P2 Edge
ti85
Posts: 44
in Propeller 2
Yes...yes I look forward to these boards. It sounds like they might be in my price range and no soldering. I can’t wait to join the P2 world!
Comments
It was shown in the talk this morning, it is a P2 in (almost) Micro:bit format, the images were without the wider-pads and banana plug holes on Micro:bit.
But seeing the P2 Edge board 3D render on today’s talk, and being advised that timeline was November (only another 2 x 3 months wait?), this may be the budget entry to P2 that I’ve been waiting for?
The Edge board combined with the Breakout board looks like just what many have been waiting for from Parallax.
Fingers crossed, but in the meantime I’ll still keep an eye on P2D2 progress.
Either way, hopefully there’s some “hands on” P2 hardware on my bench to play with, before the end of 2020!
The micro:bit connector is 0.05" and those can come with 80 pins, the micro:bit PCB uses a subset of those max pins.
I think a custom pinout could allow all P2 I/O to come to the connector, but you would lose the crocodile clip / banana plug feature micro:bit has now.
It was stated that it is a bare bones P2 board, with (quote):
- 16MB SPI FLASH (128Mbit)
- 1.8V 2A switching PSU
- 3.3V 300ma LDO (for 8 I/O's?)
- 20Mhz Xtal oscilator
- 2 buffered LED's on pins 56 & 57.
- All I/O's, power, reset etc are brought out to the 80 pin edge connector!
- Don't know the cost yet.
Sounds good to me!
Here's Ken's announcement on YT (that I summarised the above from):
https://youtu.be/MfiX-UqGXVg?t=214
ie. It’s a bare bones board (as you described), plus the required 1.8V and 3.3V regulators.
I do see Parallax has their 12 way breakout module pins on the breakout accessory with could then potentially attach to a HyperRAM module, but people might like to use this Edge as an embedded device in some other system that goes into an enclosure etc. If they did that and didn't want expansion boards hanging off breakouts etc, then to make use of the high speed RAM with the P2 they'd need to design HyperRAM onto that board which gets complex if the wiring is long, and BGA is hard for average users to play with. Nicer if it's already present.
Keep it in mind anyway. It may not be feasible to include that BGA footprint into the space available, but if you could it would be useful down the track. You could fit a jumper on it's CS pin to enable the RAM only when needed in case you are worried about shorting the memory signals when people don't intend to use it. All its pins would float then.
My only concern is the height of the P2 EDGE assembly - is there a right angle edge connector available, so the P2 EDGE is essentially flat?
Something like this from DigiKey:https://digikey.com/product-detail/en/samtec-inc/MEC6-140-02-L-D-RA1/SAM9703-ND/6678440
Yes. Vertical and Right angle, SMT and Through hole options. Parallax will have the ones they use available.
For example, look at this product for the right angle connector: https://www.parallax.com/product/32710
(Although that I/O adapter is for microbit, not the P2 Edge)
Considering the connector is probably a nil cost, it just makes it easier to do a right angle connector or straight up like shown, so I think that is the major benefit to the connector, right angle will let one lower the profile.
Ship the dip pin array unsoldered, for those of us that want to wire direct, dip arrays are hard to desolder, and expose many pins to potential shorts in our projects.
Would be good for prototyping safely without a breadboard... and then use the male-to-male header to plug into a breadboard.
Something like the images attached demonstrate.
Would need some thought about all possible use cases.... and I suppose this would impact the cost for everyone having the extra header in the kit.
Maybe it's simple enough to block off un-required pins in the user application?
And another thought... I think those ribbon-cable-jumpers grab/hold better onto male pins, than into female sockets. That could be another valid reason to keep the header like the FLiP has.
I doubt it would alter costs, as the labor cost of kitting is probably just as much as running a large batch of product through the solder machine, but it might be convenient to get that option in the store..?
I can imagine one situation where I'd add right-angle 0.1" headers instead of the straight ones, and perhaps not all of them, for a certain project.
And another variant would be to have the headers pointing upward. Then you could stick a foam pad across the bottom and have a handy portable programming shoe/breakout accessory!
Totally understand how handy it would be to get a breakout that's flexible like that, for users to solder the through-hole parts as they need.
Which reminds me, - we need a mounting hole (or two) added to the breakout!
Other than that - Take my money, credit card at the ready...
This absolutely my preferred way to receive breakout boards.
Another YES from me.
Mine too. I like it.
PLEASE have a look at the offers of your competitors!!!!
How many of your potential customers do prefer this 80 pin edge connector, which needs a second board????
