@profezzorn I’m about to buy a capacitor for the V2.2, and noted that the V3.9 has a “spot” for it:
- Spot for additional large capacitor if needed (helps when driving BT modules)
Is it the spot right next to the “V3.9”? Would a 0805 47UF 6.3V cap fit and work there?
Yes, that is what that spot is for, and it is sized for 0805 (or 0603) capacitors.
Hi, I had a question regarding the upgraded amount of memory on the V3 board. This isn’t a criticism, just my lack of knowledge. I am wondering why the memory “seems” so low on the board. 512k of memory, in todays standards is quite low.
I’m curious the reason for this? Is it expense of that type of memory, space on the board, other design criteria…?
Thanks for all your hard work on the proffie board, the OS and the countless other things that help all us Star Wars fans get excited about playing with our toys.
You’re not wrong. 512k of flash memory is not a lot.
However, there are no CPUs in the STM32L4 series in UFBGA64 format with more memory.
I’m not sure if this is a size restriction, a product decision, or simply because the STM32L4 series is old tech. You would have to ask ST-micro that question.
Ok. Thank you. I’m not sure the design process of the board, but from your response I’m guessing ST was part of that and it used off the shelf components to accomplish the design, which makes sense cost/time wise.
What is the limitation on higher charging that caps the v3.9 at .45A when most external chargers and charging boards use 1-3A (depending on battery size of course)?
I kept the charging low because of simplicity and safety.
500mA is what all USB ports are supposed to be capable of, so keeping it below that limit makes it easy and safe to connect to any USB port. It would be pretty annoying if you couldn’t program your board because the USB port resets because the board is drawing too much power.
Drawing more power also gets more complicated, because you need to ask the USB port for it. The CPU could do that, but I didn’t want to tie charging to the CPU, because then you could get into a situation where you can’t charge because the programming is messed up in some way.
micro-USB is also limited to 900mA, so going higher than that means switching to USB-C AND using more pins. While I do like USB-C, using more pins means that extending/relocating the port becomes annoyingly difficult.
In addition to the concerns above, high-current charging generally requires good thermal designs, and since most proffieboards will be installed in a closed space, good thermal design is not really a thing in most sabers…
There ae questions being asked, specifically about this note:
Note that some of the pads on the proffieboard are hooked up to two pins on the CPU. Those pads have two pin numbers in Arduino, and each pin number can have a different set of function. Care should be taken to not activate two different functions on connected pads, as that can make the CPU chip draw too much power, which can damage it.
Could we have an example or two of what intended use could be, and what incorrect use would be?
Thanks.
It might be easier to see once the circuit diagrams are up (which I will put up this weekend), but it’s really quite straightforward, and what is connected to what is spelled out in the “pin function table” on the V3 page:
https://fredrik.hubbe.net/lightsaber/v6/
Let’s take the “Free 3” pad as an example.
It’s hooked up to two pads on the CPU: PB11 and PC2.
PB11 has several functions: GPIO, PWM/Servo and TX4
PC2 also has several functions: GPIO, Analog and MISO2
(TX4 just means TX pin for the fourth serial port bw.)
SInce they are hooked up together, the “Free 3” pad can do all of these things.
However, it cannot do two things at the same time. The simplest example would
be if we try to do something like:
digitalWrite(9 /* PB11 */, HIGH);
digitalWrite(10 /* PC2 */, LOW);
This will create a short, and power will flow directly from one pin to the other, which can potentially damage something.
Using one pad as an input, and the other as an output would be harmless though, like:
digitalWrite(9, HIGH);
analogRead(10);
For the most part, the V3 pin map only lists one of the two pins when they are linked, which means that as long as you’re using symbolic names, it’s very difficult to mess up and damage something.
I also plan to add some code to ProffieOS which will keep track of these linked pins and prevent you from trying to use them for two things. For now there are no protections, but we also don’t use most of the functions, so it’s not very easy to do something that would be bad.
Do you plan to post the schematic?
Yes, I’m going to put the schematic on my website this weekend.
Just haven’t had the time this week.
Thanks! Sorry, I really should have read that more carefully.
I think that typical use cases for the basic user is where is the “concern” is as far as what one would need to not do until protection is in place.
Just double-check when using a NUMBER to reference a pin.
If you’re using a symbolic name from the pin map, you should be fine.
Ok, this image has too much in it. But it’s made on an Inkscape file that you turn on and off layers to get the config you want.
I don’t know how to upload it without it displaying a mess.
Have you tried the new V3 configurator?
It does most of this (except for the USB and low-power switch).
Yes, I’ve actually based most of it on the configurator. But I usually print a physical page when installing. And I don’t usually do BT nor crystal. But I will do something special with the first V3 that I can get hold of. Incidentally, I ordered 24 from Tritium and they shipped them today. So they are clearly a reliable and efficient partner. I do wonder the amount of total boards you expected to be bought on launch day? Was it in the hundreds, thousands or more order of magnitude?
It’s really hard to predict, but I would imagine it’s in the thousands.
Wow
Wow
I got a modest 2 for now.
I get to buy once a year. For installing two hilts per month. Plus, I got them for 60usd, which is a pretty nice price, considering the semiconductor current supply. I remember buying the V2 for something like 35usd in lots of 10 on Electronics123, or it was a May 4th at Korbanth. I can’t remember now. We were in paradise and didn’t knew it.
