P2-EC back in stock !
VonSzarvas
Posts: 3,278
Limited qty available at a special discount through the weekend with ALL product ordered today onwards shipping as RevD with the new power supply (rather than RevC as the site shows at the moment).
https://www.parallax.com/product/p2-edge-module/
If you're wanting one, better be quick ! Or join the waitlist if you miss the moment, as more will be coming over the next week.
Comments
Will a component list used for the RevD be made available?
Yes- check the last page of the schematic file attached. The docs are waiting on photos; expect them to appear at the product page soon.
(Edit: Attaching the PSRAM version schematic too, P2-EC32MB RevB)
That's a cool trick with the supply reverse protection. It took me a while to work out forward polarity operation: The internal reverse diode pulls the source up until Vgs turns the transistor on. Above that voltage it is latched-on until the supply-in gets removed. Needs > 4 Volts.
BTW: The way a FET can conduct either direction always impresses me for some reason.
And for the gotcha... make sure Vgs spec is greater than maximum Vin. Else add a zener/resistor to keep Vgs in spec. The FET here is rated +-20V Vgs as I recall, so all good with the Edge module VIN max.
Ha, so the 24 Volts I fed my EC32MB was beyond its absolute max limit. I wonder what that failure would do, hopefully not insulation punch through.
Hi @VonSzarvas
Both P2-EC-RevD, and P2-EC32MB-RevB schematics appears to hold a very minor inconsistency, apparently inherited from previous releases:
"LED's and buffer powered from LDO VIN rail (approx. 3.8V)"
... while, at the POWER page, Common_LDOin is now rated at 3.65V, and actual (37.4k/10.5k) resistive divider confirms this value (@VFB=0.800V).
Hope it helps
Henrique
Can you please send something to Mouser ?
The P2-EC32MB is not stocked! And other items are missing too.
Or Parallax is now compliant with the EU VAT rules ?
What "other items"?
I almost complained that there was no edge connector but I finally found it
I did purchase the WiFi adapter only to find that they didn't have the WiFi module
Not that I have checked every single product, however, individual P2 accessories are not available, only the whole bundle, the hyper-ram module is not available, but the most important thing is that there is no indication about the product revision, for example I got the P2 Edge rev.A when the rev.B was already available for quite some time (and I fear that the remaining stock at Mouser are still rev.A).
I think it is B. We ordered several units for our university project 2 or 3 times. We got rev. A units (with green leds) with the first order, and rev. B with the second.. That was several months ago.
Mine came from Mouser in 2021 and they are both B.
I wonder if it's feasible to reproduce the Edge module for this side of the pond.
For me, P2 pins are precious and I want them for what the P2 does best. If I need mundane stuff like SD card, etc., I'll offload it to a cheap Pico or something.
SD card doesn't eat any extra pins, as it uses the same pins as a flash, which you need to boot a P2 without a PC.
It might be possible to use just pin P63 (simplex serial) only for booting. Leaving 63 pins total for application. Although also using P62 for full-duplex would wise.
Heck, I just went off "56 I/O".... Maybe I should pay more attention to the docs
So, I am free to use 61 and everything below?
On this I/O topic, I seem to remember reading about not using certain pins for high-speed stuff(?)
And something about 32bit borders?
Unfortunately I don't have the time to be totally immersed in this stuff.
Craig
I don't think true single pin boot quite made it, but it was talked about.
It will echo the boot acks on the TX pin, but you could dual purpose that pin to a task that tolerated 'noise during boot'.
Yep, but needs a pull-up on P59 to tell the ROM not to query SPI devices for booting.
I'm guessing this depends how high. As in differences around 1.0 ns pin skew times when not registered. Registering the pins I suspect removes most of that. The simulated numbers from OnSemi weren't clear on what they applied to. See attached.
That's likely just for
addpins... although the streamer has lots of granularity steps depending on transfer word size. And of course there is A/B registers for IN/OUT/DIR.The thing was about the last 8 pin group on PortA (24..31). It shares its power supply with the clock circuit, so high-speed signals can glitch the crystal oscillator. The P2EDGE uses a funny integrated oscillator that IIRC isn't susceptible to this.
Unrelatedly, P2-EC64MB when? >u>
Oh, yes, very true. Just pins P28..31 though. P24..27 have separate VIO.
The errata needed is: If using a plain crystal then don't do FAST drive outputs on those four pins. DACs and weaker are okay.
Al-in-one oscillator modules are plenty cheap enough these days though, so it's no biggie to use one of those. I'm guessing Parallax will do this for everything from now.
Interestingly enough, my P2-EC arrived today. It is a Rev C and is exactly the same board as the unpopulated keychain I received.