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Publication No. 980938 Rev. K
Model T940 User Manual
Astronics Test Systems
Functional Description 4-15
Pattern RAM
The output code as well as the input code for every channel of each pattern is
stored in the Pattern RAM.
Record RAM
This is where the individual channel results are stored. The channel results are
either the pattern input compare result or raw response data based on RH or RL.
The results can be stored in normal or indexed starting from address zero and
expanded.
Frequency Synthesizer
The Frequency Synthesizer (FS) may be used in lieu of the 500 MHz oscillator as
the master clock. The reference clock for the FS may be a built-in 20 MHz
oscillator, VXICLK10, LCLK100/2 or any of the AUX inputs in the range of 5 to 80
MHz.
Sequence Control
This block contains the registers and logic used to program the data sequencer.
Channel Control
This block takes the output code from the pattern RAM, formats it and outputs it
according to the phase timing (PHASE). The resultant drive (CH DATA) and
enable (CH EN) signals go to the Driver/Receiver logic.
The response high (CH RH) and response low (CH RL) signals from the
Receivers are examined, and then, based on the window timing (WINDOW), the
response is analyzed with respect to the input code. The channel results are
routed to the Record RAM. The cumulative Error signal goes to the Sequence
Logic block so it can be used for Jumping, Halting and the Counting of Errors.
Individual over-current (OC) signals from the Channel Drivers can also be
processed by this block to disable the channel drivers if desired.
AUX & Probe Control
AUX control allows user and diagnostic signals to be input or output the AUX
pins. The inputs go to the Sequence Logic block described above. There is also
a Multi-purpose signal (MPSIG) which can be combined with other signals on the
Driver/Receiver board and provided to the user on the power connector.
Probe expect data is received from the Probe/Flag RAM and result data is
generated that is stored back into the Probe/Flag RAM.