CN115048328A - Trace ball signal conversion method - Google Patents

Abstract

The invention relates to a trackball signal conversion method, which realizes the conversion of PS2 signal or orthogonal signal output by a trackball to RS232 interface signal through a trackball signal conversion device, wherein the switching working mode is judged by high and low levels in the steps so as to generate a serial trackball data format and send the serial trackball data format in a serial port form. The track ball signal conversion method simplifies the track ball signal processing flow, and the ultrasonic system end only needs to receive serial port signals without paying attention to the interface form of the track ball, so that more important tasks are processed by the ultrasonic system. The orthogonal signals comprise X +, X-, Y +, Y-, PS2 signals comprise Data and Clk, and only TXD signals are output after processing.

Description

A trackball signal conversion method

technical field

The present invention relates to medical device processing technology, in particular to a trackball signal conversion method.

Background technique

In the ultrasonic diagnostic system, the trackball can be used to realize man-machine dialogue. For example, when using the measurement function, the object on the screen can be quickly positioned by moving the trackball, which has changed the current situation that the cursor can only be moved in a single direction and a single point by using the keyboard keys. , realizes the arbitrary movement of the cursor in the two-dimensional space, greatly facilitates the user, and improves the efficiency of ultrasonic diagnosis.

Trackball interface types include PS/2, USB, RS232, square wave, etc. The rolling of the trackball will drive the movement of its roller to drive the rotation axis in the X and Y directions. The rolling distance and direction are converted into pulse signals by mechanical or optical methods, such as quadrature square wave signals, and the quadrature signals are directly output, or transmitted to the track. The ball controller and the trackball controller convert the number of pulses into displacement, and output them in serial modes such as RS232, PS2, and USB. The signal output by RS232 does not need a driver, and the serial port applications under the mainstream operating systems such as Windows or Linux on the computer side are fully compatible, and usually do not need to be modified. In addition, the ultrasonic system based on single-chip microcomputer design is relatively easy to receive trackball information through the RS232 interface because the system has undertaken multiple tasks.

However, the trackball using the integrated chip in the prior art has poor anti-interference and insufficient transmission performance stability, and it is difficult to satisfy the transmission signal stability of the ultrasonic diagnostic system.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, a trackball signal conversion method of the present invention, the method realizes the conversion of the PS2 signal or the quadrature signal output by the trackball to the RS232 interface signal through the trackball signal conversion device, including the following steps:

Step S1: the system is initialized, and the flag port is detected;

Step S2: if the flag port is at a high level, enter the PS2 to RS232 working mode, the signal conversion unit simulates the host to initialize the PS2 trackball and set parameters such as sampling rate and resolution, and enter the Stream mode after completion;

Step S3: if the trackball has displacement or button information, it will be sent to the signal conversion unit through the PS2 interface. After the signal conversion unit receives the complete data packet, the information will be converted into the serial trackball data format and sent out in the form of a serial port;

Step S4: if the flag port is at a low level, enter the quadrature signal to RS232 working mode, and the signal conversion unit cyclically reads the quadrature signal port state;

Step S5: if there is a state change, further calculate and generate the displacement information in the X or Y direction and set the position of the movement information flag to 1. The signal conversion unit detects that there is movement information, converts the information into the serial trackball data format, and sends it out in the form of a serial port. .

In an embodiment of the present invention, the trackball signal conversion device is built with STC15W408AS as the center, and an external crystal oscillator circuit is connected, and a power supply is connected to its Vcc and GND terminals, and pins 17 and 18 of PORT1 need to be connected externally. pull.

In an embodiment of the present invention, the input end of the trackball signal conversion device is connected to the quadrature signals X+, X-, Y+, Y- of the trackball, wherein X+ and X- are used to determine the position of the trackball in X Movement in the axis direction, Y+, Y- are used to determine the movement of the trackball in the Y-axis direction.

In an embodiment of the present invention, the input end of the trackball signal conversion device is further provided with a port for accessing the PS2 signal.

In an embodiment of the present invention, the sampling resolution of the trackball is set to 8 count/mm, and the setting is that the host in the trackball signal conversion device first sends 0xE8, after receiving 0xFA, it continues to send 0x03, and then receives 0xFA That is done.

