Agilent Technologies E2259A, User'S Manual And Programming Manual, Page: 26 / 52

Using the Breadboard 23
Using the Read
Decoder Lines
Expanding input registers with read decoder lines RP0-RP7 is similar to
expanding output registers (see Figure 2-2 on Page 21), except that a buffer
(74245) is used as an input buffer, RPn is used as a buffer enable signal, data
direction is toward MD15-MD0. The RPn lines can be used as select lines
to specify which device the data is read from. Figure 2-3 also shows the
timing of the RPn pulse. Table 2-3 lists the Read/Write Decoder Register
Addresses and the corresponding WP and RP lines.
Table 2-3. Read/Write Decoder Lines and Register Addresses
WP / RP Line Register Address WP / RP Line Register Address
WP0/ RP0 20
h
in A24 Memory WP4 / RP4 28
h
in A24 Memory
WP1 / RP1 22
h
in A24 Memory WP5 / RP5 2A
h
in A24 Memory
WP2 / RP2 24
h
in A24 Memory WP6 / RP6 2C
h
in A24 Memory
WP3 / RP3 26
h
in A24 Memory WP7 / RP7 2E
h
in A24 Memory