Linear Technology DC890B, Быстрый старт, Страница: 5 / 13

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 890B
FastDAACS
5
CIRCUIT DETAILS
A schematic, parts list and parts placement drawings
are attached to the end of this Quick Start Guide for
reference only.
TROUBLE SHOOTING GUIDE
Problem: DC890B is plugged in, but QuickEval-II
software still does not recognize DC890B board.
Solution: Assuming that the USB hardware in your
computer is operational (Try verifying an operational
USB port with another USB device such as a USB
Memory stick, printer or scanner if available.), the
likely cause is improper installation of the USB driv-
ers, which results in Windows recognizing the
DC890B
as an “Unknown Device”. If this is the
case, the problem can be corrected by the following
procedure:
1) Unplug the DC890B board from the USB port.
2) Re-install the QuickEval-II Software.
CAREFULLY following the on-screen instruc-
tions. This MAY require a reboot of your com-
puter. The on-screen instructions will inform you
if that is the case.
3) If the problem persists, please choose
“Contact
Software Support” from the Tools Menu for as-
sistance from LTC staff.
Problem: Demonstration circuit software loads
properly, but will not run or gives “Device Not Ac-
cessible” errors.
Solution: Verify the demonstration circuit is prop-
erly powered up and a correct (signal level and fre-
quency) conversion clock is applied. (The DC890B
can operate from the USB port power in CMOS
mode but will not load the FPGA with the LVDS
code unless external power is detected.) Set the cor-
rect sample rate for the applied conversion clock as
QuickEval-II software uses the sample size and rate
to determine the watch dog time out period to reset
the DC890B if the USB bus should hang. Refer to
the appropriate demonstration circuit Quick Start
Guide for details.
Problem: Collected data samples look like noise or
appear corrupted.
Solution: Make sure the proper device has been se-
lected in the QuickEval-II software, the factory
jumper settings are present and for LVDS output
demo boards, external power is applied to the
DC890B otherwise the captured data will not be
properly interpreted.
Problem : QuickEval-II reports it cannot reset the
DC890B.
Solution : Make sure either a powered USB port is
used or external power is supplied. DO NOT USE A
USB CABLE LONGER THAN 2 METERS . The
time delay of a longer USB cable may result in the
DC890B intercepting the reset.
Problem : USB Bus appears to be hung.
Solution : As the DC890B is used in a lab environ-
ment where power may be inappropriately se-
quenced, cables unintentionally disconnected etc,
some users have reportedly had their USB bus hang.
This condition is easily rectified by right clicking
properties under my computer -> Hardware -> De-
vice Manager -> and then right clicking on the ap-
propriate USB bus controller and again selecting
properties. The device status generally reports that it
is working properly. Select the Advanced tab. You
will notice a refresh button. Device manager has
queried the port and as a result reset the bus.
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