Compared with the prior art, the above technical solution of the present invention has the following advantages: the trackball signal conversion method according to the present invention simplifies the trackball signal processing flow, and the ultrasonic system end only needs to receive the serial port signal, and does not need to pay attention to the interface form of the trackball , freeing up the ultrasound system for more important tasks. The quadrature signal includes X+, X-, Y+, Y-, the PS2 signal includes Data and Clk, and only the TXD signal is output after processing.

Description of drawings

In order to make the content of the present invention easier to understand clearly, the present invention will be described in further detail below according to specific embodiments of the present invention and in conjunction with the accompanying drawings.

Fig. 1 is the flow chart of the trackball quadrature signal conversion method of the present invention;

Fig. 2 is the PS2 signal to RS232 interface signal processing flow chart of the present invention;

Fig. 3 is the block diagram of the trackball signal conversion device of the present invention;

FIG. 4 is a block diagram of the interface conversion circuit according to the present invention.

Detailed ways

This embodiment provides a trackball signal conversion method. The method realizes the conversion of the PS2 signal or quadrature signal output by the trackball to the RS232 interface signal through the trackball signal conversion device, as shown in FIG. 1 and FIG. 2 , It includes the following steps:

Step S1: the system is initialized, and the flag port is detected;

Step S2: if the flag port is at a high level, enter the PS2 to RS232 working mode, the signal conversion unit simulates the host to initialize the PS2 trackball and set parameters such as sampling rate and resolution, and enter the Stream mode after completion;

Step S3: if the trackball has displacement or button information, it will be sent to the signal conversion unit through the PS2 interface. After the signal conversion unit receives the complete data packet, the information will be converted into the serial trackball data format and sent out in the form of a serial port;

Step S4: if the flag port is at a low level, enter the quadrature signal to RS232 working mode, and the signal conversion unit cyclically reads the quadrature signal port state;

Step S5: if there is a state change, further calculate and generate the displacement information in the X or Y direction and set the position of the movement information flag to 1. The signal conversion unit detects that there is movement information, converts the information into the serial trackball data format, and sends it out in the form of a serial port. .

As shown in Figure 3, the input end of the trackball signal conversion device is connected to the quadrature signals X+, X-, Y+, Y- of the trackball, wherein X+ and X- are used to determine the direction of the trackball in the X-axis direction. Move, Y+ and Y- are used to determine the movement of the trackball in the Y-axis direction; if X+ changes before X-, it means the trackball moves in the positive direction of the X-axis, otherwise it means it moves in the opposite direction of the X-axis; Y-change means that the trackball moves in the positive direction of the Y-axis, otherwise it means that it moves in the opposite direction of the Y-axis, and the input end of the trackball signal conversion device also has a port for accessing the PS2 signal.

Further, as shown in Figure 4, the trackball signal conversion device is built with STC15W408AS as the center, and the crystal oscillator circuit is externally connected, and the power supply is connected to its Vcc and GND terminals, and the pins 17 and 18 of PORT1 need to be externally connected. pull up.

Among them, STC15W408AS is STC15 series enhanced 51 single-chip microcomputer, and the existing project is CH9340 developed by Nanjing Qinheng Microelectronics Co., Ltd., which is a USB bus adapter chip, which can realize USB to serial port. But there is no ready-made circuit for PS2 to serial port or quadrature to serial port. Most trackballs with USB ports can output signals compatible with PS2 ports.

And the PS2 interface protocol is a bidirectional synchronous serial protocol, in other words, the PS2 device can send data to the host, and the host can also send data to the device, but the host always has priority on the bus, it can at any time Suppress communication from the device - that is, pull the clock low.

Data sent from the device to the host is read on the falling edge of the clock signal, and data sent from the host to the device is read on the rising edge. Regardless of the direction of communication, the device always generates the clock signal, if the host wants to send data it must first tell the device to start generating the clock signal. The maximum clock frequency is 33kHz, and most devices operate at 10-20kHz.

