Question 16.15: How will you program a PROM?...

A PROM is normally programmed by plugging it into a special instrument called a PROM programmer. Basically, the programming is accomplished as shown by the simplified set up in Fig. 16.12.

An address is selected by the switch setting on the address lines, and then a pulse is applied to those output lines corresponding to bit locations where 0 ‘s are to be stored (the PROM starts out with all l’s). These pulses blow the fuse links, thus creating the desired bit pattern. The next address is then selected and the process is repeated. This sequence is done automatically by the PROM programmer.