A dynamic bias system for burn-in or thermal endurance treatments of 8085 A microprocessors

A dynamic bias circuit has been developed for the 8085 A microprocessor, which uses a random number generator to produce an instruction sequence and to exercise the control functions during periods of burn-in or accelerated life testing. Advantages include a complete instruction set executed with equal frequency, all registers and pointers cycled through all possible values, and all control functions exercised with all combinations of interrupt mask settings and enable-interrupt control. The control system is readily adapted to control the exercise sequence for other large scale integrated components, including general purpose input-output controllers and universal serial receiver-transmitter controllers, using random data where appropriate and predefined patterns when necessary.