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參數(shù)資料
| 型號： | ADS7846 |
| 元件分類： | 通用總線功能 |
| 英文描述： | CMOS 8-Stage Presettable 8-Bit Binary Synchronous Down Counter 16-TSSOP -55 to 125 |
| 中文描述： | 觸摸屏控制器 |
| 文件頁數(shù)： | 12/23頁 |
| 文件大小： | 520K |
| 代理商： | ADS7846 |
ADS7846
SBAS125H
12
www.ti.com
The first eight clock cycles are used to provide the control
byte via the DIN pin. When the converter has enough
information about the following conversion to set the input
multiplexer and reference inputs appropriately, the converter
enters the acquisition (sample) mode and, if needed,
the touch panel drivers are turned on. After three more
clock cycles, the control byte is complete and the converter
enters the conversion mode. At this point, the input
FIGURE 9. Conversion Timing, 24 Clocks-per-Conversion, 8-bit Bus Interface. No DCLK delay required with dedicated
serial port.
PRESSURE MEASUREMENT
Measuring touch pressure can also be done with the ADS7846.
To determine pen or finger touch, the pressure of the touch
needs to be determined. Generally, it is not necessary to have
very high performance for this test; therefore, the 8-bit resolu-
tion mode is recommended (however, calculations will be
shown here are in 12-bit resolution mode). There are several
different ways of performing this measurement. The ADS7846
supports two methods. The first method requires knowing the
X-plate resistance, measurement of the X-Position, and two
additional cross-panel measurements (Z
1
and Z
2
) of the touch
screen, as shown in Figure 8. Using Equation 2 calculates the
touch resistance:
R
R
plate
X
Position Z
4096
Z
TOUCH
X
=
–
–
–
1
2
1
(2)
The second method requires knowing both the X-plate and
Y-plate resistance, measurement of X-Position and Y-Posi-
tion, and Z
1
. Using Equation 3 also calculates the touch
resistance:
R
R
plate
X
4096
Position
4096
Z
–
1
–
R
plate
Y Position
4096
TOUCH
X
1
Y
=
1
–
(3)
DIGITAL INTERFACE
Figure 9 shows the typical operation of the ADS7846 digital
interface. This diagram assumes that the source of the
digital signals is a microcontroller or digital signal processor
with a basic serial interface. Each communication between
the processor and the converter, such as SPI/SSI or
Microwire
synchronous serial interface, consists of eight
clock cycles. One complete conversion can be accom-
plished with three serial communications for a total of 24
clock cycles on the DCLK input.
FIGURE 8. Pressure Measurement Block Diagrams.
t
ACQ
Acquire
Idle
Conversion
Idle
1
DCLK
CS
8
1
11
DOUT
BUSY
DRIVERS 1 AND 2
(1)
(SER/DFR High)
DRIVERS 1 AND 2
(1, 2)
(SER/DFR Low)
(MSB)
(START)
(LSB)
A2
S
On
On
Off
Off
Off
Off
DIN
A1
A0
MODE
DFR
PD1 PD0
10
9
8
7
6
5
4
3
2
1
0
Zero Filled...
8
1
8
NOTES: (1) For Y-Position, Driver 1 is on, X+ is selected, and Driver 2 is off. For X-Position, Driver 1 is off, Y+ is selected, and
Driver 2 is on. Y
–
will turn on when power-down mode is entered and PD0 = 0
. (2) Drivers will remain on if PD0 = 1 (no power
down) until selected input channel, reference mode, or power-down mode is changed, or CS is HIGH.
X-Position
Measure X-Position
Measure Z
1
-Position
Touch
X+
Y+
X
–
Y
–
Z
1
-Position
Touch
X+
Y+
Y
–
X
–
Measure Z
2
-Position
Z
2
-Position
Touch
X+
Y+
Y
–
X
–
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ADS7846E | CMOS 8-Stage Presettable 8-Bit Binary Synchronous Down Counter 16-TSSOP -55 to 125 |
| ADS7852YB | 12-Bit, 8-Channel, Parallel Output ANALOG-TO-DIGITAL CONVERTER |
| ADS7852 | 12-Bit, 8-Channel, Parallel Output ANALOG-TO-DIGITAL CONVERTER |
| ADS7852Y | CMOS 8-Stage Presettable 8-Bit Binary Synchronous Down Counter 16-CDIP -55 to 125 |
| ADS7861 | CMOS 8-Stage Presettable 8-Bit Binary Synchronous Down Counter 16-CDIP -55 to 125 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ADS7846AE | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| ADS7846AN | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| ADS7846E | 功能描述:觸摸屏轉(zhuǎn)換器和控制器 4-wire Touch Screen Controller RoHS:否 制造商:Microchip Technology 類型:Resistive Touch Controllers 輸入類型:3 Key 數(shù)據(jù)速率:140 SPS 分辨率:10 bit 接口類型:4-Wire, 5-Wire, 8-Wire, I2C, SPI 電源電壓:2.5 V to 5.25 V 電源電流:17 mA 工作溫度:- 40 C to + 85 C 封裝 / 箱體:SSOP-20 |
| ADS7846E | 制造商:Texas Instruments 功能描述:IC 4-WIRE TOUCH SCRN CONT 16QSOP 制造商:Texas Instruments 功能描述:IC, 4-WIRE TOUCH SCRN CONT 16QSOP |
| ADS7846E | 制造商:Texas Instruments 功能描述:IC's |
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