Hardware Description
2-5 C51 Microcontrollers Demo Board User Guide
4119C–8051–3/03
2.4 Board Supply Considerations
nPower connector J1 or battery connector J2 may be used to power the board.
nOn J2 connector a rechargeable battery or a non-rechargeable battery may b e used.
nIn case of rechargeable battery usage on J2, if J18 is ON the battery is charged when
the board is powered by J1.
nBoard 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