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Embedded System LCD interactive menu design

Print View , by: iSee ,Total views: 25 ,Word Count: 1912 ,Date: Fri, 21 Aug 2009 Time: 10:02 AM

In recent years, LCD display and the microprocessor to the popularity of the development of high-volume embedded systems human-computer interaction function has been significantly improved. In many occasions, a good graphical user interface (GUI) and convenient operating environment affecting the success or failure is one of the key factors. How to take full advantage of low cost, single-chip microcomputer system has less resources to achieve the perfect man-machine interaction has become a single-chip designers need to address a problem.

At present, many domestic and foreign advanced intelligent instruments, not only in measurement accuracy and sampling rate have higher performance in the friendly human-computer interaction and there are many unique aspects. Author for the German press TOX Intelligent Technology Co., Ltd. developed pressure monitor, the accumulation of a number of embedded systems technology, human-computer interaction experience did not include. In this paper, as examples to introduce the design method.

1 an overview of intelligent pressure monitor

Intelligent pressure monitor for the German press TOX Technology Co., Ltd. developed a special apparatus. The company specializes in the production of sheet metal stamping equipment pieces to connect, in order to ensure the quality of connection required in the process of stamping pressure monitoring; and the measured pressure value and set upper and lower limit comparison of pressure, which determine whether or not qualified. Figure l for the TOX smart pressure monitor system hardware block diagram. It is at the core machine, equipped with pressure and displacement sensors, signal conditioning circuits, LCD liquid crystal display circuit, keys, RS232 and RS485 communication interface, as well as connect with the PLC input / output interface.

Embedded System LCD interactive menu design

TOX Intelligent Control Instrument Pro In addition to pressure ordinary intelligent instrument has a measurement function, data processing and communications functions, is also provided for the user-friendly interactive menu. Through the keys and LCD displays, the flexibility to set and query the following information: measurement procedure and the corresponding pressure on its upper and lower limits; sensor type, specifications and sensitivity; sensor zero offset and offset the maximum extent permitted ; automatic zero calibration function is enabled; communication interface is enabled; communication interface mode and address; the latest data on 10 sets of measurements; user passwords; text types (in Chinese or English); equipment maintenance and operation frequency of the cycle. In addition, with memory protection.

2 control panel and operator interface

Figure 2 shows the pressure monitor TOX smart control panel, the panel has a 160 × 80 dot matrix LCD display and the six buttons. Per line LCD display can show 20 months lO in English or Chinese symbols, a total of 5 lines; six buttons, respectively 0, ENTER, and ESC. Use of these six keys, users can switch "measurement" and "menu" interface, enter the menu interface, users can also easily set up and query the information.

Embedded System LCD interactive menu design

Open the power supply, the device will display the version number, followed by the "Sensor calibration" (to turn off this feature), as shown in Figure 3 and then enter the "measured" interface.

Embedded System LCD interactive menu design

Interface in the measurement, if the received measurement from the PLC command, or the user pressing the "F1" or "F2" key, then began to channel 1 or channel 2 to measure the pressure, followed by processing and displaying measurement results; if the user press "ESC" key, then into the network 4 as shown in the "Main Menu" interface.

After entering the main menu interface, press the "keys to move the cursor; press" ESC "key to return to the previous menu (the" Measurement "menu); press" ENTER "key to enter the selected submenu. For example, when the cursor is located in" measurement procedure " option, if the press "ENTER" button, then enter as shown in Figure 5, "measurement procedure" enter sub-menu.

Embedded System LCD interactive menu design

"Measurement procedure" a total of five sub-menu option, respectively, as well as procedures for channel No. 1 and 2 of the pressure of the upper and lower limits (ie minimum and maximum), the user selected settings are also given. Similarly, the button can move the cursor; press "ESC" key to return to the previous menu (ie main menu); press "ENTER" key to get the cursor location of the lower sub-menu. For example, when the cursor is located in the channel l "minimum" option on, if the press "ENTER" button, then enter as shown in Figure 6 the "minimum" set interface.

