28301 Parallax Inc, 28301 Datasheet - Page 6

• Manufacturer Part Number: 28301
• Description: DAUGHTERBOARD 3PIN I/O MOBO
• Manufacturer: Parallax Inc

Specifications of 28301

• Accessory Type: Daughter Board, Power and I/O Interface
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: MoBoStamp, MoBoProp
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Absolute accuracy is deemed “poor” if the AVR’s voltage reference is unregulated; “good”, otherwise.
Ratiometric accuracy is deemed “poor” if the source reference and AVR reference are different, and at
least one of them is unregulated; “fair”, if the two references are different, but both are regulated;
“good”, if both references are the same, whether regulated or not.
The following illustrations show how a potentiometer can be connected as an analog input device to the
PWR-I/O-DB:
© Parallax, Inc. • PWR-I/O-DB (2006.09.13)
J1 6-9VDC
DB
5V
DB
MB
“Reg” stands for “regulator”; “Int” , for “internal”.
* Use a divider to divide fullscale output to 1.1V. Voltages above 1.1V will read as $3FF.
† Input voltage must not exceed 3.3V . Use a divider to divide fullscale output to 3.3V, or
use a series current-limiting resistor to limit voltages above 3.3V to 3.3V at the AVR’s input.
A1 A0 A3 A2 P8 P9
MB
USB/EXT
USB
EXT
USB
EXT
DB 5V MB
Vin J1
Vdd = 5V
MB
5V/3.3V
5V
3.3V
5V
3.3V
5V
3.3V
5V
3.3V
10K Linear Pot.
Source Ref
DB 5V Reg
DB 5V Reg
DB 5V Reg
DB 5V Reg
DB 5V Reg
DB 5V Reg
DB 5V Reg
DB 5V Reg
USB 5V
USB 5V
USB 5V
USB 5V
MB 5V Reg
MB 5V Reg
MB 5V Reg
MB 5V Reg
AVR’s Ref
Vdd (USB 5V)
Int 1.1V Ref
Vdd (MB 3.3V Reg)
Int 1.1V Ref
Vdd (MB 5V Reg)
Int 1.1V Ref
Vdd (MB 3.3V Reg)
Int 1.1V Ref
Vdd (USB 5V)
Int 1.1V Ref
Vdd (MB 3.3V Reg)
Int 1.1V Ref
Vdd (MB 5V Reg)
Int 1.1V Ref
Vdd (MB 3.3V Reg)
Int 1.1V Ref
J1 6-9VD C
A1 A0 A3 A2 P8 P 9
DB 5V MB
Vin J1
Vdd = 3.3V
Absolute
Accuracy
Poor
Good *
Good †
Good *†
Good
Good *
Good †
Good *†
Poor
Good *
Good †
Good *†
Good
Good *
Good †
Good *†
5.1K Resistor
10K Linear Pot.
Ratiometric
Accuracy
Poor
Fair *
Fair †
Fair *†
Fair
Fair *
Fair †
Fair *†
Good
Poor *
Poor †
Poor *†
Good
Fair *
Fair †
Fair *†
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