CN102023769A - Scanning device and scanning method for large-scale projected capacitive touch screen - Google Patents

Abstract

The invention discloses a scanning device of a large-size projected capacitive touch screen, which comprises: a group of X-axis slave chips, a group of Y-axis slave chips and a master chip, wherein the master chip is connected to the X-axis slave chips and the Y-axis slave chips, a synchronization pin of the master chip is connected to the synchronization pins of the X-axis slave chips and the Y-axis slave chips, a group of interruption pins of the master chip is respectively connected to the interruption pins of the X-axis slave chips and the Y-axis slave chips, the synchronization pin of the master chip generates a falling edge synchronization signal, the synchronization pins of the X-axis slave chips and the Y-axis slave chips receive the falling edge synchronization signal, scanning the connected sensor to obtain scanning data, generating low signal by the interrupt pin, receiving low signal by the interrupt pin corresponding to the main chip, the data communication is carried out with the slave chip to obtain the scanning data, after the master chip receives the scanning data of all the X-axis slave chips and the Y-axis slave chips, the scanning data is reported to the control computer, and the synchronizing pin of the main chip generates a next falling edge synchronizing signal.

Description

Scanning device and scanning method for large-scale projected capacitive touch screen

technical field

The invention relates to projected capacitive touch screen technology, in particular to a scanning device and a scanning method for a large-scale projected capacitive touch screen.

Background technique

Projected capacitive touch screens are widely used. The basic implementation principle of projected capacitive touch screens is to arrange sensors on the touch screen. These sensors are used to detect vertical and horizontal areas, and chips are used to process the signals sensed by the sensors. touch operation.

The commonly used chip is the CSD module (Capacitive Sensing using a Sigma-Delta Modulator) of the Cypress chip, which can perform capacitive scanning and processing on the sensor of the projected capacitive touch screen. The basic packaging of Cypress chips generally only has 16 pins (pin), 32pin, and 56pin, and the maximum size that can be controlled by a single chip is 7 inches. Therefore, for a projected capacitive touch screen with a large size (>7 inches), there are certain problems in control. If you want to obtain a higher resolution, the number of Sensors used may reach hundreds, and it is impossible to use an existing chip to process it. One solution is to redesign the chip with more pins to accommodate the large size of the touch screen. However, the time and cost required to redesign the chip are huge, and the price of the chip itself will be very expensive, which is obviously not conducive to the application and promotion of large-size touch screens.

Therefore, there is a need for a novel scanning device and scanning method suitable for large-scale projected capacitive touch screens.

Contents of the invention

The purpose of the present invention is to provide a scanning device and a scanning method for a large-scale projected capacitive touch screen. A plurality of existing chips are used to scan a part of the area on the touch screen. The purpose of the chip to scan the large-scale projected capacitive touch screen.

According to one aspect of the present invention, a scanning device for a large-scale projected capacitive touch screen is proposed, including:

A group of X-axis slave chips are respectively connected to the sensors on the X-axis of the projected capacitive touch screen, wherein the number of pins of each X-axis slave chip is less than the number of sensors on the X-axis, and each sensor on the X-axis is connected To one pin of the X-axis slave chip, different X-axis slave pins of the chip are connected to different sensors on the X-axis;

A group of Y-axis slave chips are respectively connected to the sensors on the Y-axis of the projected capacitive touch screen, wherein the number of pins of each Y-axis slave chip is less than the number of sensors on the Y-axis, and each sensor on the Y-axis is connected to To one pin of the Y-axis slave chip, different Y-axis slave pins of the chip are connected to different sensors on the Y-axis;

The master chip is connected to a group of X-axis slave chips and a group of Y-axis slave chips, wherein the synchronization pin of the master chip is connected to the synchronization pins of each X-axis slave chip and each Y-axis slave chip, and the master chip's A group of interrupt pins are respectively connected to the interrupt pins of each X-axis slave chip and each Y-axis slave chip. The synchronization pin of the master chip generates a falling edge synchronization signal. A group of X-axis slave chips and a group of Y-axis slave chips The synchronization pin of the chip receives the falling edge synchronization signal of the synchronization pin of the main chip, and scans the sensor on the X-axis or Y-axis connected to it to obtain scanning data. Each X-axis slave chip or Y-axis slave chip is After completing its own scan, its own interrupt pin generates a low signal, and the interrupt pin corresponding to the master chip receives a low signal, and communicates with the X-axis slave chip or the Y-axis slave chip to obtain the scan data, and the master chip After receiving the scan data of all X-axis slave chips and Y-axis slave chips, report the scan data to the control computer, and the synchronization pin of the master chip generates the next falling edge synchronization signal.

