Tektronix Webcam 070-8030-01 User Manual

Page of 652
Theory of Operation
1780R-Series Service Manual
3–49
Diagram 18 Line Rate Controller
The Line Rate Controller provides real time control of the readout and line select
functions for both the waveform monitor and vectorscope CRTs. It issues
instructions to start, stop, hold, or skip readout. It determines if only readout is to
be displayed, readout is to be sent in block or burst form with a return to video
display, or if a sequence of two lines of video followed by two lines of readout
will be executed.
The Line Rate Controller sequentially executes a stack just as a state machine
does. The stack consists of 4-byte blocks of TaskData. TaskData consists of two
bytes representing the video line number and two bytes to be sent to the Readout
Engine and Z-Axis. The Line Rate Controller receives TaskData information
from the Master MPU over the Internal Data (ID) Bus. The data is stored in the
static RAM. There are two stacks in RAM, one that contains the TaskData that is
Overview