Embedded System LCD interactive menu design

Figure 6, the "30.00", said the pressure on channel l is the minimum value 30.00, "_" to the cursor prompt. If users want to modify settings, then click button to move your cursor to the corresponding bit on, and then modify the settings button. For example, when the current cursor position, if by "▲" button, then set the value into a 31.00 by 30.00; if the button, the settings into a 29.00 by 30.00. In this way, only four buttons, you can easily enter settings.

Under the main menu "Sensor Configuration", "data" and "other" option has been nested under a different number of first, second or even multi-level sub-menu for the user's query, modify data and configuration parameters.

It can be seen, although the instrument has six operating buttons and an LCD display, but the smart pressure monitor TOX is still provided to the operator-friendly operating environment, the realization of the human-computer interaction.

3 Human-Computer Interaction Design menu

This design, the main menu and sub menu of up to 20 pages, and there is in both Chinese and English text for the two kinds of user selection, application layer and thus increases the difficulty of programming. Procedures for the use of modular structures, including the following modules:

Switch control interface module: In order to switch the operation requested by user interface, the definition of a register Page_Point image, and its value in between the O ~ Pl changes, P is the number of user interface. If Page_Point = O, the LCD display 0 to display the first form (shown in Figure 3 for the measurement of the interface); If Page_Point = l, is the first LCD monitors to display a form (as shown in Figure 4 for the main menu interface). When the user press "ENTER" or "ESC" key, in accordance with the option to amend the location of the cursor Page_Point value, and then update the display form, the realization of human-computer interaction.

Button scanning module: 6 operating keys on the scan image will be the result of the existence of Key_Status register. The register bit 6, respectively Key_Up, Key_Down, Key_Left, Key_Right, Key_Esc and Key_Enter, followed by the corresponding operation of panels on the six key "ESC" and "ENTER". If the flag for the l, it means that the corresponding button press; the other hand, are loose.

Management control module options: If the current user interface as "interface options" (as shown in Figure 4 and the main menu interface, as shown in Figure 5 Measurement procedures are sub-interface interface option), then press the key, the cursor " > "the location of upward or downward movement of l. To this end, the definition of a register Option_Point image, its value is 0 ~ N-1 (N is the number of options). If the main menu has four options, the N = 4, this time Option_Point for O ~ 3; if the measurement procedure has five sub-menu option, N = 5, at this time Option_Point for 0 ~ 4. Figure 7 for the management and control options of the program module flow chart.

Embedded System LCD interactive menu design

Data entry module: If the current user interface are "buy a few interface" (Figure 6 below set the minimum number of interface on the home belonging to the interface), then press and key, the cursor "_" the location of the left or to the a right move. To this end, the definition of an image Bit_Point register, used to record the data bit can modify the location. Press the key to the current cursor position on the numerical data plus "l" or by "l", for example, as shown in Figure 6, the minimum set of interface, if by "▲" button, then Settings into a 31.00 by 30.00; if by "v" key, then set the value by 30. OO into 29.00. With four keys, you can easily meet the requirements of the importation of any value. Figure 8 for the data entry module of the program flow chart.

The use of these modules, only a small amount of program code on the options to achieve the flexibility to amend the data and interface switching functions.

The design uses assembly language programming, the chip performance j singlechip lower PICl6F877A, although its program memory is only 8KB, but it achieved more than 20 pages of user interface display and switched, as well as dozens of data set and consultation, such as dark and quiet man-machine interactive function, but also the realization of the measurement, control and communications functions.

Embedded System LCD interactive menu design

4 Conclusion

Embedded systems become more perfect human-computer interaction technology. Through the LCD display and a small amount of a few keys, the use of software in embedded system design to achieve the parameters set and data management functions such as human-computer interaction, and enhance the operation of the fun and functionality to enhance the added value of the system.


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