AT91SAM9M10-G45-EK Atmel, AT91SAM9M10-G45-EK Datasheet - Page 936

• Manufacturer Part Number: AT91SAM9M10-G45-EK
• Description: KIT EVAL FOR AT91SAMG45/9M10
• Manufacturer: Atmel
• Series: AT91SAM Smart ARMr
• Type: MCUr

Specifications of AT91SAM9M10-G45-EK

• Contents: Board, Cables, Power Supply
• Processor To Be Evaluated: AT91SAM9M10
• Processor Series: AT91SAM9
• Data Bus Width: 32 bit
• Interface Type: RS-232, Ethernet, USB, JTAG
• Operating Supply Voltage: 5 V
• Silicon Manufacturer: Atmel
• Core Architecture: AVR
• Kit Contents: Board
• Features: Two High Speed USB Hosts, LCD TFT Display
• Svhc: No SVHC (15-Dec-2010)
• Mcu Supported Families: AT91SAM9M10,
• Rohs Compliant: Yes
• For Use With/related Products: AT91SAM9M10
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 40-2. Touch Screen Position Measurement
40.7.2
936
AT91SAM9M10
Position Measurement Method
As shown in
bottom. Due to the linear resistance of the film, there is a voltage gradient from top to bottom.
When a contact is performed on the screen, the voltage propagates at the point the two surfaces
come into contact with the second film. If the input impedance on the right and left electrodes
sense is high enough, the film does not affect this voltage, despite its resistive nature.
For the horizontal direction, the same method is used, but by applying supply from left to right.
The range depends on the supply voltage and on the loss in the switches that connect to the top
and bottom electrodes.
In an ideal world (linear, with no loss through switches), the horizontal position is equal to:
The proposed implementation with on-chip power switches is shown in
measurement at the output of the switch compensates for the switches loss.
It is possible to correct for the switch loss by performing the operation:
This requires additional measurements, as shown in
Vertical Position Detection
X
X
M
P
VY
[VY
M
P
Y
/ VDD or VY
- VX
M
Figure
Y
P
M
] / [VX
Volt
VDD
40-2, to detect the position of a contact, a supply is first applied from top to
GND
P
P
X
M
/ VDD.
- VX
Contact
Pen
M
].
X
P
Horizontal Position Detection
Y
Y
M
P
Y
P
Figure
X
P
40-3.
Volt
VDD
GND
Figure
6355B–ATARM–21-Jun-10
40-3. The voltage