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7.1.2 WCKIO (Old CVS2In)
This connector can be used, under software control, in 2 modes: Wordclock IN or Wordclock OUT.
When software configured as a WCK Input it accepts an external Wordclock reference signal between 0.2 and 5 Vp-p. When
software configured as a WCK Output it provides a 5 V TTL-compatible signal with 22-Ohm output impedance.
Note:
whenever used with a Wordclock signal (either Input or Output), do not terminate (JP5 open) on Mykerinos and on the
Video/TC bracket (This is the default factory settings).
Note
, that historically, this connector was able to input a Video signal, as well. The following modification has been made,
dated from November 2004:
The Video input feature has been removed from CVS2In/WCK signal
.
The Wordclock I/O
capability remains unchanged
. This modification applies to the following Mykerinos boards: MB1 S/N 12600 - … and
MB5 S/N 16150-16759 and 16803 - ….
See below an extract of the ECO MYK011B for a technical detailed explanation:
“
When too high a voltage is applied to the Video 2 input (CVS2IN-WCKI/O), the Video sub-system of the Mykerinos card may enter into an
unstable state (latch up) and subsequently corrupt the proper decoding of the Video 1 Input signal (CVS1IN) as well as the Video Output
signal (CVSOUT). This is specifically the case when CVS2IN is used as a word clock I/O. The Video/TC handling sub-unit on the
Mykerinos card may be triggered to enter this latch-up state with as little as a full 5 Volt p-p Wordclock signal applied.
To resolve this issue permanently, the solution is to physically remove the path linking the CVS2IN-WCKI/O to the Video/TC circuitry and
disconnect this input from the Video sub-system by removing the C127 capacitor to prevent any signal to enter into the Time code chip
(U10). This modification does not prevent to use the Word clock I/O feature but removes the possibility to use the CVS2IN-WCKI/O as a
secondary Video/VITC input
”
7.1.3 CVS OUT
This signal outputs the composite video signal coming from CVS1IN only. This signal may additionally carry a VITC and/or
a time code "burn-in" video insert generated by Mykerinos.
Note
: CVSOUT provides a monitoring quality video output only and is not intended to be used as a loop through “black
burst” output.
7.1.4 LTC IN
LTC IN is a symmetrical input signal. It accepts an external SMPTE/EBU time code signal between 0.2 and 5 Vp-p.
7.1.5 LTC OUT
LTC OUT is an unbalanced output signal. The output voltage level can be software adjusted from 0V to 2.5V p-p.
