Hardware Description
C51 Microcontrollers Demo Board User Guide 2-6
4119C–8051–3/03
Figure 2-4. C51/C251 Demo Board Powered by J2.
2.5 Board Layout nOn-Off
–Switches ON the power supply.
nReset
–Resets the microcontrollers.
nINT1#
–Issues an interruption on microcontollers on INT1# pin.
nJ8 Connector
–Configure hardware in Page Mode or Non Page Mode.
–for C251 microcontrollers. For C51 products, the configuration must be set to
Non Page Mode.
nSynchro IN
–Used to connect several C51/C251 Demo Boards together, provides global
reset / interrupt for all connected C51/C251 Demo Boards.
nSynchro OUT
–Only one power supply is needed but it may be able to deliver enough
current to supply all the C51/C251 Demo Boards.
–There are no rules to connect two boards together anyone of the two DB9
may be used.
nRS232
–Used to connect a terminal or through an RS232 serial communication port.
–This serial port can be used for displaying messages or for program ming
external Flash memory.
Note: The cable that connect this RS232 Connector MUST be a pin to pin cable.
J18
ON
J1 Power Supply Connector
9V
PP3
J2
battery
NOT USED
(rechargeable or not)