Powering a Prop Board
Buck Rogers
Posts: 2,185
in Propeller 1
Hello!
An individual I am working with wants to see evidence of my work. Call it a paperwork blizzard that person is trying to clean up after. I know that the Prop Activity Board and the Prop Project Board (USB) are designed to be externally powered. (The PAB expects to be externally powered all the time, but that isn't important here.) But what about the Quick Start Board? That seems to be the oddman out in this case. How can that board be configured to externally powered when in use away from the host computer?
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An individual I am working with wants to see evidence of my work. Call it a paperwork blizzard that person is trying to clean up after. I know that the Prop Activity Board and the Prop Project Board (USB) are designed to be externally powered. (The PAB expects to be externally powered all the time, but that isn't important here.) But what about the Quick Start Board? That seems to be the oddman out in this case. How can that board be configured to externally powered when in use away from the host computer?
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Comments
It is possible to power the Quick Start board externally via pins/pads 39 and 40 of J1 or J3.
Okay great. I'll fish one out of the pile and examine it to look for those locations. As for what the lucky board will do, I'm leaning towards the classic RGB LED driving scene.
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You can also use an external USB Battery pack and your normal USB cable to run a Quick Start Board, but you will need to use a jumper to Ground (Vss) Pin 30 (USB_PWR_EN) on the Header connector in order for the onboard power supply circuit to turn-on.
I just did this experiment on one of my Quick Start Rev A Boards, and it powered up and ran its stored program as normal. As far as I can tell from the schematics, this should also work on the Quick Start Rev B boards too.
NOTE: BE SURE TO REMOVE THE JUMPER FROM PIN 30 BEFORE CONNECTING THE QUICK START BOARD TO YOUR PC TO PREVENT DAMAGE TO THE BOARD.
Oh certainly. I believe I temporarily ran one from a classic LiPo battery once. It fired of a big storm on this list because of how it was wired. With a board from a different vendor, even though connecting the battery would deselect the USB power line, I would disconnect it, when reconnecting it to USB for reprogramming it.
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But I do not know if it would continue to work, because I didn't then mark the board with a Sharpie tag. Based on that business I am not going to use a Quick Start. Given the intended target, that it is the output function, a QS would be a bad fit. It'll probably the PAB who has an onboard regulator.
I have a few DIP profile Prop devices, I had hoped to have figured out the ultimate example for it, but, ah, time wasn't on my side then.
I also thought of using the regular Prop Project board, but using it seemed like overwork for a simple one.
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Since you mentioned a jumper a jumper on the Rev. A QuickStart, that reminded me of the "magic resistor fix" that you sometimes need to do.
http://forums.parallax.com/discussion/comment/1094355#Comment_1094355
Pin 30 is /USB_PWR_EN (Labeled /UPE) and has a description of "Allow Power Sourcing from the USB Port"
The pin explanation is:
/USB_PWR_EN — USB power enable pin, inverted. Pulled to USB 5 V supply. Internally pulled
low after successful USB power negotiation. Drive low to force the USB power input to drive the
QuickStart power supply. Drive high with 6 VDC to disable power sourcing from the USB
connector. Rev B and later boards also internally pull low /USB_PWR_EN low upon detecting a
USB charger. Rev A boards must have /USB_PWR_EN externally driven low to power from a USB
charger.
Actually no. The FTDI Chip is not involved in this.
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if you feel you're not comfortable powering the board that way, that's okay. But not what I originally had in mind.
Do you have Rev. A or B QuickStart boards?
Excellent question. These are all Rev. A, boards. Three are wearing the Retail packaging, and one in a generic antistatic bag.
What prompted it?
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