Alpha-Numeric Display

Operator Menu Location: Generic Hardware Operators Displays
Operator Bitmap:

Functional Description:
The Alpha-Numeric Display generic hardware operator provides access to an alphanumeric text display resource in the physical hardware. When the generic operator is linked to a specific hardware resource, it will utilize that resource to display a user-defined text message.

The operator has two inputs: a boolean input x1 that determines if the text message is to be displayed, and an analog input x2 used to embed numeric values in the text message.

The text message to be displayed is formed by combining two character strings (operator properties Text Before Number and Text After Number) with the numeric value from analog input x2. In other words, the text message is a concatenation of

[Text Before Number] + [Value from Input x2] + [Text After Number]

If analog input x2 is not used (i.e., if no connection is made to it) the text message that will be displayed is the character string defined in the Text Before Number property (the Text After Number property will not be used).
When the operator is activated (input is HIGH), the user-defined text message will be scrolled from left to right in the physical display. For a hardware resource with n characters, the last n characters of the message will remain on the display after scrolling completes. The duration of the scrolling period (the Entry Time), and the time the message remains on the display (the Hold Time), are properties of the operator.

Multiple generic Alpha-Numeric Display operators can be linked to the same hardware resource. Messages can be assigned a user-defined priority level ranging from 1 to 3. Messages with a higher priority number have precedence over messages with a lower priority number.

While the operator remains active ( ), the text message may repeatedly scroll across the display. The number of times the message is to repeat is a user-configurable property of the operator ranging from 0 to 255. If the repeat property is set to 255, the text message will be displayed indefinitely (as long as the message is active). This display count resets when . Once the operator is reactivated, it will the display the message again and repeat for the user-defined repeat count.

Each text display hardware resource maintains a queue of messages to display. Each queue is sorted based on the priority levels of the messages it contains. The message at the top of the queue is displayed first. After the hold time elapses, the message is removed from the queue and the next message is displayed. If a message is to be repeated, it is re-inserted into the queue, immediately following all messages of equal priority. A message with the number repeat property set to 255 will not be removed from the queue while input is high (it will be displayed indefinitely). Note that a message will not be displayed while messages of higher priority remain in the queue.

User-Defined Properties:
Text Before Number. Text message (or part of text message) to be displayed on the alphanumeric hardware resource when input signal is HIGH. If input is connected, the text message to be displayed is a combination of this property, the numeric value , and the Text After Number property below. Otherwise, if input is not connected, this property defines the full text to be displayed.

Text After Number. The part of text message to be displayed that follows the numeric value of input .

Number of Significant Digits to Display. The number of significant digits to use when displaying the numeric value . This property is ignored if input is not connected.

Justification. The justification of the characters that remain on the screen after the scrolling time expires: Left, Right, or Centered. (This property applies only for text messages whose length does not exceed the number of characters of the physical hardware resource.)

Presentation. The style used to present the message: Steady, Flash, or Fade.

Number Repeat. The number of times to repeat the message while the operator is activated (input is HIGH). If this property is set to 0, the message will be displayed once; if it is set to 1, the message will be displayed twice; if it is set to 2, the message will be displayed three times; and so on. If this property is set to 255, the message will remain on the display as long as input remains HIGH.

Entry Time. The amount of time (in milliseconds) required to scroll the entire message across the display (also called the scrolling period).

Hold Time. The amount of time (in milliseconds) to hold the message on the display after the scrolling period is completed.

Priority. The message priority level: an integer in the range [1,3]. Messages of priority 1 have the lowest priority; messages of priority 3 have the highest priority.

Brightness. A brightness setting for the physical display in the range [0-15], with 15 indicating maximum brightness.

Display Enable Input. This property determines if input pin is visible in the schema diagram. Design Pad issues a warning upon processing the schema when the pin is visible but not connected. The warning message is not issued when the pin is not visible (when this property is not checked).

Display Analog Input. This property determines if input pin is visible in the schema diagram. Design Pad issues a warning upon processing the schema when the pin is visible but not connected. The warning message is not issued when the pin is not visible (when this property is not checked).

Comments:
•Multiple Alpha-Numeric Display operators linked to the same display resource may be active simultaneously. Each active message will be displayed only if all other active messages of higher priority (on the same target line) have been removed from the message queue.
•If a low-priority message is placed in the message queue, and the queue contains a higher priority message with the Number Repeat property set to 255, the low-priority message may never be displayed. (The higher priority message will be displayed until it is deactivated.)
•Modules with alphanumeric display hardware resources may use those resources to display system messages. These system messages may be assigned priority values that are larger than user-defined priorities. As a result, user messages may not be displayed while system messages are displayed.

See Also: Numeric Display, Bargraph Display, LED Display