Hardware Description
AT89C5131A Starter Kit Hardware User Guide
2-5
4245A–USB–11/04
2.3
C51 Standard
Settings
2.3.1
Reset
The external Reset push-button (SW3) is provided to easily generate a warm reset. This
button is used for ISP process. The Reset applied is active low.
2.3.2
Clock
A crystal can be easily installed on the Y1 socket. The clock can also be provided using
the J8 connector instead of the crystal.
Note:
Remove the clock generators before the using the programmer.
2.3.3
EA
Place a jumper on the EA connector (J10) to force the EA pin to ground and execute
external code. Otherwise internal code will be executed.
Figure 2-3. EA Circuitry
2.3.4
INT0
In order to use the on-board INT0 circuitry, connect the J7 Jumper to the AT89C5131A.
When you press the INT0 button (SW5), the P3.2 pin will go low which induces an inter-
rupt event.
Note:
Remove the J7 jumper before using the programmer. Otherwise the program-
mer will not function.
Figure 2-4. INT0 Circuitry
