TMP91xy25FG Toshiba, TMP91xy25FG Datasheet - Page 160

• Manufacturer Part Number: TMP91xy25FG
• Manufacturer: Toshiba

Specifications of TMP91xy25FG

• Package: LQFP100
• Rom Types(m=mask,p=otp, F=flash,e=eeprom): Romless
• Rom Combinations: Romless
• Ram Combinations: Ramless
• Architecture: 16-bit CISC
• Usb/spi Channels: -
• Uart/sio Channels: 2
• I2c/sio Bus Channels: -
• (s)dram Controller: -
• Adc 10-bit Channel: 4
• Da Converter: -
• Timer 8-bit Channel: 4
• Timer 16-bit Channel: -
• Pwm 8-bit Channels: -
• Pwm 16-bit Channels: -
• Cs/wait Controller: 4
• Dual Clock: Y
• Number Of I/o Ports: 49
• Power Supply Voltage(v): 3.0 to 3.6

3.10.4
Touch screen resistor:
SMY (SMX)
ON resistor:
SPY (SPX)
ON resistor: Rpy (Rpx)
Rty (Rtx)
A value depends on
a touch screen.
Rmy (Rmx)
typ.20 Ω
typ.20 Ω
X/Y Position Measuring Procedure
<X position measurement>
<Y position measurement>
In the INT2 routine, execute an X/Y position measuring procedure like below.
P83/MY/AN3 pin. The X position can be measured by converting this voltage to digital
code with AD converter.
P82/MX/AN2 pin. The Y position can be measured by converting this voltage to digital
code with AD converter.
touch screen shown in Figure 3.10.5.
be to 3.3 V or 0.0 V.
be adopted as a correct code.
At first, ON both SPX and SMX-switches and OFF SPY, SMY-switches.
By this setting, analog-voltage which shows the X position will be inputted to
Next, ON both SPY and SMY-switches and OFF SPX, SMX-switches.
By this setting, analog voltage which shows the Y position will be inputted to
The above analog voltage which is inputted to AN3 or AN2 pin can be calculated.
It is a ratio between resistance value in TMP91C025FG and resistance value in
Therefore, if the pen touches a corner area on touch screen, analog-voltage will not
As a notice, since each resistor has an uneven, consider about it.
And it is recommended that an average code among a few times AD conversion will
AVCC = 3.3 V
R2
R1
Figure 3.10.5 Calculation Analog Voltage
Touch point
AN2 (AN3) pin
91C025-158
[Formula to calculate analog voltage (E1) to AN2 or AN3 pin]
Note 1: An X position can be calculated in the same way
Note 2: Rty = R1 + R2.
(Example) The case of AVCC = 3.3 V, Rpy = Rmy = 20 Ω,
E1 = ((R2 + Rmy)/(Rpy + Rty + Rmy)) × AVCC [V]
though above formula is for Y position.
R1 = 400 Ω and R2 = 100 Ω
E1 = ((100 + 20)/(20 + 400 + 100 + 20) × 3.3
= 0.733 V
TMP91C025
2007-02-28