User manual
SAM4E-EK User Guide
42067A−SAM4E−01/2013
17
4.3.14 Audio Interface
The Atmel SAM4E-EK evaluation kit supports mono/stereo audio driven by a TPA0223 audio amplifier connected to two
DAC channels of the microcontroller.
The TPA0223 is a 2W mono Bridge-Tied-Load (BTL) amplifier designed to drive speakers with as low as 4
impedance. The amplifier can be reconfigured on the fly to drive two stereo Single-Ended (SE) signals into head
phones.
Figure 4-14. Headphone output.
JP17
JP15
PB14
JP18
1
2
3
AUDIO_OUTL
JP14
1
2
3
J9
1
2
DAC0
R67 33K
J10
Phonejack Stereo 3.5
5
4
3
2
1
+
C62 220uF-TAN-6.3V
+
C58 220uF-TAN-6.3V
R64 1K
R63 1K
R71 47K
C65 0.47uF
AGND
AGND
AUDIO OUT
PB13
C59
1uF
C61
100nF
TP6
Test Pad SQ-40TH
R72 33K
C63 0.47uF
C67 0.47uF
MN8
TPA0223DGQ
VDD
3
RIN
5
MON O-I N
1
LIN
9
LO/MO-
10
RO/MO+
6
ST/MN
7
SHUTD0WN
2
BY PASS
4
GND
8
PAD
11
+
C60
10uF
C64 0.47uF
VDD_AMP
R70 100K
R68 100K R69 100K
AGND
AGND
AGND
AGND
VDD_AMP
C66
1uF
+5V
R65 33K
AGND
R66 47K
FB2
BN03K314S300R
+3V3
AGND
JP16
R73 0R
Using a readily available 1/8-in. (3.5mm) stereo headphone jack, the control switch (pin4 and pin5 in J10) is closed
when no plug is inserted. When closed, a 100k/1k divider pulls the ST/MN input low. When a jack plug is inserted,
the 1k resistor is disconnected and the ST/MN input is pulled high. The mono speaker (J9 connector) is also
physically disconnected from the RO/MO+ output so that no sound is heard from the speaker while the headphones are
inserted.
When works as stereo mode make sure JP15, JP16, and JP17 are disconnected.
4.3.15 USB device
The SAM4E16 UDP port is compliant with the Universal Serial Bus (USB) rev 2.0 Full Speed device specification. J11 is
a micro B-type receptacle for USB device.
Both 27 resistors R82 and R83 build up 90 differential impedance together with the (embedded) 6 output
impedance of the SAM4E16 full speed channel drivers.
R80 and R81 build up a divider bridge from VBUS +5V to implement plug-in detection (5V level gets lowered to a PIO
compatible 3.3V level) through PC21.