Toshiba TMP91C815F Data Book page 68

(4) Port 73 (/CS2F),74(/CS2G),75(/CSEXA)
Port73 to 75 are general-purpose I/O ports. These are also used as control signal for extend
chip-select output.
Reset
Function
control 2
(on bit basis)
P7FC2 write
Direction
control
(on bit basis)
P7CR write
Funtcion
control
(on bit basis)
P7FC write
S
Output latch
P7 write
/CS2F,/CS2G,/CSEXA
P7 read
S
A
Selector
B
S
B
Selector
A
Figure 3.5.15 Port 73,74,75
91C815-65
TMP91C815
P73(/CS2F),
P74(/CS2G),
P75(/CSEXA)