According to one embodiment, there are 56 sensors X1-X56 on the X-axis of the projected capacitive touch screen, and 44 sensors Y1-Y44 on the Y-axis; the set of X-axis slave chips includes a first X-axis slave chip and a second X-axis slave chip. Axis slave chips, where the first X-axis slave chip is connected to the sensors X1-X20 on the X-axis, and the second X-axis slave chip is connected to the sensors X21-X56 on the X-axis; this group of Y-axis slave chips includes the first The Y-axis slave chip and the second Y-axis slave chip, wherein the first Y-axis slave chip is connected to the sensors Y1-Y22 on the Y-axis, and the second Y-axis slave chip is connected to the sensors Y23-Y44 on the Y-axis.

The first X-axis slave chip, Y-axis slave chip and master chip use CY8C21434 chip; the second X-axis slave chip uses CY8C24794 chip.

According to another aspect of the present invention, a scanning method for a large-scale projected capacitive touch screen is proposed, including:

Connect a group of X-axis slave chips to the sensors on the X-axis of the projected capacitive touch screen, wherein the number of pins of each X-axis slave chip is less than the number of sensors on the X-axis, and each sensor on the X-axis is connected To one pin of the X-axis slave chip, different X-axis slave pins of the chip are connected to different sensors on the X-axis;

Connect a group of Y-axis slave chips to the sensors on the Y-axis of the projected capacitive touch screen, wherein the number of pins of each Y-axis slave chip is less than the number of sensors on the Y-axis, and each sensor on the Y-axis is connected To one pin of the Y-axis slave chip, different Y-axis slave pins of the chip are connected to different sensors on the Y-axis;

Connect the master chip to a group of X-axis slave chips and a group of Y-axis slave chips, wherein the synchronization pin of the master chip is connected to the synchronization pin of each X-axis slave chip and each Y-axis slave chip, and the synchronization pin of the master chip A group of interrupt pins are respectively connected to the interrupt pins of each X-axis slave chip and each Y-axis slave chip;

The synchronization pin of the master chip generates a falling edge synchronization signal, and a group of X-axis slave chips and a group of Y-axis slave chips receive the falling edge synchronization signal of the synchronization pin of the master chip, and the connected X-axis or The sensor on the Y axis scans to obtain scanning data;

After each X-axis slave chip or Y-axis slave chip completes its own scan, its own interrupt pin generates a low signal, and the interrupt pin corresponding to the master chip receives a low signal, which is consistent with the X-axis slave chip or Y-axis slave chip. performing data communication to obtain the scan data;

After receiving the scanning data of all X-axis slave chips and Y-axis slave chips, the master chip reports the scan data to the control computer, and the synchronization pin of the master chip generates the next falling edge synchronization signal.

According to one embodiment, there are 56 sensors X1-X56 on the X-axis of the projected capacitive touch screen, and 44 sensors Y1-Y44 on the Y-axis; the set of X-axis slave chips includes a first X-axis slave chip and a second X-axis slave chip. Axis slave chip, connect a group of X-axis slave chips to the sensors on the X-axis of the projected capacitive touch screen, including connecting the first X-axis slave chip to the sensors X1-X20 on the X-axis, connecting the second X-axis slave chip Sensors X21-X56 connected to the X-axis; the group of Y-axis slave chips includes a first Y-axis slave chip and a second Y-axis slave chip, and a group of Y-axis slave chips are respectively connected to the Y-axis of the projected capacitive touch screen The sensors on the board include sensors Y1-Y22 that connect the first Y-axis slave chip to the Y-axis, and sensors Y23-Y44 that connect the second Y-axis slave chip to the Y-axis.

The first X-axis slave chip, Y-axis slave chip and master chip use CY8C21434 chip; the second X-axis slave chip uses CY8C24794 chip.

