Milkymist One RC2 Known Issues
From Qi-Hardware
Here is the known issues found during debugging and testing RC2
Contents |
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: 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
- 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 for GND on top copper with circular mask to easily do some scopes.
- Add test point for DONE, PROGRAM_B and RP# pin.
- 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.
- Placement MK1 to be more precisely.
- Let J11 DC Jack footprint tighten to its body for better mechanical match later.
- 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
