The 87C576 includes two separate methods of programming the
EPROM array, the traditional modified Quick-Pulse method, and a
new On-Board Programming technique (OBP).
Quick Pulse programming is a method using a number of device
pins in parallel (see Figure 1) and is the traditional way in which
87C51 family members have been programmed. The Quick-Pulse
method supports the following programming functions:
– program USER EPROM
– verify USER EPROM
– program KEY EPROM
– program security bits
– verify security bits
– read signature bytes
The Quick-Pulse method is quite easily suited to standard
programming equipment as evidenced by the numerous vendors of
87C51 compatible programmers on the market today. One
disadvantage is that this method is not well suited to programming in
the embedded application because of the large number of signal
lines that must be isolated from the application. In addition, parallel
signals from a programmer would need to be cabled to the
application’s circuit board, or the application circuit board would
need to have logic built-in to perform the programming functions.
These requirements have generally made in-circuit programming
using the modified Quick Pulse method impractical in almost all
87C51 family applications.