Adopting the technical solution of the present invention, multiple existing chips are used to control the scanning control of the large-size projected capacitive touch screen, one of which is the master chip, and the rest are slave chips: some chips in the slave chips are used to control X Axis sensor, the other part is used to control the Y-axis sensor. The slave chip is responsible for scanning the sensor, and the master chip is responsible for receiving the scanning results reported by the slave chip and making the final data processing. The slave chip communicates with the master chip through the standard I2C interface and the interrupt pin, and the master chip performs synchronous control on the slave chip through the synchronization pin, which ensures that all the slave chips will not be delayed due to timing confusion. Or dislocation phenomenon, to ensure the accuracy and timeliness of the data.

Description of drawings

Fig. 1 discloses the structural diagram of the scanning device of the large-scale projected capacitive touch screen of the present invention;

FIG. 2 discloses a flow chart of the scanning method of the large-size projected capacitive touch screen of the present invention.

Detailed ways

The scanning device of the large-scale projected capacitive touch screen of the present invention includes a set of X-axis slave chips, a set of Y-axis slave chips and a master chip.

A group of X-axis slave chips are respectively connected to the sensors on the X-axis of the projected capacitive touch screen, wherein the number of pins of each X-axis slave chip is less than the number of sensors on the X-axis, and each sensor on the X-axis is connected to a The X axis is from one pin of the chip, and different X axes are connected to different sensors on the X axis from the pins of the chip.

A group of Y-axis slave chips are respectively connected to the sensors on the Y-axis of the projected capacitive touch screen, wherein the number of pins of each Y-axis slave chip is less than the number of sensors on the Y-axis, and each sensor on the Y-axis is connected to a The Y axis is from one pin of the chip, and different Y axes are connected to different sensors on the Y axis from the pins of the chip.

The master chip is connected to a group of X-axis slave chips and a group of Y-axis slave chips, wherein the synchronization pin of the master chip is connected to the synchronization pins of each X-axis slave chip and each Y-axis slave chip, and the master chip A group of interrupt pins are respectively connected to the interrupt pins of each X-axis slave chip and each Y-axis slave chip, the synchronization pin of the master chip generates a falling edge synchronization signal, a group of X-axis slave chips and a group of Y-axis slave chips The synchronization pin of the slave chip receives the falling edge synchronization signal of the synchronization pin of the master chip, and scans the sensor on the X-axis or Y-axis connected to it to obtain scanning data. Each X-axis slave chip or Y-axis slave chip After completing its own scan, its own interrupt pin generates a low signal, and the interrupt pin corresponding to the main chip receives a low signal, and communicates with the X-axis slave chip or the Y-axis slave chip to obtain scanning data, and the main chip receives a low signal. After receiving the scan data of all X-axis slave chips and Y-axis slave chips, report the scan data to the control computer, and the synchronization pin of the master chip generates the next falling edge synchronization signal.

FIG. 1 discloses a structural diagram of an implementation of a scanning device for a large-scale projected capacitive touch screen of the present invention. In this embodiment, the large-sized projected capacitive touch screen is a 17-inch projected capacitive touch screen 40, the projected capacitive touch screen has 56 sensors X1-X56 on the X axis, and 44 sensors Y1-Y44 on the Y axis. In this embodiment, a set of X-axis slave chips includes a first X-axis slave chip 10 and a second X-axis slave chip 11, the first X-axis slave chip 10 is connected to the sensors X1-X20 on the X-axis, and the second X-axis slave chip 10 is connected to the sensors X1-X20 on the X-axis. The axis is connected from chip 11 to sensors X21-X56 on the X axis. A group of Y-axis slave chips includes a first Y-axis slave chip 20 and a second Y-axis slave chip 21, the first Y-axis slave chip 20 is connected to the sensors Y1-Y22 on the Y-axis, and the second Y-axis slave chip 21 is connected to Sensors Y23-Y44 on the Y axis. The master chip 30 is connected to the first X-axis slave chip 10 , the second X-axis slave chip 11 , the first Y-axis slave chip 20 , and the second Y-axis slave chip 21 . The synchronous pin of main chip 30 is connected to the synchronous pin of the first X-axis slave chip 10, the second X-axis slave chip 11, the first Y-axis slave chip 20, and the second Y-axis slave chip 21. The group interrupt pins are respectively connected to the interrupt pins of the first X-axis slave chip 10 , the second X-axis slave chip 11 , the first Y-axis slave chip 20 , and the second Y-axis slave chip 21 . The first X-axis slave chip 10, the first Y-axis slave chip 20, the second Y-axis slave chip 21 and the master chip 30 use the CY8C21434 chip, while the second X-axis slave chip 11 uses the CY8C24794 chip.

