A microcomputer-controlled multichannel programmable pattern generator

The design of a single-board, microcomputer-controlled, digital pattern generator is discussed. The generator provides eight synchronous, TTL-compatible, NRZ channels. The controller is a 6502-based Rockwell AIM 65 microcomputer. The generator master clock frequency is 10 MHz, but a single vector can be delayed from 100 ns to 99000 s. Programmable delays avoid wasting memory in applications requiring short bursts of data followed by long steady-state conditions. Memory depth per channel is 100. The operational speed of the generator is independent of that of the controller. An interactive menu-driven program supports entry and editing of vectors for the sequence. After the sequence is transferred to the generator board, the generator can be started or reset locally, or by remote action. The generator can be configured in the burst or continuous modes. Features of the design are simplicity, low cost, flexibility for expansion of the number of channels and memory depth per channel, conversion into an arbitrary waveform generator, application as a square-wave function generator from 5 μHz to 5 MHz with programmable duty cycle, and seven supporting channels for trigger. The generator has been applied in the characterization of nonvolatile semiconductor memory transistors.