Pico Systems

General Timing and Logic Module

The General Timing and Logic Module is a double-width CAMAC module which uses Xilinx programmable logic chips to implement both the logic and timing functions for an entire experimental setup. It has 10 NIM inputs and 8 NIM outputs. The NIM outputs can be used interactively for debugging and setup, or several outputs can be dedicated to provide triggers or gating conditions to other equipment. There are also 24 differential ECL outputs, with individually adjustable delay and gate generators for each output. Every delay or gate generator can be adjusted from 25 nS to 15 uS by computer control. There are a total of 72 digitally-programmed delay circuits in the module. 48 of them are dedicated to delay and gate circuits on the 24 ECL outputs, the rest can be used in any combination with the standard logic functions provided in the Xilinx chips.

This unit is currently being used in field experiments with the MicroBall and GammaSphere at Argonne National Lab.

This unit has been set up to perform all timing, gating, and logic for the Washington University MicroBall detector, and coincidence with the GammaSphere acquisition logic.

The logic can be reprogrammed using a software package from Xilinx, the maker of the programmable logic chips. Although the software to download the logic programming information through the CAMAC bus has not yet been written, the hardware capability is designed into the module.

The unit is controlled through the CAMAC bus, and an interactive program that runs on a PC allows the user to adjust each delay while observing the related signals through the NIM outputs. Each of the 8 NIM outputs can be commanded to show any one of the delay signals or other interesting point in the logic.

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