The workflow of the scanning device of the large-size projected capacitive touch screen shown in Figure 1 is roughly as follows:

The main chip performs synchronous control on the slave chip through the synchronization pin: the synchronization pin of the main chip generates a falling edge, when the slave chip (including the first X-axis slave chip, the second X-axis slave chip, the first Y-axis slave chip, the second Two Y-axis slave chips) detect that the synchronization pin of the master chip has a falling edge, and the slave chips start scanning at the same time. This ensures that multiple slave chips will not cause hysteresis or misalignment of the data obtained due to timing confusion, ensuring the accuracy and timeliness of the data.

After each slave chip scans all the sensors responsible for it for a round, it processes the obtained scanning results. After the processing is completed, it pulls its own interrupt pin low to notify the master chip that "it is time to read the results".

The interrupt pin corresponding to the master chip receives the interrupt falling edge from a certain slave chip, and will read the data reported by it through I2C. After receiving all the current round of data reported by the slave chip, the master chip makes the final data processing. The data communication between the master chip and the slave chip is realized through the I2C interface.

The main chip sends the final result to the control computer through the UART interface, and the final result is the result after the main chip processes the reported data of each slave chip.

After the master chip completes a data report to the control computer, it will generate a falling edge on the synchronization pin again to notify all slave chips to start the next round of scanning.

In one embodiment, the data format sent from each chip to the master chip is as follows:

Byte0 Byte1 Byte2 Byte3 Byte4 =0 0xFF 0xFF 0xFF 0xFF = 1 Peak1 0xFF Coordinate high byte Coordinate low byte = 2 Peak1 Peak2 0xFF 0xFF

Byte0 indicates the number of touch points (0, 1, 2)

Peak1 means that if there is 1 touch point, this value represents the number of the touched sensor.

Peak2 means that if there are 2 touch points, this value represents the number of another touched sensor.

In one embodiment, the number of grids of data sent by the main chip to the control computer is as follows:

Byte0 indicates the number of touch points (0, 1, 2)

PeakX1, PeakX2, PeakY1, and PeakY2 represent the numbers of the touched sensors on the X-axis and Y-axis.

After each slave chip scans all the sensors it is responsible for, it is responsible for judging whether there is a touch action in the area according to the scanning results and the characteristics of the sensor. If there is a touch, it must be judged whether it is a single-finger touch or a two-finger touch. Then calculate the specific position of the touch point in this area, and report to the main chip.

The main chip makes a summary based on the data reported by each slave chip, and finally confirms that there are a total of several touch points, and calculates the exact coordinates of the touch points on the entire touch screen, and transmits the data to the control computer through UART. If a single finger continues to move on the touch screen, the main chip also makes smooth corrections to the coherent coordinates, so that the coordinate data obtained by the control computer can be connected to a smooth curve.

In the case that 100 sensors need to be scanned at the same time, such a data format can minimize the data read by I2C communication and the data output from UART to the control computer, which greatly saves the time spent in each link and ensures up to 60fps reporting rate. If the reporting rate is lower than 40fps, the handwriting effect will be very poor, and problems such as broken lines, broken lines, jumping lines, and uneven lines will easily occur. It cannot be used as a touch device on an instrument that requires high-resolution handwriting functions such as computer monitors. .

Referring to Fig. 2, the present invention also discloses a scanning method of a large-scale projected capacitive touch screen, including the following steps:

20. Connect a group of X-axis slave chips to the sensors on the X-axis of the projected capacitive touch screen, wherein the number of pins of each X-axis slave chip is less than the number of sensors on the X-axis, and each pin on the X-axis The sensor is connected to one pin of the X-axis slave chip, and different sensors on the X-axis are connected to different X-axis slave chip pins;

21. Connect a group of Y-axis slave chips to the sensors on the Y-axis of the projected capacitive touch screen, wherein the number of pins of each Y-axis slave chip is less than the number of sensors on the Y-axis, and each The sensor is connected to one pin of a Y-axis slave chip, and different Y-axis slave chip pins are connected to different sensors on the Y-axis;

22. Connect the master chip to a group of X-axis slave chips and a group of Y-axis slave chips, wherein the synchronization pin of the master chip is connected to the synchronization pin of each X-axis slave chip and each Y-axis slave chip, the master A group of interrupt pins of the chip are respectively connected to the interrupt pins of each X-axis slave chip and each Y-axis slave chip;

