Milkymist One RC2 Known Issues

Here is the known issues found during debugging and testing RC2

Joerg's feedback

• insert fuse between powerjack and first capacitor (see above). Add a diode parallel to first capacitor, to short inverse polarity and make fuse trip
• cut connection from J11,pin1 to C142. Insert a 2A fuse slowblow
• make L7 L8 L9 L10 L12 L20 0R (those L that are in regulator outputs together with the 100nF Cs)
• the C's nearby are cruft then, one of two, as well
• but don't hurt, so you might consider removing one of two, and make the other 200nF, for BOM reduction
• scratch R182 pads, looks dangerous

Notice: above info just for references though. We finally only added one PTC 2A fuse and two 5.6V Zener diodes. see more experimental results on Protection of Reversed Polarity on DC plug-in.

Major errors

• cannot boot after fast power cycling, need to ask Xilinx FAE.
• Sebastien posted "the video input on my mm1 (which was the one we did the ESD tests with) just broke down on me. it detects a SECAM 525 signal even when there's nothing connected, and the picture is always black no matter what you do, a P/N: V9MLA0402 will be placed on each video-in source.
• ADV7125 Ground Pins wrong connections.
• Production
  • parts swapped manually in wrong, must be R30 -- 4.7K ohm, R39 -- 330 ohm.
  • parts manually entered in wrong, must be R147/R148/R150 -- 4.7K ohm.
• BoM
  • change Y2 to other stronger package 49US(SMD) Crystal which is a fundamental mode and place it at top side.

Minor errors and improvements

These errors do not alter the functionality of the board.

• Schematic
  • Add bigger test point on top copper with circular mask to easily do some scopes.
    • 5V: TP33.
    • GND: TP34, one through hole header pin.
  • Add test points for DONE, PROGRAM_B and RP# pin.
    • DONE: TP35
    • PROGRAM_B: TP36
    • RP#: TP37
  • Add low voltage detector & diode to fix no-loaded standby bitstream from flash after power on.
  • Change h/w version control of resistor set.
• PCB design
  • Put one more via on U6 pin8 and U4/U5 Vcc pins.
  • Change Y2 to a different type like Y1.
  • Let J11 DC Jack footprint tighten to its body for better mechanical match later.
  • Slightly make "M" & "cc-by-sa" logo a bit bigger both sides. move text to some places a little.
  • silk screen: change "SW1" -> "SW_R", "SW2" -> "SW_ON", "SW3" -> "SW_L"
  • place MK1 microphone stays at board edge to face acrylic case and bend two pins in a 90 degree.
  • place C36 nearby C30.
• Materia
  • Incoming parts check: pins lifted? different mark?
• Production/SMT
  • Notice that even incoming parts are not good, try to use AOI and manually visual inspection to cover the poor, cool and crappy soldering.
• Testing
  • Use jtag-serial board for faster reflashing

Links

Milkymist One Power On Off Sequence

Protection of Reversed Polarity on DC plug-in