1.4 Reconfiguring the 7188XC(D)/7521(D)
From pin-4 to pin-8 of the 7188XC(D)/7521(D) there are three D/O &
two D/I pins. For the application of “Customized 7000 Modules”, these
5 D/I/O pins can be hardware reconfigured to other functions as
follows:
Step 1:
Remove the reconfiguration-resistor as follows:
If DO3 is reconfigured, remove R19
If DO2 is reconfigured, remove R20
If DO1 is reconfigured, remove R21
If DI3 is reconfigured, remove R22
If DI2 is reconfigured, remove R23
Then, the onboard D/I/O functions can be disabled.
Step 2:
Install a 5-pin male reconfiguration-jumper into the TP0 of the
7188XC(D)/7521(D)
Step 3:
Design a 5-pin female reconfiguration-jumper in X??? for
Connection to TP1. Then the external signals from pin-4 to
pin-8 can be connected to X???. The user can refigure these
5 D / I / O p i n s t o t h e i r s p e c i a l r e q u i r e m e n t s n o w .
Note:
If the DO2 is reconfigured to D/I, its initial state must be High. If
its initial state is LOW, system clock will be reduced to 10M. So
all clock-related libraries will only be at half-speed.
Refer to next page for more information.
I/O Expansion Bus for 7188X/7188E User’s Manual, Jan/2005 v1.5, 7PH-000-15---9