23. The synchronization pin of the main chip generates a falling edge synchronization signal, and a group of X-axis slave chips and a group of Y-axis slave chip synchronization pins receive the falling edge synchronization signal of the synchronization pin of the main chip. Scan the sensor on the axis or Y axis to obtain scanning data;

24. After each X-axis slave chip or Y-axis slave chip completes its own scan, its own interrupt pin generates a low signal, and the interrupt pin corresponding to the main chip receives a low signal, which is consistent with the X-axis slave chip or Y-axis performing data communication from the chip to obtain the scan data;

25. After the main chip receives the scanning data of all X-axis slave chips and Y-axis slave chips, it reports the scanning data to the control computer, and the synchronization pin of the main chip generates the next falling edge synchronization signal.

Referring to the structural diagram of the embodiment shown in FIG. 1, in an implementation of the present invention, there are 56 sensors X1-X56 on the X-axis of the projected capacitive touch screen, and 44 sensors Y1-Y44 on the Y-axis;

A group of X-axis slave chips includes a first X-axis slave chip and a second X-axis slave chip, and connecting a group of X-axis slave chips to the sensors on the X-axis of the projected capacitive touch screen includes connecting the first X-axis slave chip To the sensors X1-X20 on the X-axis, connect the second X-axis slave chip to the sensors X21-X56 on the X-axis; a set of Y-axis slave chips includes the first Y-axis slave chip and the second Y-axis slave chip, connect the A group of Y-axis slave chips are respectively connected to the Y-axis sensors of the projected capacitive touch screen, including sensors Y1-Y22 connected to the first Y-axis slave chip to the Y-axis, and the second Y-axis slave chip is connected to the Y-axis The sensors Y23-Y44.

In one embodiment, the first X-axis slave chip, the Y-axis slave chip and the master chip use a CY8C21434 chip; the second X-axis slave chip uses a CY8C24794 chip.

The detailed description of the method disclosed in FIG. 2 is consistent with the device disclosed in FIG. 1 , and will not be repeated here.

Adopting the technical solution of the present invention, multiple existing chips are used to control the scanning control of the large-size projected capacitive touch screen, one of which is the master chip, and the rest are slave chips: some chips in the slave chips are used to control X Axis sensor, the other part is used to control the Y-axis sensor. The slave chip is responsible for scanning the sensor, and the master chip is responsible for receiving the scanning results reported by the slave chip and making the final data processing. The slave chip communicates with the master chip through the standard I2C interface and the interrupt pin, and the master chip performs synchronous control on the slave chip through the synchronization pin, which ensures that all the slave chips will not be delayed due to timing confusion. Or dislocation phenomenon, to ensure the accuracy and timeliness of the data.

Claims (6)

