Touch Screen Interface; Jtag/Ice - Atmel SAM4E-EK User Manual

4.3.12 Touch screen interface

The LCD module integrates a 4-wire touch panel controlled by MN16 (ADS7843) which is a slave device on the
SAM4E16 SPI bus. The controller sends back the measurement information about the X and Y positions as a pressure
is applied to the touch panel. The touch panel can be used with either a stylus or a finger.
The ADS7843 touch panel controller connects to the SPI interface via the NPCS0 control signal. Two interrupt signals
are connected and provide events information back to the microcontroller: PenIrq and Busy.
PenIrq (PA16) is shared with ZigBee signal ZIGB_MISC.
Note:
Busy (PA17) is shared with ZigBee signal ZIGB_IRQ.
Therefore, if using a ZigBee interface in concurrence with the Touch Screen controller, take care not to have both
drivers enabled at the same time on either PA16 or PA17.
Figure 4-12. Touch panel control.
2
X_RIGHT
3
Y _UP
4
X_LEFT
5
Y _DOWN
TP2 TP3
7
8
R27 R28
100K 100K
LCD TOUCH SCREEN
AGND_TP

4.3.13 JTAG/ICE

A standard 20-pin JTAG/ICE connector is implemented on the Atmel SAM4E-EK for the connection of a compatible
ARM JTAG emulator interface, such as the SAM-ICE™ from Segger.
Note that the NRST signal is connected to BP1 system button and is also used to reset the LCD module. The 0Ω
resistor R61 may be removed in order to isolate the JTAG port from this system reset signal.
Figure 4-13. JTAG interface.
R53
100K
PB4
PB6
PB7
PB5
NRST
+3V3
MN16
ADS7843E
16
PA14
XP DCLK
14
PA13
Y P DIN
12
PA12
XM DOUT
15
Y M CS
13
R22
BUSY
11
PENIRQ
9
R25
VREF
1
IN3 VCC1
10
IN4 VCC2
C39
6
100nF
GND
R54 R55 R56 R57
100K 100K 100K 100K
R61 0R
R19
100K
+3V3
JP9
R21
PA11
100K
PA17
0R R23 0R
0R
10uH-150mA
L2
R26
1R
C40 C41
100nF 100nF
C42
4.7uF
AGND_TP
ICE INTERFACE
+3V3
J8
HE10 20PTS
1
VTref Vsupply
3
nTRST GND1
5
TDI GND2
7
TMS GND3
9
TCK GND4
11
RTCK GND5
13
TDO GND6
15
nSRST GND7
17
DBGRQ GND8
19
DBGACK GND9
PA16
+3V3
R29
0R
2
4
6
8
10
12
14
16
18
20
SAM4E-EK User Guide
42067B−SAM4E−04/2013
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