Hi,
here is the change list:
* Connect P[15:8] instead of P[7:0] on the video decoder chip U21
OK, and no change on FPGA pin assignment
* The installed IR detectors do not work. This is not a PCB problem
and it can be solved by replacing the IR detector module with one
from another source.
N/A
* The MIDI optoisolator is not suitable. Replace it with a
6N138S/6N138_X007 and lower R54 to 120 ohms. Connect pin 8 to
3.3V and leave pin 7 unconnected.
Your Altium schematics symbol is not correct, the pins must be turned
the other way around (with the numbers inside the case and the
connections on the opposite end). Also, please indicate the pin names
for better readability of the schematics.
OK for R54.
* For USB to work reliably, 15K pull down resistors must be
installed on the D+ and D- lines of each USB port (between the 24
ohm resistors and the ports). Add the possibility to make them
pull-up resistors to 3.3V (i.e. add placeholders for pull-ups) so
the USB ports could work in device mode with a small PCB
modification.
OK
* Add 1K pull-down resistor on ETH_RESET_N (specification says
reset should be low during power-up)
OK
* Add 1K pull-down resistor on VIDEOIN_RESET_N (the application
schematics includes external POR circuitry)
OK
* Add notch to mark pin 1 of J3 on silkscreen
N/A
* Use red, green and blue connectors for J18
N/A
* We might want a larger soldered area under the pads of U10
N/A
* Indicate "+/- 5%" and pinout (positive in the middle) near J11 on
silkscreen
N/A
* Add a 5V supply pin on the GPIO expansion header
OK
* Add a test point at the output of the MIDI optoisolator
OK
* Add test points on the USB signals (3.3V FPGA side: VP, VM, RCV,
OE)
OK
* To reduce audio output noise, power the LM4550 analog supply
through an additional TPS76301 set to 4.3V.
OK, chosen resistor values produce a nominal voltage of 4.29V, which is
sufficiently above the 4.2V limit of the LM4550.
* In order to be able to detect board revisions, route 4 FPGA I/O
pins to placeholders for 0402 pull-up resistors. The combination
of placed and non-placed resistors encodes the board revision.
The RC2 board should be encoded as 0001 (ie place only 1
resistor) to distinguish it from RC1 which does not have any
resistor. Use 1K resistors for pull-ups.
OK, HW_VER_0..3 connected to FPGA pins AA10, AB10, Y10 and Y12 (in this
order)
* Improve power supply immunity:
To be done...
Regards,
S.
Le Fri, 24 Sep 2010 15:46:44 +0800,
Adam Wang <[email protected]> a écrit :
> Hi,
>
> Current RC2 schematics (not final) are in progress, you can check it
> here [1].
> The schematics have changed according to [2] except Improving power
> supply
> immunity<http://www.milkymist.org/wiki/index.php?title=RC1_signal_integrity_measurements>
> .
> Next steps will start to route and change remaining items
> simultaneously. While this stage is moving, pls kindly provide any
> comments.
>
> [1]
> http://downloads.qi-hardware.com/hardware/milkymist_one/pcb/rc2/092410/rc2_design.tar.bz2
> [2] http://www.milkymist.org/wiki/index.php?title=RC1_errata
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