Step 2: Adding Setting A-variables
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This step corresponds to test_agg_lib_2.
In this step we are going to add necessary setting A-variables. These will be used to store the few configuration and status parameters our application requires.
A-variables we are going to have are:
•The BR setting to store the baudrate of the serial port. This will allow us to select a standard baudrate from a list of baudrates (like 9600, 19200, etc.)
•The EG setting to enable/disable access control event generation.
•The UT setting to store the unlock time for the door. This is the number of half-second intervals that the door lock will stay unlocked for (once it is unlocked).
•The DS setting for reading the current door state (closed or opened).
Looking now at the test_agg_lib_2 project, notice that...
2. A way to initialize settings is provided. After each boot, the device will start blinking its red and green status LEDs. This will continue for 5 seconds. If you press the MD button within this time, stg_restore_multiple() will be called. Reboot the device after the green status LED is turned on. If you do not press the button within the 5-second time window, the application will continue running. All related code is in the on_sys_init() event handler.
4. AggreGate.xtxt lists required A-variables.
5. There is an additional callback procedure in device.tbs — for callback_agg_convert_setting(). Examine the code — it "converts" between the UT setting (measuring time in half-second intervals) and the UT A-variable (measuring time in seconds). You can now see this procedure's usefulness — it allows you to store values differently compared to how they are perceived in AggreGate.
You will now be able to see newly created A-variables in the AggreGate Client (as shown on the screenshot below). Notice how all four A-variables appear on the Access Control tab? This is defined in the AggreGate configurator.
Notice also that each A-variable is displayed/edited differently:
•The Baudrate (BR) setting has a drop-down which shows all available values;
•The Generate Event (GE) setting as a checkbox because it is of the boolean type;
•The Unlock Time (UT) setting is just a plain value that is expressed in seconds (although the UT setting is in half-seconds).
•The Door State (DS) setting displays custom values "closed" and "opened" and is read-only.
Setting A-variables as we have them now are not doing anything useful on the device just yet. They simply exist as values. We will glue it all together later.