Revision Request - Propeller protoboards - more silkscreen marking on bottom of board
RobotWorkshop
Posts: 2,307
If there is ever going to be another revision of the Propeller proto boards I have a request for a couple minor changes. I think they would be easy to incorporate without adding any cost to the boards.
- On the top side of the board the silkscreen has small dashes that show which pads are connected: 3.3v, 5V, GND, and the propeller output pins. Since the bottom of the board already has a silkscreen could those same dashed lines and legends for the pins also be printed on the bottom?? This would only be a change to the silkscreen. It would help when doing wiring on the bottom of the board.
- Add a spot (two pads) that go to ground and the other to the reset line. That would make it easy for someone to add a two pin header for a remote reset switch.
These are great boards to work with and I think these minor changes would make them even better.
Robert
- On the top side of the board the silkscreen has small dashes that show which pads are connected: 3.3v, 5V, GND, and the propeller output pins. Since the bottom of the board already has a silkscreen could those same dashed lines and legends for the pins also be printed on the bottom?? This would only be a change to the silkscreen. It would help when doing wiring on the bottom of the board.
- Add a spot (two pads) that go to ground and the other to the reset line. That would make it easy for someone to add a two pin header for a remote reset switch.
These are great boards to work with and I think these minor changes would make them even better.
Robert
Comments
2. Add some surface mount pads near a couple Prop pins suitable for configuring a sigma-delta ADC.
3. Use a lower-profile electrolytic cap or one with axial leads. The one that's there is the tallest thing on the board by far and severely limits one's options for an enclosure or for stacking boards. Plus, in a single, bareboard situation, it's just sitting there asking to get bumped or broken off.
Thanks,
-Phil
For larger changes that could end up being a separate prop protoboard. Maybe that would warrant a new thread about what features should be in the ultimate protoboard if there is a whole new one created.
Robert
Robert
1. Add a VIN through hole, in case somebody doesn't want to use the barrel jack (maybe an area where you could add a 3 pin servo header connection or a place for a terminal block.
2. Add power connections to the side of the board furthest away from the regulators.
3. Add the PCB traces image to the documentation: it's helpful when drilling on the board to know what you are cutting.
4. Add in a jumper to allow for separate input power supplies to the 5 v and 3.3 v regulators.
5. On the USB version of the board, break out the 5v power line so that it can be easily accessed (and four holes for a prop plug of you destroy the USB portion, like I have...).
Hello Robert,
We are planning a revision to the two Prop Proto Boards. I concur with all of your requests and I will see that they are accommodated in our revision. The power supply also needs some design improvement.
This will take some time. First, we need to finish the WiFi Module, PropBOE, and another unnamed PCB that you will learn more about in May. The manufacturing lead time is also long. I'm hoping you could wait until September before we actually have the revised board in stock.
Consider the request "booked". We'll also get to your other one sooner or later (the 12V MMWK Position Controller).
Thanks,
Ken Gracey
Hey Phil,
1. We'll look into this request. We may have introduced some other dependencies elsewhere that have frozen the location of the Propeller chip. I've also had some challenges putting a joystick and XBee adaper on this PCB for the reasons you cited. Consider this item "under consideration".
2. Can do. Would be particularly useful because it would of course accompany a pending AppNote we will release in May.
3. Right, and we agree. That capacitor almost looks like Taipei 101 the way it stands out among the other "buildings".
How come nobody suggested that we free ourselves from the Norcomp VGA/PS2 connector? We've made a very costly commitment to that part to save real estate. One problem with substituting a single VGA connector next to a single PS2 port is that we're now manufacturing enclosures that fit the Norcomp VGA/PS2 connector. Would probably be best not to replace this part.
I'll use this forum thread as our engineering task list for revisions to this product.
Thanks,
Ken Gracey
Hey David,
We can also supplement the documentation with our open-source approval. At the same time we would provide the design in DipTrace so you could easily build your own. Like all of our boards, this one is freely open for your own use. The only issue is that you need to be able to work with PADS files in this case, as it was pre-Altium, which exports nicely to DipTrace. There is no need to write us - this forum post is your approval to use the design freely, for personal or commercial use without restrictions.
Ken Gracey
Hey SRLM,
Long time, no see. You are always welcome to camp out at UPEW this May should you decide to join us. Let's go through your points:
1. OK. This could be accommodated with the power supply revision.
2. If space permits.
3. Agreed.
4. The pads are present for a 3-pin connector and jumper, though we don't include the header and jumper. What you're asking is that we populate the 3.3/5V "selector" with a jumper block, right?
