User manual

SAM4E-EK User Guide
42067A−SAM4E−01/2013
18
Figure 4-15. USB.
C75
10pF
R83 27R
RV1
V5.5MLA0603
PC21
FGND
PB10
RV2
V5.5MLA0603
USB
5V D- D+ ID G
J11
TBD USB Micro B
1 2 3 4
7
5
6
8
9
10 11
R81 68K
R80 47K
FGND
R82 27R
PB11
4.3.16 Analog interface
4.3.16.1
Analog reference
The 3.0V voltage reference is based on a LM4040 (Precision Micropower Shunt Voltage Reference).
This ADVREF level can be set as 3.0V or 3.3V via the jumper JP3.
Figure 4-16. Analog Vref.
R1
2.2K
+5V
MN 1
LM4040AIM3X-3.0
+3V3
C14
1uF
C13
100nF
ADVREF
JP3
1
2
3
4.3.16.2 Analog input
• The BNC connector CN2 is connected to the AEF0_AD4 or AFE1_AD0 (selected by JP40) as a single external
analog input
• The BNC connectors CN3, CN4 are connected to AFE0_AD10 and AFE0_AD11 as a differential external
analog input. A low pass filter is optional by close 1-2 pins of JP21, JP22, JP24, and JP25
• Each BNC input has an on-board 50 resistor termination that can be applied by closing jumper JP20, JP23 or
JP26
• A 10k potentiometer (VR1) is also connected to the AFE0_AD5 implement an easy access to ADC
programming and debugging (or implement an analog user control like display brightness, volume, etc.)