Dual method of configuring Altera 10K family PLDS

A dual method of configuring programmable logic devices from the Altera FLEX 10K family is presented. A passive serial configuration is employed with the programming object files transferred from an onboard EPROM. The second source, selectable with a switch, is an external PC via a BitBlaster connection. Presently, Altera has no recommendation for a switchable source of programming files. The scheme presented has been tested on several configurations of single and multiple daisy-chained devices. This method enables field programmability together with EPROM power-up configuration for 10K devices. It proved to be a valuable tool during the debugging stage.