VDP 313xY
ADVANCE INFORMATION
In each field two sets of measurements can be taken:
2.11.2.SCART Output Signal
a) The picture tube measurement returns results for
The RGB output of the VDP 313xY can also be used
to drive a SCART output. In the case of the SCART
signal, the parameter CLMPR (clamping reference)
has to be set to 1. Then, during blanking, the RGB out-
puts are automatically set to 50 % of the maximum
brightness. The DC offset values can be adjusted with
the cutoff parameters CR, CG, and CB. The amplitudes
can be adjusted with the drive parameters WDR,
WDG, and WDB.
– cutoff R
– cutoff G
– cutoff B
– whitedrive R or G or B (sequentially)
b) The picture measurement returns data on
– active picture maximum current
– active picture minimum current
tube measurement
picture meas. start
The tube measurement is automatically started when
the cutoff blue result register is read. Cutoff control for
RGB requires one field only while a complete whit-
edrive control requires three fields. If the measurement
mode is set to ‘offset check’, a measurement cycle is
run with the cutoff/whitedrive signals set to zero. This
allows to compensate the MADC offset as well as the
input the leakage currents. During cutoff and whit-
edrive measurements, the average beam current lim-
iter function (see Section 2.11.3. on page 23) is
switched off and a programmable value is used for the
brightness setting. The start line of the tube measure-
ment can be programmed via I2C-bus, the first line
used for the measurement, i.e. measurement of cutoff
red, is 2 lines after the programmed start line.
active video
field 1/ 2
picture meas. end
small window for tube
measurement (cutoff, whitedrive)
large window for active picture
picture meas. start
Fig. 2–19: Windows for tube and picture measure-
The picture measurement must be enabled by the con-
trol microprocessor after reading the min./max. result
registers. If a ‘1’ is written into bit 2 in subaddress 25,
the measurement runs for one field. For the next mea-
surement a ‘1’ has to be written again. The measure-
ment is always started at the beginning of active video.
ments
The vertical timing for the picture measurement is pro-
grammable, and may even be a single line. Also the
signal bandwidth is switchable for the picture measure-
ment.
Two horizontal windows are available for the picture
measurement. The large window is active for the entire
active line. Tube measurement is always carried out
with the small window. Measurement windows for pic-
ture and tube measurement are shown in Fig. 2–19.
22
Micronas
MICRONAS [ MICRONAS ]
