Using the AT85DVK-07 Board
AT85DVK-07 Development Board User Guide
2-9
4391B–MP3–07/07
Figure 2-6.
Low Voltage Application Power Configuration
Notes:
1. Option to allow power key-press detection by the AT85C51SND3Bx.
2. Option to allow battery voltage monitoring by the AT85C51SND3Bx.
2.2.5
External DC-DC
Replacement
In order to allow developers to validate other external DC-DC power supply solution, two
extension connectors J19 and J22 (see Table 2-6 and Table 2-7) are provided as option
to plug a daughter board featuring an external 3V low voltage DC-DC.
In such configuration the board must be configured in “Low Voltage” mode and SE38
along with SE56 must be open.
Table 2-6.
External DC-DC Extension Connector (J19)
Table 2-7.
External DC-DC Extension Connector (J22)
2.3
Microcontroller
Unit
The Microcontroller unit consists in the AT85C51SND3Bx component in LQFP100 pin
package including its 12 MHz oscillator and the reset (RST) and in system programming
(ISP) push-buttons.
S
E
3
5
AAA Battery
S
E
3
3
S
E
3
2
S
E
3
4
S
E
5
6
SE57
(1)
SE58
L5
Socket
Bottom View
Top View
SE38
S
E
3
7
(2
)
J20
Pin Number
Pin Name
Pin Description
1
VBAT
Direct battery supply voltage
2
EXTDC
Battery supply voltage (SE38 ON)
3
P3.4/EXTDC_ON
Asserted low permanent power-on signal
4
SW_ON
Active low power-on switch
Pin Number
Pin Name
Pin Description
1
VBUS
USB +5V supply voltage
2
HVDD
3V supply voltage
3
LVDD
1.8V supply voltage
4
VSS
0V digital supply reference
