Does the Plasma 2350 include low side current sensing (accessible via ADC3) as on the original Plasma 2040? I use the current value to dynamically determine the number of LEDs that are attached.
A quick test suggests, unfortunately, no. I have tried ADC3 GP29 and there is no significant variation (u16 in range 7 665 to 7 681) as I modulate the output of an 8 x 8 WS2812 pixels grid. I will try with a strip of 300 pixels next. [Edit: same result.]
I would really like to see the schematic. There is also no mention of logic level-shifting to 5V either. While I have not found this to be essential in the installations I have tested (R Pi Pico 1 controlling up to 300 pixels), it gave an extra bit of operational confidence with the Plasma 2040. Adafruit recommends using a level-shift to 5V for the DAT signal.
The Plasma 2350 is still very convenient for quick installs and testing, and I will continue to use it.
Is there any other test you would like me to try?
Have a look at the bottom of the pinout. It shows 5V data and 5V Clock. It is using logic level shifting to +5V.
Thank you - I missed that at a smaller scaling. Good to know. đ
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No problem, I miss stuff like that quite often.
I have the shop page set to render as large as possible, to make things easy on these old eyes. ;)
Thanks for testing this. Seems a pity they dropped the current sensor, it was a nice way to count leds. Would be good to see the schematic or get an official response from Pimoroni.
Just my observation.
The Plasma 2040 has current sensing.
The Plasma 2040 W âStickâ doesnât have it.
The Plasma 2350 is the same form factor as the 2040 Stick.
Lack of space on the Stick format?
Keeping the cost down?
It is a bit of extra parts to add / fit on the board.
And R12 needs to be able to handle the current without getting too hot in the process. I would think itâs going to be large and chunky.
Yep, Plasma 2350 doesnât have current sensing as we took the opportunity to reduce the complexity (and cost) for the stick-sized version. Nice to hear that you use this functionality though @dBerriff @rde1 - we got the impression that it wasnât very widely used.
We might bring it back in the future on a bigger, more fully featured Plasma board, if one of those happened to be in the pipeline đ
RP2350 board schematics will be forthcoming soon, waiting for engineers to return from their summer hols :)
Actually is me @rde1 using this. I send a single white value along the led strip and wait for the current to drop - allows counting of the LEDs. The current value is accurate enough for at least 120 LEDS.
I wanted to control the LEDs colours etc via wifi so I made this setup where there is a Pico W connected to the Plasma 2040 via i2c:
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Oops, apologies - going too fast.
Thatâs very clever!
One thing improved on the Plasma2350: it now exposes UART. So you can control the Plasma2350 and have I2C.
I thought there was no UART on the Plasma 2040 ⌠then I looked at the rp2040 datasheet and it shows GP20 and 21 available for UART 1. Not shown on the familiar pin out pictures for some reason.
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They are shown here, Raspberry Pi Pico GPIO Pinout for the Pico 2040.
I do believe they are preconfigured for i2c on the Plasma 2040. Thatâs the intended use anyway. As is shown on the schematic.
plasma2040.sch (shopify.com)
You wonât know if thatâs an issue until you try to repurpose them software wise.
Whatever is available on the Pico 1 for a given PIO pin is available on the Plasma 2040 for the pins that it makes accessible. The RP2040 (or 2350) chip determines what is available on a GPIO pin, not the board. A pin cannot be âpreconfiguredâ unless it is a debug, voltage or ground pin. Everything else is setup by software.
Preconfigured by software, is what I meant to convey. I got lazy in my reply. Sorry about that. :(
The library / module for the Plasma 2040 âmay possiblyâ set them up for use as shown by the board lettering. Iâll be honest and say that a lot of what goes on in the background, Micro Python wise is a mystery to me. Even more so C, which is what a lot of Pimoroniâs Micro Python code is based on / originated from.
Yes ⌠but for some reason the âofficialâ pinout diagram at:
https://www.raspberrypi.com/documentation/microcontrollers/images/pico-2-r4-pinout.svg
does not show 20 and 21 as UART. This is the image in the original Pico book also.
The diagram only shows hardware options and you cannot connect the chip UART hardware to GPIO pins 20 and 21. As these pins are connected to the QT socket, I believe the intention is that you can hook up I2C peripherals. I will attach an LCD panel.
See the UART reference here:
Just one more thing ⌠if you happen to make any new âPicoXX on boardâ products, please expose the SWD pins! I tend to use C++ and rely on the pins for quick code upload.
Lack of SWD has put me off buying many of your great PicoW on board products.
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