CAPTURE Mode

When the key “c” is entered, the terminal window will appear as shown in the following figure

Figure 1. Terminal Window when Tamper Enabled in Capture Mode

The device will enable tamper detection in capture mode (for more details, refer Modes of Operation) and enable the RTC

After enabling the RTC, the firmware configures the DMA for getting the timestamp from the TIMESTAMP register without CPU intervention; the clock starts counting at an interval of 1 second

Set the mode flag and the previous mode flag as SET_TO_CAPTURE, to keep track of the current operating mode of tamper and previous mode of tamper

The device goes to sleep. However, the RTC will still be running internally.

Now, the firmware will be waiting for the tamper input in the main function. In this condition the user also has the provision to change the input mode (only after the first tamper condition is detected).

Here, the Tamper condition can be generated by pressing and leaving the user switch SW0 (which is connected to the tamper input pin)

When the tamper occurs, the following action happens:

Get the current time from the clock register and set the alarm after five seconds and Set the tamper flag
Now the time value is available in the structure variable tamper_time. It prints the time on terminal window as shown in the following figure.
The format in which the time is printed on the terminal window, is given as follows

[HH:MM:SS] = [12:00:00] PM

Figure 2. Terminal Window when Tamper Callback occured in Capture Mode
Display the tamper occurred time on the LCD as shown in the following figure and enable the timer module with specified overflow value (user configurable) for blinking the SLCD backlight by toggling the port pin connected to it

Note: The LCD displays only Hours: Minutes as 12:00 PM (for seconds, view the terminal window)

Figure 3. LCD Screen when Tamper Occurred in Capture Mode
In addition to the above, it also writes the tamper Timestamp value to the RWW EEPROM section for keeping track of the tamper occurance
The application is configured to store only 128 entries of time. When 128 entries are filled the firmware will display the error message shown in the following figure.

Figure 4. Memory Full Error Message