QProbe - Ordering, Building, Downloads

Parent Category: Tools Category: QProbe - a QBUS signal adapter Written by Administrator

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In case you find QProbe useful, you can get it. Either you build yourself from the attached files, or you order it.

Use cases

Blinkenlight modes



QProbe consists of these physical modules

  • The main PCB, a quad-layer with gold fingers.
    Best you order with SMD assembled.
    The PCB can be produced by every maker via the given Gerber files.
    The SMD assembly requires two special files for BOM (Bill Of Material) and positions, the attached ones are only suitable for the chinese maker JLCPCB.
  • the front panel template with LED holes. Its a PCB without copper layer, only color and drill holes, so it can be made together with the main PCB. Choose "black" color, 1.2mm tickness, and tell the manufacturer NOT to print his order numebr onto the board.
  • The body for the 1.8mm LEDs. It is given as STL file and can be printed on every 3D printer. As it has fine details, the printer must have fairly high quality. I used a Prusa MK3S.

 For the THT ("through-the-hole") components see the 2nd attached BOM.

Assembly: there's not much to say for the soldering part.

The LEDs are mounted in two passes: First open the pin holes in the 3D body with a 1mm drill. Then insert the lower LED row (IAK..+12V), make sure they all sit deep in their openings and fiddle all the pins through the PCB (that is the hard part as all LEDs are mounted simultaneously). Verify the front panel is mountable onto all the lower LEDs. Mount the LED body the PCB. Then mount the upper LEDs one-by-one, which is more easy. Again verify the front panel. Solder at last.

<bild: LED oreintation>

The front panel PCB is just snapped onto the 60 LEDs. It may need rework, then open the LED holes with a 2mm drill.

<bild: frontpanel liegt for 3D LED body>


After soldering all parts together you need to program the two CPLDs. These are Intel (ex Altera) EPM240T100.
For programming you need

  • work on a Win10 platform.
  • buy a programming adapter: search on eBay for "altera usb blaster", it should be $5 to $10.
  • install the "Intel Quartus Prime Lite Edition". This is quite a big pack, also stand-alone programmers are available.
  • After installing Quartus, plug in USBBlaster and install its driver, which is well hidden inside the Quartus file tree.
    For me it was "c:\intelFPGA_lite\20.1\quartus\drivers\usb-blaster-ii\".
  • Then power the QPRobe board with +5V, plug USBBlaster onto the JTAG header, start Quartus, go to the Tools/Programmer menu, select your USBBlaster as hardware, "Detect" both CPLDs, and load each of the both *pof" file into its matching CPLD.


To verify your build, plug in bus termination resistor packs, apply +5V power to the board and set the CPLD mode switches 1 and 2 to ON. Then touch each QBUS signal pin with a GND wire to activate them one-by-one (QBUS signals are inverted: a logic 1 is presented by 0 volt signal level). Verify the selected LEDs are shining. For BDAL<15:0>, both an ADDR and a DATA LED are active together if switch 2 is ON.


Missing attachements

cpld1. pof

cpld2 pof

Mouser BOM


Download this file (qprobe-bom_jlcpcb.csv)qprobe-bom_jlcpcb.csv[SMD Bill Of Material for JLCPCB]8 kB
Download this file (qprobe-front.zip)qprobe-front.zip[Gerber files for LED front panel]11 kB
Download this file (qprobe-ledmask.stl)qprobe-ledmask.stl[LED body 3d print]612 kB
Download this file (QProbe-lowerleds-bender.stl)QProbe-lowerleds-bender.stl[Helper to bend lower LED pins 3D print]72 kB
Download this file (qprobe-top-pos.csv)qprobe-top-pos.csv[SMD positions JLCPCB. "CPL" = "Component Placement List"]3 kB
Download this file (qprobe.zip)qprobe.zip[Gerber files for main PCB]789 kB
Download this file (schematic.pdf)schematic.pdf[QProbe schematic]570 kB