In-Circuit EPROM Programming Interface
Original Publication Date: 1983-Sep-01
Included in the Prior Art Database: 2005-Feb-07
Eraseable programmable read only memory (EPROM) 10 can be erased and rewritten using an EPROM burner 20 under program control of microprocessor 30. Microprocessor 30 controls the interface circuit of Fig. 2 by providing a mode select signal on line 51 to set up a program mode for writing or a read mode. In program mode, 25 volts on line 52 are applied via module 55 to line 56 leading to the EPROM. The write control line 61 from module 60 is rendered active by microprocessor 30 which applies a card select signal and a memory write signal to AND 70. Microprocessor 30 provides the appropriate address and data to the EPROM via tri-state drivers 80 and 85, respectively. When writing the data to the EPROM module, the control, address and data lines must be held in steady-state condition for approximately 50 milliseconds.