Atmel C51 - Manual (Page 8)

Hardware Description
2-5 C51 Microcontrollers Demo Board User Guide
4119C–8051–3/03
2.4 Board Supply
Considerations n
Power connector J1 or battery connector J2 may be used to power the board.
n
On J2 connector a rechargeable battery or a non-rechargeable battery may be used.
n
In case of rechargeable battery usage on J2, if J18 is ON the battery is charged when
the board is powered by J1.
n
Board may be powered by J2 for about 10 hours with one new non-rechargeable
battery.
Note: J18 must be Off, when the board is powered by J1 with a non-rechargeable
battery connected on J2 (see figure 3).
Figure 2-2. C51/C251 Demo Board powered by J1 with a non-rechargeable battery on J2
Figure 2-3. C51/C251 Demo Board powered by J1 with a rechargeable battery on J2
J1 Power Supply Connector
9V to 12V DC IN
J18
9V
PP3
J2
OFF
non-rechargeable
battery
AC-DC
LCD display
LCD display
J1 Power Supply Connector
9V to 12V DC IN
J18
9V
PP3
J2
ON
battery is being charged
In this configuration
rechargeable
battery
AC-DC