Chapter 2—Functional Descriptions
2-38
Model 330. 340SC, and 370SC Service Manual
Table 2-8
VDB Serial Bus Information
Bus
I/O
Information
Description
IIC
O
Front/Rear convergence
indication
TTL level that indicates whether the X-
convergence is in front screen mode (high)
or rear screen (pulled low).
IIC
I
Serial data load
Command to the serial data receiver that the
incoming data is to be read.
Serial
I
VH
Commanded vertical height of picture.
Serial
I
VCENTBLU
Commanded vertical position of blue raster.
Serial
I
VCENTGRN
Commanded vertical position of green raster.
Serial
I
VCENTRED
Commanded vertical position of red raster.
Serial
I
TRAPCORR
Commanded L/R keystone correction.
Serial
I
LRPNCORR
Commanded L/R pincushion correction.
Serial
I
TBPNCORR
Commanded T/B pincushion correction.
Serial
I
HLINCORR
Commanded overall horizontal linearity
correction.
General I/O
This section provides a comprehensive description of the inputs to and outputs from the
VDB. The I/O description are arranged by the source/destination of the signal and so the
assemblies communicated with are used as the primary heading of each group of signals
and then are further subdivided into inputs and outputs. In each case, the signal's direction
is noted, with input referring to an input to the RTG, and output to an output from the
VDB. (e.g. under 'Raster Timing Generator', 'Input'; /PCST refers to the signal /PCST that
is an input to the VDB from the Raster Timing Generator). When test points are provided
for the I/O they are noted.
Table 2-9
Vertical Deflection Board I/O Signals
System Controller Board
Input
Description
IICCLK
IIC clock line. Unidirectional clock line for control of synchronous data
transfer over IIC data bus.
RXCORR
A 0-1 V signal from the bit-mapped memory on the SCB. 0.5V represents
no correction. This is a real time signal representing the X correction on
red.
RYCORR
Similar to RXCORR.
GXCORR
Similar to RXCORR.
GYCORR
Similar to RXCORR.
BXCORR
Similar to RXCORR.
BYCORR
Similar to RXCORR.
+SERCLK
Serial data transfer clock (+). Unidirectional, differential clock line from
SCB to other circuit boards. Used for synchronous control of serial
communication over SERDATA data lines.
-SERCLK
Serial data transfer clock (-).