SAM9G45 Atmel Corporation, SAM9G45 Datasheet - Page 920

• Manufacturer Part Number: SAM9G45
• Manufacturer: Atmel Corporation

Specifications of SAM9G45

• Flash (kbytes): 0 Kbytes
• Pin Count: 324
• Max. Operating Frequency: 400 MHz
• Cpu: ARM926
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 160
• Ext Interrupts: 160
• Usb Transceiver: 3
• Usb Speed: Hi-Speed
• Usb Interface: Host, Device
• Spi: 2
• Twi (i2c): 2
• Uart: 5
• Lin: 4
• Ssc: 2
• Ethernet: 1
• Sd / Emmc: 2
• Graphic Lcd: Yes
• Video Decoder: No
• Camera Interface: Yes
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 440
• Resistive Touch Screen: Yes
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 64
• Self Program Memory: NO
• External Bus Interface: 2
• Dram Memory: DDR2/LPDDR, SDRAM/LPSDR
• Nand Interface: Yes
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8/3.3
• Operating Voltage (vcc): 0.9 to 1.1
• Fpu: No
• Mpu / Mmu: No/Yes
• Timers: 6
• Output Compare Channels: 6
• Input Capture Channels: 6
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: No

40.7.4
920
SAM9G45
Pen Detect Method
When there is no contact, it is not necessary to perform conversion. However, it is important to
detect a contact by keeping the power consumption as low as possible.
The proposed implementation polarizes the vertical panel by closing the switch on X
the horizontal panel by an embedded resistor connected to Y
switch. Since there is no contact, no current is flowing and there is no related power consump-
tion. As soon as a contact occurs, a current is flowing in the touch screen and a schmitt trigger
detects the voltage in the resistor.
The Touch Screen Interrupt configuration is entered by programming the bit PENDET in the
“TSADCC Mode
tor are both closed, except when a touch screen conversion is in progress.
To complete the circuit, a programmable debouncer is placed at the output of the schmitt trigger.
This debouncer is programmable at 1 ADC Clock period, useful when the system is running at
Slow Clock, or at up to 2
Screen panel when the system is running at high speed. The debouncer length can be selected
by programming the field PENDBC in
Resistor
Resistor
Switch
Switch
X
X
VDDANA
M
P
GND
XPos Measure(Yp)
Rp
Register”. If this bit is written at 1, the switch on X
Open
circuit
Y
Y
P
15
M
ADC Clock periods, but better used to filter noise on the Touch
Resistor
Switch
“TSADCC Mode
X
X
M
P
GND
Z1 Measure(Xp)
Resistor
Switch
Rp
VDDANA
Open
circuit
Register”.
Y
Y
P
M
M
. This resistor is enabled by a fifth
X
X
M
P
P
Open
GND
and the switch on the resis-
circuit
Z2 Measure(Xp)
Resistor
Switch
Rp
6438G–ATARM–19-Apr-11
VDDANA
Y
Y
Resistor
P
M
Switch
P
and ties