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ESP32-S31

espressif.com

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Re: ESP32-S31

#201

Earlier quoted context omitted.

What are you having trouble figuring out? ESP32 RGMII (32x) -> PHY (32x RTL8211F) -> Slave switch (6x RTL8367) -> master switch (1x) -> magnetics (for the external port). You’ll probably want a better IC for the master switch so I can’t name one of the top of my head but this would be a relatively simple, if large, PCB. The hard part I think is verifying that all the PHYs and switches will work correctly without magn…

The SoC (I was thinking about the Octavo parts) has two ethernet interfaces. We attach the interfaces to the RTL8211 and then to the switch (or do we need RTL8211s there as well? Is there a switch chip that can operate directly with the SoC ethernet ports? I am way out of my depth here. I actively avoided analog design in college, and it kind of shows. :-(

There are switches that have MAC-to-MAC skipping the PHY but only on one or two ports. I don’t know of any switch ICs that have more than two so you need to bring your own RTL8211 PHY for the rest of the ports anyway. You can just connect the SoC’s PHY directly to the switch’s ports, skipping magnetics.

There isn’t much analog design here, except the high speed digital signals for which you can just follow some basic rules of thumb (and IC routing guidelines!). You need to length match the busses and correctly route the differential pairs between the PHY and switch. If you know how to use Altium (I assume Kicad has similar features) you can do pin and part swapping with some clever placement to route only a few of the busses as short as possible, then clone them as rooms until you’ve got the number of nodes you need. The last bit will be routing the master switch that connects the slave switches and the external port.

If you’ve never done it before I’d be realistic and try to hit 100mbit first, maybe gigabit interconnection between the switches. The routing you’ll need at those slower speeds will be a lot more forgiving.

Re: ESP32-S31

#202

These little devices are extremely interesting. I have a side project I will one day get started - to place 32 SoCs (or fewer SoCs with more cores), connect them via PCB traces to an ethernet hub (I need to learn how to do that), and leave one or more "upstream" network ports for connecting multiple boards together. Each core would light up a red LED on the front-side of the board via 90-degree LED holders. Then I'd…

You can do that right now with random raspberry pi, a string of addressable leds and a tub of glue

Re: ESP32-S31

#203
post #2

Love to see more RISC-V in the wild

Why? Because company you buy stuff from didnt have to pay license? I always imagine people saying this havent seen riscv assembler code.

Re: ESP32-S31

#204
post #136
post #38

Previous discussion from two months ago, when this was announced: https://news.ycombinator.com/item?id=47561678

Damn, I’ve only checked the last month for duplicates.

Oh, I wouldn't worry about posting a dupe. Announcement vs release is different enough, and people are clearly interested in it. I didn't link it as any sort of admonition; there was just some good discussion there.

Re: ESP32-S31

#205
post #150

Earlier quoted context omitted.

I have tried one. It has no torque. For what looks like an awesome product, it does not have the power to drive a peristaltic pump. I used the same motor on a TMC stepper controller and it's completely silent and works. It's open loop, so comparing apples to oranges but I am not sure what the MKS servo driver on a motor could actually do, aside from spin unloaded.

These can deliver 2.5-3A/phase, which should ample for a pump. Respectfully, I wonder what motor was involved and whether the current was configured: they come out of the box with conservative configuration so people don't burn up motors.

Nema 17

Re: ESP32-S31

#206

Earlier quoted context omitted.

I'll mention that you usually need to put the BT connection in a low latency audio profile or else you're likely to get something more suitable for mp3-style high buffer playback.

Thanks for the tip. I'm about to revisit this again soon (new laptop + some free time for fun). Have you been able to get BT latency low enough on Windows to hit a MIDI key and hear the note without noticeable lag? It's been a few years since the last time I actually tried it myself, instead of just checking user reports. I do remember I followed the DAW company's FAQ, set a mode in the DAW, and switched something in…

Try connecting in BT HFP mode. It will limit the audio bandwidth but gives fixed, tight latency on BT2+
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