5. Hmm. This would require a real estate commitment, albeit small. We will discuss, but first thoughts are that we'd rather replace boards for USB destroyers like yourself instead of make this change. This is the first time I've heard of such damage.
Great input. Thank you,
Ken Gracey
Hello Ken,
I'm doing pretty good with the Propeller boards as they are now. No hurry on the protoboard changes. I just wanted to mention it to get them on the list to see if they could be incorporated as well. I seem to do as much wiring on the bottom of the boards as on the top and having the legends for the pins replicated on the bottom would help. It came up when working on my latest project. I may a silly wiring mistake when working from the backside of the board and instead of picking an isolated pad ended up using the of the 2nd pins over that was tied to a prop pin. It was my mistake and made me think that if the dashed lines where there showing what pads were connected I may have avoided it. Didn't damage anything and once I corrected it the whole board is acting just as I hoped it would. Below is a picture that shows how it is turning out.
Robert
Ken
1. Use the same pcb for both versions by just omitting the USB/FTDI circuitry on certain builds.
2. Make the USB section with a 1x4 Propplug header and the 1x4 Propplug header to the prop immediately beside the first connector 0.1" apart. This means that you can separate the PropPlug and Prop, which is a great feature. Now, to join them just place 4 shunts to link these 2 headers.
3. Provide 2 links for 5V & Gnd so that the USB may supply the 5V, or the 5V regulator. This also permits an external 5V supply direct to the header.
I have a few other problems but am not sure of the best solutions...
4. The VGA and dual PS2 connector. It is an expensive connector and not easily obtained. Here are some ideas...
I would like to see two PS2/USB-A footprints (either a PS2 or USB-A connector can be fitted in each position). This permits modern keyboards with USB connectors working in PS2 mode to be connected. I would like to see the pullup resistors able to be linked as pulldown so that we could try USB devices such as Bluetooth and the drivers done by scanlime (cannot just think of his name).
I would prefer to ditch the VGA connector, and instead provide a 6pin header so the user can make a cable to a panel mount or backshell type VGA connector. Likewise, I would like to see a 2pin header and provision for the resistors for a TV connection.
I think there would now be enough room for a resistor and LED (uncommitted each end) so that a user could place them and a connect to any prop pin to test it.
5. Placement of the prop. I too have seen the problem where there is insufficient room whereas if it were moved more room could be gained. However, I am usnure where to move it to, and indeed if this would make the pcb any better. As a result, my thoughts are that it should remain where it is.
FWIW I agree with:
6. Adding the silkscreen legends to the underside of the pcb.
7. Adding a 2pin reset header (much better than using the power switch and easy to get an old pc reset switch on a 2pin header).
I hope this makes sense.
Since the VGA connector now has no room, What Ab
I have never encountered such great interaction with a supplier in my entire design life (almost 40 years). I have been privy to new designs from Motorola, Rockwell, SSI, AMD, Apple and the like, all under NDA of course. I have first pass engineering samples of the Motorola 88100 RISC CPU.
I only wish that more companies were like this, but then again, that is Parallax's advantage. And not only do they have this great attitude, they also have fantastic product !!!
Parallax is different (in a really, really good way) and they certainly listen to their customers. They already offer some great products and do care about suggestions to make them even better. Doesn't mean they will incorporate every request but at least they listen and consider them. More often they go well beyond that!
4. It would be nice if I could easily disable either (or both) the 5v and 3.3v regulators. Specifically, there are certain situations where I use USB power or a 5v out boost converter, and I "disable" the 5v regulator by unsoldering it. But it would be handy if I didn't have to remove it (a minor inconvenience), or even better use the regulator to provide 5v from a different power source to something like servos. Ultimately, just more power options and flexibility would be nice.
5. Replacing a board is a pain. Usually, a board for me takes maybe 5-10 hours total time to solder up, and unsoldering is unlikely. I broke the board by accidentally lifting a robot by the USB connector, and I snapped it right off. I looked into fixing it, but I when I broke the USB I tore up the pads so I just had to wire up a prop plug setup instead (and scrape off the old FTDI chip...).
Another one:
6. Add in dedicated through holes to the board and notes to the documentation about adding capacitors to overclock the board.
To pickup the /RESET line I just soldered to the side of the on-board reset switch but I'd prefer to have a pad to go to which is one of the reasons I suggested it. (And also reuse some old PC reset switches with the 2-pin header)
Robert
Can any one suggest a safe way to disconnect the VGA connector leaving it intact? Would removing the surface mount resistors going to it be enough? If so does any one know a simple way to remove surface mount resistors (I always have difficulty with those tiny things)?
We will provide our compilation of changes on this thread.
Thanks, Ken Gracey