u/FoundationOk3176

I have a custom ESP32-S3 based device which I want reduce in size further & reduce the BoM by eliminating the USB to UART chip for flashing the device.

I will still expose the pads for RX, TX, GPIO0 & nRST pins for initial flashing of the firmware but is it possible to flash the firmware using the dedicated USB peripheral & also use it for USB communication with other devices?

Perhaps, having an onboard tactile switch pressing which, followed by powering the board would put the device in update mode?

I'll be honest, I am trying to save time by seeing if it's possible to begin with.

Few months back I was trying to underclock my laptop to increase it's battery life, In my case the smallest frequency I could reach was 800 MHz.

Today suddenly it got me wondering why couldn't the CPU just be underclocked beyond a certain frequency? From my understanding of hardware, each clock cycle the CPU does something but then why does it matter how long that clock cycle is?

If anything the timing requirements would be more than lax, DDR should work just fine, The display would update at pretty horrible speeds, but it should work nonetheless?

The only reason I can think of is few peripherals that need higher clock speeds to function, Like maybe the USB 3.0 port, but if we just disregard that...

Why can't modern CPUs run at very small frequencies?

Edit: My question isn't about increasing the battery life of my laptop, The question is pretty much the title.

I want to design & build an UAV but my experience is solely limited to designing hardware & software, Thus I was wondering if there's a place I can learn how a UAV is designed so that I can design one on my own.

Particularly I want to learn how to design the mechanical side of UAVs. Like how the frame, wings, etc are designed, what kind of material to consider, what kind of motor to use, what kind of wing types & orientations to use, how to fabricate it yourself, etc.

I haven't designed any quadcopter or any kind of fixed wing aircraft before.

I have a RP2350 configured as a USB HID (Keyboard) device, In my PCB design I want to have multiple USB-C ports to allow connection with multiple USB hosts and at any given moment I want to be able to send keystrokes to any one of the connected USB hosts.

By many, I mean just 3-4 USB hosts. From what I've been able to gather is that it may be possible using a USB data mux? But I'm not sure if it'll work in the configuration I want to.

Thereby is this possible? If so, please point me in the right direction.

My front wheel is misaligned due an recent accident, The forks are twisted & I want to loosen the bottom triple clamp bolts, the stem nut & axle nuts to pump the forks and see if the wheel comes back to it's original position.

The issue is that the manufacturer of my motorcycle does not state torque values for most of the bolts on my motorcycle aside from the rear & front axle.

They do seem to have an internal service manual for their employees only but I haven't even seen a torque wrench at their service center. I doubt they really tighten things to spec.

So how can I tighten my bolts without knowing the appropriate torque?

It's a '22 Hero Xpulse 200 4V.

I am looking into designing a super simple development board around STM32MP13X MPU for learning 4-layer PCB design with BGA chip.

STM32MP13X supports upto 1 Gbyte of LPDDR2/3 & DDR3/3L SDRAM (in single rank configuration). When I was looking into sourcing the actual RAM chip, it seems that there is no standard pinout? So how can I design my board without relying on any one manufacturer because they are in low units on mouser, etc.

It seems that my best way forward is using a DDR3 SODIMM stick which seem to be easily available anywhere, but it seems that the smallest memory size I can find is 2GBytes.

So can I actually use > 1Gbyte DDR3 SODIMM stick with my STM32MP1? Intuitively I think the MPU would simply not address the extra memory but I'm not sure if that's how it would be in practice.

My minimum RAM requirement is 512 Mbytes & physical size is not a huge issue hence why I'm thinking of opting into SODIMM stick.

I am looking for a Bridge IC that can allow me to interface with NVMe drives over USB. Speed is not the primary concern, The primary concern is that it should be easily available on Mouser, Digikey or other similar sites.

Unfortunately the one's I found are not low-volume friendly at all (Looking at you Realtek).

I am using a STM32MP135 based SoM & the cheapest SoM I can find with PCIe controller is twice the cost ($51) of my current SoM ($19), Therefore I was wondering if I can find a bridge IC allowing me to access NVMe drives over USB whilst costing me $10 more at max.

If not, I would appreciate if anyone can let me know which brand might be willing to work with low-volume customers.

I'll go first:

1. Digitalism - Miami Showdown > "Let's move" > > "No point. The guy who's coming after me? Your men won't be able to stop him."
2. The Glitch Mob - Fortune Days > "What's the point in saving the world if you can't enjoy it?"

I intend on using RP2350 to interact with:

1. A USB 2.0 HCI device (with RP2350 as a host)
2. A USB 2.0 host (with RP2350 as a USB HID device)

But the RP2350 has a USB 1.1 peripheral, Thereby I was wondering if my use-case is possible?

I've been working on a device that communicates over USB but also can connect wirelessly via BLE & from what I've read so far is that any wireless device has to be tested as an intentional radiator to ensure it isn't causing interference, etc to other devices.

Now that can be avoided if I use a precertified module but even then it seems that I have to get my device tested as an unintentional radiator.

Which is fair but the cheapest numbers I could find online were $2K to $4K for unintentional radiators testing. HOW THE F AM I SUPPOSED TO DO THAT??? $2K IS LIKE WHAT I EARN FROM THE INTERNSHIP IN THE ENTIRETY OF THE YEAR! (I'm based out of India, cost of living, etc is much cheaper here & so is average income)

This is insane. As if actually designing a device, saving up to get prototypes manufactured & then assembling them myself, testing, etc isn't enough, Now I have to spend like an entire year worth of salary just to get FCC approval?

How does one even deal with this? I understand the regulations were made to ensure random junk doesn't interfere with devices, etc but it's so demotivating knowing I probably can't even sell my device after putting so much effort into designing it.

It very much encourages one to just skip it entirely & just hope to god that FCC, etc don't notice but obviously that's just in my mind.

It seems my best option might be to just ship my product with an existing FCC certified USB to Bluetooth dongle thing, but even then I'm not sure if I would have to do FCC certifications.

I am developing a product around ESP32-S3 as my requirements are BLE & USB host peripherals.

As I am entering the PCB design phase I wanted advice on whether I should use the ESP32-S3 module or the bare chip? Particularly which one would be better & cheaper for getting FCC & CE certified for America & Europe respectively.

I want to go the bare chip way because aside from the BLE & USB host peripherals, I am using absolutely nothing from the S3, Thereby I can design a much smaller PCB as compared to the module, Especially since power & range isn't a concern I want to use a ceramic chip antenna.

Thus, what should I go with? what are other issues I could get into if I don't use the module?

From what I understand, ARM TrustZone is a privilege level which allows us to hideaway sensitive operations, etc to a trusted environment and allows us to expose a very small API to systems of our choice.

But what is the point of it exactly? Why would one want to split environments into Secure & Normal world? If someone can modify Normal world's code, Can't they easily interface with the Secure world?

I am thinking of considering STM32WB35CE for a project of mine. My use case requires USB Device & BLE >= 5.0, Readout protection & Enough memory to store a 4-bit 128x96 OLED framebuffer (~6 KB).

STM32WB35CE checks all these marks but I'm seriously worried about the developer experience (DX). My previous experience with STM has been their MPU lineup.

I also don't want to use STM's IDE or whatever they call it. Thus I was wondering if anyone who has used this particular lineup or any STM32 MCU could comment on it.

There's also nRF5340 but their abomination of a packaging aQFN looks like beyond my skill set to design a PCB around.