readme update

pull/3/head
davor 7 years ago
parent ac8a91e1c1
commit 29f7e10ba6

@ -49,16 +49,6 @@ run its games, but can do much more.
kicad ulx3s.pro
[PCB v1.7](/pic/ulx3st-real.jpg) is produced. For this board to work,
IPC CLASS 3 quality PCB is required, 5/5 mil resolution and 0.2 mm holes.
Important board features are tested and work like
USB-JTAG, SDRAM, SDCARD, HDMI, FLASH, RTC, I2C, OLED, AUDIO, ADC, 433.92MHz
US2 can be used to plug USB-PS/2 combo keyboard but US2 feature as USB
host/device is not tested.
There are known issues, luckily most can be fixed by
[Upgrading PCB v1.7](/doc/pcb-v1.7-upgrade.md).
# Features
FPGA: Lattice ECP5 LFE5U-85F-6BG381C
@ -93,12 +83,41 @@ Clock: 25 MHz onboard, external differential clock input
Low power sleep: RTC clock wakeup, power button, 32768 Hz quartz and battery
GPDI is General Purpose Differential Interface,
Electrically LVDS, mostly TMDS tolerant
female receptacle more-or-less compatible
with digital monitors/TVs
# Production
If you are going to order this project by yourself, it is important
what manufacturer to choose for PCBA (PCB and Assembly) service.
Choose PCBA manufacturer which can produce PCB of IPC CLASS 3 quality,
5/5 mil trace resolution and 0.2 mm holes.
Avoid manufacturer who claims "quality" and "satisfaction" but doesn't
really know what will be IPC CLASS rating for this project.
PCBA manufacturer prices for the parts should be approximately equal as those
from distributors like [Mouser](www.mouser.com) or [DigiKey](www.digikey.com).
Avoid any PCBA manufacturer who asks 3$ for the 1$ part or 40$ for the 30$ part.
Select [Mouser](www.mouser.com) language/location icon to PCBA manufacturer
country of origin and $-currency to check is PCBA manufacturer telling the truth
about prices.
[PCBWAY](www.pcbway.com) produced [ULX3S v1.7 45F](/pic/ulx3sb-v17.jpg) in
December 2017 at above of CLASS 3 quality, $126 per board.
[PCBWAY](www.pcbway.com) produced [ULX3S v1.8 85F](/pic/ulx3sb-v18.jpg) in
May 2018 at the edge of CLASS 1 quality acceptance
(drill randomness and copper layer misaligment, hole breakout about 180°),
$134 per board.
[PCBWAY](www.pcbway.com) is cheap at boards and assembly but asks
$40 for FPGA 85F chip which costs $30 at [Mouser](www.mouser.com).
[PCBCART](www.pcbcart.com) would be my next choice because they
offer CLASS 3 quality and assembly at reasonable cost. Prices for the
parts are equal as from [Mouser](www.mouser.com) so total price per
board should be about the same as above.
# Todo

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