AT91SAM9G45-CU-999 Atmel, AT91SAM9G45-CU-999 Datasheet - Page 942

• Manufacturer Part Number: AT91SAM9G45-CU-999
• Description: IC MCU ARM9 APMC 324TFBGA
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM9G45-CU-999

• Core Processor: ARM9
• Core Size: 16/32-Bit
• Speed: 400MHz
• Connectivity: EBI/EMI, Ethernet, I²C, IrDA, MMC, SPI, SSC, UART/USART, USB
• Peripherals: AC'97, DMA, I²S, LCD, POR, PWM, WDT
• Number Of I /o: 160
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: ROM
• Ram Size: 128K x 8
• Voltage - Supply (vcc/vdd): 0.9 V ~ 1.1 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 324-TFBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Supplier Unconfirmed

40.7.4
942
AT91SAM9G45
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
6438F–ATARM–21-Jun-10
VDDANA
Y
Y
Resistor
P
M
Switch
P
and ties