1. A scanning device for a large-scale projected capacitive touch screen, characterized in that it comprises: A group of X-axis slave chips are respectively connected to the sensors on the X-axis of the projected capacitive touch screen, wherein the number of pins of each X-axis slave chip is less than the number of sensors on the X-axis, and each sensor on the X-axis is connected To one pin of the X-axis slave chip, different X-axis slave pins of the chip are connected to different sensors on the X-axis; A group of Y-axis slave chips are respectively connected to the sensors on the Y-axis of the projected capacitive touch screen, wherein the number of pins of each Y-axis slave chip is less than the number of sensors on the Y-axis, and each sensor on the Y-axis is connected to To one pin of the Y-axis slave chip, different Y-axis slave pins of the chip are connected to different sensors on the Y-axis; The master chip is connected to the set of X-axis slave chips and a group of Y-axis slave chips, wherein the synchronization pin of the master chip is connected to the synchronization pins of each X-axis slave chip and each Y-axis slave chip, A group of interrupt pins of the master chip are respectively connected to the interrupt pins of each X-axis slave chip and each Y-axis slave chip, and the synchronization pin of the master chip generates a falling edge synchronization signal, and the group of X-axis The slave chip and a group of Y-axis slave chips receive the falling edge synchronization signal of the synchronization pin of the master chip, scan the sensor on the X-axis or Y-axis connected to it, and obtain scanning data, each X-axis After the slave chip or the Y-axis slave chip completes its own scan, its own interrupt pin generates a low signal, and the interrupt pin corresponding to the main chip receives a low signal, and communicates with the X-axis slave chip or the Y-axis slave chip for data communication. After obtaining the scan data, the master chip reports the scan data to the control computer after receiving the scan data of all X-axis slave chips and Y-axis slave chips, and the synchronization pin of the master chip generates the next falling edge synchronization signal. 2. the scanning device of large-scale projected capacitive touch screen as claimed in claim 1, is characterized in that, There are 56 sensors X1-X56 on the X axis of the projected capacitive touch screen, and 44 sensors Y1-Y44 on the Y axis; The group of X-axis slave chips includes a first X-axis slave chip and a second X-axis slave chip, wherein the first X-axis slave chip is connected to the sensors X1-X20 on the X-axis, and the second X-axis slave chip is connected to Sensors X21-X56 on the X axis; The group of Y-axis slave chips includes a first Y-axis slave chip and a second Y-axis slave chip, wherein the first Y-axis slave chip is connected to the sensors Y1-Y22 on the Y-axis, and the second Y-axis slave chip is connected to Sensors Y23-Y44 on the Y axis. 3. The scanning device of large-scale projected capacitive touch screen as claimed in claim 2, is characterized in that, The first X-axis slave chip, Y-axis slave chip and master chip use CY8C21434 chip; The second X-axis slave chip uses CY8C24794 chip. 4. A scanning method for a large-scale projected capacitive touch screen, characterized in that it comprises: Connect a group of X-axis slave chips to the sensors on the X-axis of the projected capacitive touch screen, wherein the number of pins of each X-axis slave chip is less than the number of sensors on the X-axis, and each sensor on the X-axis is connected To one pin of the X-axis slave chip, different X-axis slave pins of the chip are connected to different sensors on the X-axis; Connect a group of Y-axis slave chips to the sensors on the Y-axis of the projected capacitive touch screen, wherein the number of pins of each Y-axis slave chip is less than the number of sensors on the Y-axis, and each sensor on the Y-axis is connected To one pin of the Y-axis slave chip, different Y-axis slave pins of the chip are connected to different sensors on the Y-axis; Connecting the master chip to the set of X-axis slave chips and a group of Y-axis slave chips, wherein the synchronization pin of the master chip is connected to the synchronization pins of each X-axis slave chip and each Y-axis slave chip, A group of interrupt pins of the main chip are respectively connected to the interrupt pins of each X-axis slave chip and each Y-axis slave chip; The synchronization pin of the master chip generates a falling edge synchronization signal, and the group of X-axis slave chips and a group of Y-axis slave chips receive the falling edge synchronization signal of the synchronization pin of the master chip, and the connected The sensor on the X-axis or Y-axis scans to obtain scanning data; After each X-axis slave chip or Y-axis slave chip completes its own scan, its own interrupt pin generates a low signal, and the interrupt pin corresponding to the master chip receives a low signal, which is consistent with the X-axis slave chip or Y-axis slave chip. performing data communication to obtain the scan data; After the master chip receives the scan data of all the X-axis slave chips and the Y-axis slave chips, it reports the scan data to the control computer, and the synchronization pin of the master chip generates the next falling edge synchronization signal. 5. the scanning method of large-scale projected capacitive touch screen as claimed in claim 4, is characterized in that, There are 56 sensors X1-X56 on the X axis of the projected capacitive touch screen, and 44 sensors Y1-Y44 on the Y axis; The group of X-axis slave chips includes a first X-axis slave chip and a second X-axis slave chip, and connecting a group of X-axis slave chips to the sensors on the X-axis of the projected capacitive touch screen includes connecting the first X-axis slave chip to the X-axis sensor of the projected capacitive touch screen. The chip is connected to the sensors X1-X20 on the X-axis, and the second X-axis is connected from the chip to the sensors X21-X56 on the X-axis; Described one group of Y-axis slave chips comprises the first Y-axis slave chip and the second Y-axis slave chip, and connecting one group of Y-axis slave chips to the sensors on the Y-axis of the projected capacitive touch screen includes connecting the first Y-axis slave chip The chip is connected to sensors Y1-Y22 on the Y-axis, and the second Y-axis slave chip is connected to sensors Y23-Y44 on the Y-axis. 6. the scanning method of large-scale projected capacitive touch screen as claimed in claim 5, is characterized in that, The first X-axis slave chip, Y-axis slave chip and master chip use CY8C21434 chip; The second X-axis slave chip uses CY8C24794 chip.

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