Using the AT89RFD-08 Board
AT89RFD-08 Hardware User Guide
2-7
4382E–MP3–05/06
2.2
Power Supply
The power supply input is performed through the SIP2 connector J1 on top of the board.
Figure 2-2.
Power supply connector
Once the power is established, the power LED (POWER-ON) is lit.
The on-board power supply circuitry allows various power supply configurations. The
power supply selection is performed using J14 jumper.
Figure 2-3.
Power Supply Input Configuration
To prevent malfunction due to insufficient power supply voltage, we assume that an
external brown-out protection or the Master system controls the AT89C51SND2C Reset
PIN.
Note:
Refer to Atmel Document ‘External Brown-out Protection for C51 Microcontrollers with
Active High Reset Input’, available on the Atmel web site.
2.2.1
5V to 9V power
Supply
J14 shall be configured in the opened position to allow regulation of the power supply to
a stable 3V voltage.
Table 2-1.
Regulated Power Supply Configuration
The power supply voltage is regulated with on board circuitry. Input voltage on this con-
nector should be included between 5 and 9V. This power supply input is protected
against polarization inversion.
2.2.2
3V power Supply
The direct power supply input can be used when J14 jumper is set closed. This input is
used to directly power the board without using the on-board regulator.
Power supply source
J14(*)
Min
Max
Unit
External Power Supply
opened
5
9
V