Friday, 2019-03-29

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xobsMorning, all.01:04
xobsm_w: either MX25R1635FZUIH0 or GD25Q16CEIGR.  I think the factory picked the former for this run.01:05
m_wI am looking at a SOIJ part as I am not as space constrained01:10
m_wxobs, how are you flashing the bootloader in production?01:15
xobsm_w: I'm using `fomu-flash` to write the SPI flash from a Raspberry Pi, which will also run the factory test.  I'm using a test jig produced by the factory with pogo pins.01:16
xobsSO-8 parts are great.  That's what we had on the EVT board.01:19
m_wxobs, yeah I looked at the evt for inspiration01:20
m_wI want to make this as cheap as possible since I really dont have funding to make these badges01:21
m_wit is for the FOSSi latch-up conference01:21
m_wI doubt that they will be tested on the factory line so I need to come up with a simple jig or some sort01:22
m_w*of some sort01:23
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CarlFKcan the tomu touch buttons be wired to a hard switch?  someone wants to make a 1 key keyboard (Win-L - "promo thing"01:25
futarisIRCcloudCarlFK: They want to emulate a USB HID Keyboard?01:26
xobsm_w: if you do machine assembly, then chances are if one is good then most of the rest will be good.  Just need to make sure they programmed the machine correctly.01:27
tpbTitle: tomu-quickstart/usb-hid-keyboard.c at master · im-tomu/tomu-quickstart · GitHub (at
xobsLatch-up.  That did seem like an interesting conference.01:28
m_wxobs, yeah it is the north american orconf equivalent01:28
xobsYou can do programming with three wires, provided you time it right.  Plus power and ground, of course.01:29
CarlFKm_w: i know the usb side is ok - but im not sure about hooking up a switch01:29
m_wI used an FTDI breakout for programming LoFive, could probably do something similar for this01:30
m_wa physical switch?01:30
CarlFKm_w: yes01:30
m_wCarlFK, you could tack wires to the pads perhaps01:32
m_wground and power dont come out to the edge though01:33
m_wso you might drive one pin high and another low01:33
m_wthen use them as virtual power and ground and use a third pin as a GPIO input01:34
m_wyou could do 2 buttons 0 and 1, enter all of your code in binary01:35
xobsCarlFK: that'd be my suggestion. Tack wires.01:36
CarlFKone button is enough - blink the led, that's your clock.  bang in your data :p01:36
m_wbitbang all things01:37
CarlFKxobs:  shorting the wires will be the same as touching the pads?01:37
xobs<CarlFK "xobs:  shorting the wires will b"> There ought to be pull-ups as well, so you only need two.01:42
xobsCarlFK: yes, mostly. You can run it in gpio mode.01:42
xobsActually, I have an example of this.01:42
CarlFKsorry, ^w or something closed my chat tab01:42
tpbTitle: tomu-bootloader/main.c at master · im-tomu/tomu-bootloader · GitHub (at
xobsThat is what toboot uses to detect shorted pins for boot override01:46
m_wyou could do 3 buttons with this method using the internal pullups01:47
CarlFKso don't hold the key down when you power it up?  (else it prints a test page :p01:48
m_wso what do kids like on their fpga conference badges these days anyways?01:49
m_wsurely the must be consummate LEDs01:49
m_w*there must01:49
m_wcan an ICE40UP5K run from a coin cell?01:52
xobsAn Ice40up5k probably could, for a few hours. It likely uses less power than an led, depending on the Bitstream.01:59
m_wxobs, we did 2 AA on the open hardware summit badge but that seemed clunky02:01
m_wit seems the trend though looking at the ones I have here at my desk: mrrobot, ohsummit, and supercon02:02
xobsThe number "20 mAh" comes to mind for standard cr2032 batteries.02:03
xobsYou'd probably want more efficient regulators, too.02:04
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xobsOh, Energizer apparently advertises 240 mAh.02:26
xobsYou'd probably want to double them up to get ~6V.02:27
m_wI will have to make a proto and do some current measurements02:36
m_wwould want to USB to take precedence and power when connected02:37
