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3 Common User Interface

3.1 Introduction

Several of the tools (LE Panel, LE ASMB, ED PLD, and TERM) were written to run in the DESQview environment. They will not run unless DESQview is installed and running. The DESQview environment offers three major features utilized by these tools: the ability to switch between applications, a standard way of dealing with windows and fields, and the ability to multitask. These tools also share a common philosophy towards the user interface. Wherever possible, a common interface was used to accomplish similar tasks. This is most notable in the menus, file I/O, dialog boxes, and the DESQview interface.

3.2 DESQview Interface

After the tools have been installed, they can be started from the DESQview menu. This is assuming the advanced installation procedure was used. The DESQview menu is usually displayed in the upper right hand corner of the screen but at times the menu will be hidden. If so, simply hit the DESQview key () to redisplay the menu. The DESQview menu is illustrated in Figure 1.

To open a tool, first select the Open Window item from the DESQview menu. This can be done by either moving the cursor over the item with the cursor keys or mouse and hitting the space bar, Enter key or left mouse button, or by simply typing the letter O. This will open up the Open Window menu. From here, a tool can be selected either by moving the cursor over the entry and hitting the space bar or the enter key or by typing the letters associated with the tool. If the entry is not visible on this menu, the Page Down key can be used to list more entries. Once selected, a window will be opened for that tool.

DESQview also provides an interface for managing the windows. These functions include: moving, resizing, scrolling, closing and switching windows. See the DESQview manual for details about these and other functions provided by the DESQview interface.

In various situations there will be a selection of fields presented from which the user must choose, or a field in which the user must enter text. In general, the cursor keys or the mouse can be used to move between the fields and the space bar, Enter key or left mouse button can be used to select the field the cursor is over. The exception is in the case of a window that has a field in which text is to be entered. In this case the key moves the cursor to the next field and thed Shift- key moves to the previous field. The space bar can be used to select the field that the cursor is over. Text is entered into fields by moving the cursor over the field and entering the text. The text can be edited using the left and right cursor keys, the end, home, insert, delete, and backspace keys. As a general rule the key will cause the current activity to be aborted.

3.3 Menus

Each of the tools that conform to the Common User Interface (LE Panel, LE ASMB, ED PLD, and TERM) have a common menu interface. Across the top of the window of each of these tools, is a menu bar consisting of six fields. The first is the name of the application and has a special function described later. The next five are menu fields, the first labeled File, the fourth and the fifth labeled Tools and HELP respectively. The second and third menu fields are labeled differently for each tool. Each of the menu fields is associated with a function key shown parenthetically in each field. The date of the last modification of the tool is shown on the far right of the menu bar.

The menus can be activated either by selecting them as described above or by pressing the associated function key. For example, the Tools menu can be activated by pressing the F4 key. When a menu is activated, a small pull-down menu containing a list of possible selections is displayed below the menu title. The Display menu for the LE Panel tool is shown in Figure 2. Displayed to the right of each selection is an associated key stroke. The key strokes preceded by an `A-' refer to the key combined with the key. Those preceded by a `C-' refer to the key combined with the key. This key stroke is used as a quick way to select an item without first selecting a menu. They are not available when a menu is active. The actions that are performed when each menu item is selected are described in detail in the respective chapter for that tool. The key can be used to exit the menu without selecting an item. To activate another menu while one is currently active, the mouse, the left and right cursor keys, or the function keys for the menus can be used.

The first field of the menu bar which contains the name of the tool, is the icon field. When selected, the window for the tool is reduced to the size of this field and positioned at the far right of the screen. When selected again, the window is expanded to full size and repositioned. This is useful when you want to hide the window for a time without exiting the tool.

3.4 Dialog Boxes

At various times the user will be prompted for input with a dialog box. This is simply a small window that appears on top of the current window and has a selection of fields to choose from and/or a field in which to enter text. The fields can be selected as described above. Figure 3 shows a field definition dialog box from the LE Panel tool.

3.5 File I/O

When a requested operation requires a file name, the user is prompted with the browser dialog box, as illustrated in Figure 4. From here the user can type in a file name, select a file from a list, change directories, or change drives. The browser dialog box consists of five major sections: the file name field, the scroll control fields, the directory listing, the file listing, and the drive select fields. The file name field is located at the top right of the browser menu and is used to enter a file name or file name pattern (contains one or more of '*' or '?'). When the enter key is entered into this field, the file name is accepted. If it is not a pattern, the browser menu is closed, and the appropriate action is taken on the named file. If it is a file name pattern, the file listing is updated with only those files which match the pattern.

