but now we have 10+ different versions with different features and different architectures. Kind of like how in every thread involving a Raspberry Pi Pico (RP2030/RP2350), there's always someone confusing it with the single board computer version. The ESP32 (Classic, usually WROOM-32E) is still usually what comes to mind when I he…
Their product naming could be better; S3 is going to show S31 in the search results.
I'm interested in audio out because I dabble in musical instruments. What's the state of Bluetooth audio out on microcontrollers? Is low latency and high quality output possible?
Sorry, I don't know. I'm just responding to echo and expand on another reply that Bluetooth for anything related to serious music, from audio playback to MIDI input is a dumpster fire on Windows.
Several years ago I tried to set up a high-end Windows laptop for hobby DAW composition on the go. The real-world BT audio latency just from laptop to headphones/earbuds was unworkable and, separately, the input latency from BT midi controllers was unworkable. Stacked together the total lag was laughable.
At the time, the issues were widely known and much lamented. Some tech blogs (including one at MSFT) indicated there were issues at every level of the stack (drivers, firmware, silicon) and work was proceeding to address the end to end shit show. The only workable Windows solutions referenced online involved using specific non-Bluetooth wireless devices. Needing to have a dedicated USB dongle hanging off the laptop combined with having a choice of either one specific device or a receiver dongle to support all devices, is less appealing than just having a wire.
Since then I've looked again every year or so but have seen no reports yet of meaningful progress and there's even less discussion of work in progress. Very disappointing. And the situation on the BT audio quality side doesn't seem much better. If you don't want degraded audio quality it's either choosing very specific devices which support a proprietary BT codec or switching to non-BT wireless dongle hardware. At least there is talk of improvement on audio quality but no clear indication better baseline minimum audio quality will ever be mandated in the BT audio standard.
If anyone has info the baseline latency or quality (input or output) of standard BT devices in Windows configs will improve, I'd be delighted to hear it.
I kind of wish these all weren't called ESP32. ESP8266 and ESP8285 -> ESP32 made sense, but now we have 10+ different versions with different features and different architectures. Kind of like how in every thread involving a Raspberry Pi Pico (RP2030/RP2350), there's always someone confusing it with the single board computer version. The ESP32 (Classic, usually WROOM-32E) is still usually what comes to mind when I he…