USB to serial is needed for programming.
Through hole for inline connectors are needed.
USB connector for power supply is needed.
(A SD-card slot offers great value)
(At the microBit this cheapest sort connector is accepted, because you can do a lot without connecting it with anything thanks to the rich features on board.)
The module includes the bare-bones circuit which is needed by most-all designs, and is ready for customer to embed in their own products. Much like the Basic Stamp concept. It's a 4-layer PCB with known good power supplies and decoupling. Customers won't need to make their own boards with 4 layer, and can design in the processor with low risk and low cost.
If USB were added to the module it increases costs for all customers who may only need to program the module once (for example).
USB connector is not required for power- 5V is connected to the edge connector directly. No need for USB cables/connectors to power the module, especially as they often do not provide >1A anyhow. Use a breadboard power supply (such as power pal), or in customer designs use a sturdy 5V regulator.
Just having a USB connector on board is not enough to make a useful system- IO breakouts (among other things) are still required which changes the dynamic of the module significantly and it is no longer a low-cost embeddable module. Keeping the module very simple suits both needs- customers that need a low-cost module, and customers that want to plug it into an adapter to develop.
Some may consider the adapter as extra baggage that could be avoided, but you need to break out the pins somehow in most cases. Think of the adapter as a Super-PropPlug if you like. Or a smaller cable could be made, with the edge-socket at one end and a prop-plug, VIN and maybe a few IO's at the other, for on-the-move development work, where packing the adapter is not preferred. This way it's just another cable, much like the USB cable.
I appreciate you are thinking about development, in which case the P2-EVAL is probably a better fit at the moment, especially for professional development, as that includes the features you mentioned and also has headers suitable for a variety of sensors and very soon the entire range of mikroE click addons.
In the future, Parallax might (we can expect "will") grow the P2-EDGE range to include one with USB and other features; this is just a starting place that suits many customers.
Last- you mentioned SD card socket... Last I looked that was in their somewhere.... Not sure which images Ken shared out, so maybe that's a surprise I just spoilt.
Or maybe not... still thinking about this...
I think Parallax have an eye more on education here, than on lowest total out of the box cost ?
The 'low-cost development board' offerings from pretty much all vendors, certainly do all have USB-serial-plus-debug, and some have USB power where that is also required & many have header pin pads.
SiLabs used to have an eval system using a edge connector, but that is now dropped as it became expensive and hard to source.
The challenge is to find an edge connector that will still be widely available in a decade ?
The Micro:bit has buttons and a display, will this P2 variant have enough included features, to demonstrate well in classrooms ?
https://www.digikey.com/product-detail/en/amphenol-icc-fci/10018784-10212TLF/609-2031-ND/1002346
I don't know what I'm missing, but it seems that the 80-pin MicroBit connector is very expensive.
Many decades ago I made modules with edge connectors, but besides being hard to get and expensive, I also needed vertical and right-angle types, and they were bulky. So, while the card looked great, you couldn't use it that way without an edge connector and a PCB to plug it into. That's why I just use pin headers now because they are so cheap and readily available in all kinds of shapes and sizes. If the Edge had USB serial onboard (such as the tiny EFM8UB3) then at least it could be operated standalone.
P.S. The EFM8UB3 + connector BOM cost is around $1.
P.S. The moral to this story is that you can't really design something well without using it yourself, and in all kinds of ways, and then you know that you have designed it well when you can use it well.
For those of us who are really cheap, we might be able to solder headers directly to the board.
I believe the 16-pin male header in this photo is 2mm pitch. 2mm headers are pretty common these days. It would be nice if this sort of option were available for us cheapskates.
Whichever way Parallax decides to do this, I'm very excited to get my hands on a few to add to some of my robots.
People initially see the cost of the CPU board (Cheaper = Better), and only later discover accessory costs like carrier boards.
It really must be as bare bones as possible, but not feel like something's missing (missing the 1.8V core voltage regulator or boot memory would be in that category).
Oh. but one thing. Reconsider the color of the blue LEDs. They're not cool anymore: white, yellow-green, amber? Fine. But not blue!
Blue LEDs have their own selection issues, just from their high VF considerations for running from 3v3 MCUs.
I've seen recent Blue LED bin-selections where they target (just) being able to work on 3v3 systems, but with really not much voltage margin at all, so not a wide-temperature.
I have used Blue LEDs to indicate 3V3 LDO input brownout - if the LED flickers dim, go find a better cable/PSU
Serial boot & Debug would also be in many users 'something's missing' basket