CarlFKhow cheep can you get rechargeable?02:43
CarlFKoh god.  make a usb networking over IR badge.02:44
CarlFKim not sure what packets ... um.. some sort of store and forward when it sees the next hop.02:44
CarlFKI want to be able to send badge-mail.02:45
tpbTitle: Fully Reversible Pink/Purple USB A to micro B Cable - 1m long ID: 4111 - $3.95 : Adafruit Industries, Unique & fun DIY electronics and kits (at
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MadHackerI've seen those reversible cables a few times. On the ones I've seen there's a very thin (but stiff) PCB as the actual contact pad on the USB-A side, and it just bends to whichever side it can as you plug it in. Relies on the mating half having a chamfer on the front edge of the plastic.08:43
MadHackerThat's the A-side I'm talking about. Reversible B is new to me.08:43
MadHackerAdafruit's one looks like it's a thicker plastic bit that moves instead. Probably a better approach.08:44
MadHackerRelatedly, I finally found a proper USB-C hub, - but it's pretty damned expensive and those PCB shots look like dodgy renders. :)08:49
xobsMadHacker: fancy. nice to see they exist!08:50
xobsThough the fact that it requires a fan is somewhat concerning.08:50
xobsI guess 240W /is/ a lot of power.08:50
MadHackerYep! Suggests they're very possible but not integrated up into any sensible widgets yet.08:50
MadHackerYeah, I was less bothered by the fan than by the weird choice of the big molex power connector.08:50
MadHackerA decent barrel plug would have been far less inconvenient.08:50
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tntThe UP5k is ridiculously low power. I think the core supply was 40 mA when I toggled ~4000 flipflops at every cycle at 100 MHz and running it at 1.35v instead of 1.2v.09:45
tntPower is most likely to come from the IO and whatever you connect them to.09:46
xobstnt: Like I said, as soon as you attach an LED, you blow out any other power budget.10:09
xobsAlso, lol, I found out why USB isn't working on this Fomu DVT board.10:10
* xobs uploaded an image: fomu-jig-pin-error.jpg (129KB) < >10:10
tntah yeah, that's an issue10:19
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MadHackerxobs: Works better when the pins actually align, eh?10:35
MadHackerYou could scrape off a bit of mask on that prototype board to let it make contact maybe. It looks like there's a track in the right spot still.10:36
xobsMadHacker: yeah, I had bunnie put a very small flywire and attach some solder.  That's just an ESD diode anyway.10:37
xobsBut still, gotta get the factory to fix the jig.10:37
MadHackerHandy to have a tame bunnie for fixing your prototypes. :)10:37
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MadHackerNice, bunnie's uploaded a video of his process for patching that board.11:20
tntnice. I wonder what uv soldermask he used. The one I have doesn't work as 'glue' for wires at all.11:25
MadHackerThe stuff I have works well for it, but it needs a lot of light. I use a UV laser pointer.11:25
MadHackerIt's also a thin layers thing. Too much and it doesn't cure at all.11:26
MadHackertnt: The stuff I got was which is a thick nasty green paste. What's yours like? I've some clear stuff that's no use because it cures rubbery rather than hard.11:29
tnt MadHacker
tpbTitle: 10ml PCB UV Curable Solder Mask Repairing Fixing Anti Corrosion Paint Green | eBay (at
MadHackerThat's the style of package that my rubberier stuff is in. Looks relatively clear too, vs. quite opaque for the stuff that works well.11:33
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CarlFKCharlie Melidosian PS1 list: Carl, the tomu looks awesome! I might start with a small batch but ideally it would be in the 100+ units at a time.16:06
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CarlFKsomeone feel like adding captouch and usb-hid-keyboard together for me?18:36
CarlFKthen I can show it in action at NERP 4/8
tpbTitle: NERP - Pumping Station: One Wiki (at
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