Unlike the orthogonal or serial trackball, PS2 trackball needs to be initialized when booting up, and its parameters such as sampling rate and resolution can be modified. There is a special command set for initialization and parameter setting, as shown in the table below. Commands are sent by the host, and the trackball is responsible for receiving them. and processing, in the solution of this application, a single-chip computer is used to simulate the host computer to realize the sending and processing of commands, and the command set is shown in the following table;

code Order answer 0xFF reset 0xFA 0xFE Resend 0xXX, 0xXX, 0xXX 0xF6 set as Default 0xFA 0xF5 Data reporting disabled 0xFA 0xF4 data reporting enabled 0xFA 0xF3, 0xXX set sample rate 0xFA, 0xFA 0xF2 read ID 0xFA, 0x00 0xF0 Set to Remote mode 0xFA 0xEE Set to wrap mode 0xFA 0xEC Reset Wrap Mode 0xFA 0xEB read data 0xFA, 0xXX, 0xXX, 0xXX 0xEA Set to Stream mode 0xFA 0xE9 read status 0xFA, 0xXX, 0xXX, 0xXX 0xE8, 0xXX Resolution 0xFA, 0xFA 0xE7 set value conversion 0xFA 0xE6 Cancel numeric conversion 0xFA

After power-on, if the MCU detects that the flag port is at a high level, it enters the PS2-to-serial working mode, completes the MCU initialization first, then delays for a few seconds, and then resets the trackball three times. rate, resolution, and then send 0xF4 to enable the data report, the trackball will respond with 0xFA, so the initialization of the trackball is completed, just wait for the trackball to send data packets, and convert the received data packets into serial trackball data packet format and sent to the ultrasound system control.

The sampling rate generally does not need to be set, and the resolution is set to 8count/mm to meet the needs of B-ultrasound use, that is, the host sends 0xE8 first, and then continues to send 0x03 after receiving 0xFA, and then completes the setting after receiving 0xFA.

Obviously, the above-mentioned embodiments are only examples for clear description, and are not intended to limit the implementation manner. For those of ordinary skill in the art, other different forms of changes or modifications can also be made on the basis of the above description. There is no need and cannot be exhaustive of all implementations here. However, the obvious changes or changes derived from this are still within the protection scope of the present invention.

Claims (5)

1. a trackball signal conversion method, the method realizes the conversion of the PS2 signal or the quadrature signal of the trackball output to the RS232 interface signal by the trackball signal conversion device, is characterized in that, comprises the steps: Step S1: the system is initialized, and the flag port is detected; Step S2: if the flag port is at a high level, enter the PS2 to RS232 working mode, the signal conversion unit simulates the host to initialize the PS2 trackball and set parameters such as sampling rate and resolution, and enter the Stream mode after completion; Step S3: if the trackball has displacement or button information, it will be sent to the signal conversion unit through the PS2 interface. After the signal conversion unit receives the complete data packet, the information will be converted into the serial trackball data format and sent out in the form of a serial port; Step S4: if the flag port is at a low level, enter the quadrature signal to RS232 working mode, and the signal conversion unit cyclically reads the quadrature signal port state; Step S5: If there is a state change, further calculate and generate the displacement information in the X or Y direction and set the position of the movement information flag to 1. The signal conversion unit detects that there is movement information, converts the information into the serial trackball data format, and sends it out in the form of a serial port. . 2. The trackball signal conversion method according to claim 1, wherein the trackball signal conversion device is constructed with STC15W408AS as the center, and a crystal oscillator circuit is externally connected, and a power supply is connected to its Vcc and GND terminals, and Among them, pins 17 and 18 of PORT1 need to be pulled up externally. 3. The trackball signal conversion method according to claim 1, wherein the input end of the trackball signal conversion device is connected to the quadrature signals X+, X-, Y+, Y- of the trackball, wherein X+ , X- are used to determine the movement of the trackball in the X-axis direction, Y+, Y- are used to determine the movement of the trackball in the Y-axis direction. 4 . The trackball signal conversion method according to claim 3 , wherein the input end of the trackball signal conversion device is further provided with a port for accessing PS2 signals. 5 . 5. The trackball signal conversion method according to claim 1, wherein: the sampling resolution of the trackball is set to 8count/mm, and its setting is that the host in the trackball signal conversion device sends 0xE8 first, and waits to receive After 0xFA, continue to send 0x03, and then receive 0xFA to complete.

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