The directory and file listing sections are located in the middle of the browser dialog box - the directory listing on the left and the file listing on the right. These contain a listing of up to ten of the subdirectories and files of the current directory. If there are more than ten subdirectories or files, the scroll control fields for each listing can be used. These are located just above each listing. Each has two controls, one for scrolling up (on the left) and one for scrolling down (on the right). When one of these fields is selected, the corresponding listing will scroll up or down.

Selecting one of the items in the directory listing section will change the current directory. A new directory and file listing will be displayed. The path of the current directory will be displayed just below the file name field. To move up one level in the directory tree, the sub-directory name ".." can be selected.

Selecting one of the items in the file listing section will accept that file name. The browser dialog box is closed and the appropriate action is taken on the selected file name.

The drive select fields are located at the bottom of the browser dialog box, labeled with the drive letters with the current drive highlighted. Selecting one of the drives will change the current drive, update the directory and file listings, and update the path of the current directory.

The ESC key can be used to abort out of the browser with a null file name being accepted and the appropriate action being performed for a null file (usually nothing). However, a change of the current directory or drive will take effect no matter how the browser is exited. Subsequent file I/O will be relative to the new current directory and drive.

There are several shortcuts available for the browser that allow the user to avoid having to move the cursor around a lot with the cursor keys or the mouse. They are listed below:

Home	Move the cursor to the File Name field
Page_Up	Scroll File Listing up
Page_Down	Scroll File Listing down
Page_Up	Scroll Directory Listing up
Page_Down	Scroll Directory Listing down
n	Selects the nth item in the File Listing, where n is one of the numeric keys (1 representing the first item and 0 representing the tenth item).
c	Changes to the directory indicated by the letter c, where c is one of the keys on the top row of the keyboard starting with q (representing the first item) and ending with p (representing the tenth item).
c	Changes to the drive indicated by the letter c, where c is one of the keys on the bottom row of the keyboard starting with z (representing drive A) and ending with m (representing drive G).

3.6 Tools Menu

Each of the tools that conform to the Common User Interface (LE Panel, LE ASMB, ED PLD, and TERM) have an identical tools menu. This menu consists of five selections used to start up one of the tools or a DOS window. The key strokes associated with each selection are identical within each tool. They are:

F10	- LE Panel
F10	- LE ASMB
F11	- ED PLD
F11	- TERM
F11	- DOS

3.7 Help System

Each of the tools that conform to the Common User Interface (LE Panel, LE ASMB, ED PLD, and TERM) use a common help system. Figure 5 shows the help dialog box for the LE Panel tool. The help dialog box consists of three fields across the top and a display area below. The display area contains a portion of the help information. The first two fields are used to scroll through the help information and the third is used to close the help dialog box.

3.8 Communication with the LE Board

Most of the tools need to communicate with the LE Board at various times. In order to do this, the LE Board must be installed and turned on. Before any communication is attempted, the tool will first determine if the LE Board is active, if so the communication will take place, if not the communication is aborted and a dialog box as shown in Figure 6, is displayed indicating that the LE Board is not responding. This dialog box can be closed by pressing the key or the left mouse button. This will prevent most communication attempts when the board is not installed. However, if the board is turned off or disconnected while the tool is running, the tool can get confused and may attempt to communicate with a non-functioning board. In this case it is possible for the tool to become hung.

Another problem that can arise while communcating with the LE Board is due to multitasking. Since more than one tool can be running at the same time, it is possible for more than one tool to be commmunicating with the board. The system allows only one tool to communicate with the board at any one time. The problem can occur when the communications of several tools are interweaved, such as:

(a) tool A reads the state of the board, while
(b) tool B changes the state of the board, just as
(c> tool A acts based on the state it read (which is now invalid)

The system does little to prevent this situation, so it is best to avoid it. It does attempt to prevent it if tool A and tool B in the example above are the same tool. In the case of the LE ASMB and ED PLD tools, if subsequent instances of the tool are opened, the subseqent ones are not allowed to communicate with the board. This is indicated by a bell when the window is opened. In the case of the LE Panel tool, subseqent instances are not allowed. If a second instance is opened it is immediately closed and the first instance is raised to be the top window.

Logic Engine User Manual Index

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