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→Appendix B
== Appendix B ==
The following screenshot shows the emulated alarm signal, which is generated by the custom timer. It consists of a 1-second positive pulse. [[File:MISC-TN-015-timer-alarm-signal.png|thumb|center|600px|Fig. B1: Emulated alarm signal generated by the custom timer]] Each display is statically driven by a [https://www.onsemi.com/pub/Collateral/MC74HC595-D.PDF 74HC595] shift register in order to avoid multiplexing that would be detrimental for our purpose. [[File:MISC-TN-015-timer-refresh-alarm.png|thumb|center|600px|Fig. B1: Emulated alarm signal and latch clock when displaying 50.000]] Fig. B1 shows the emulated alarm signal (magenta) and the signal used to update the 7-segment displays when the timer reaches 50.000 (light blue). This signal is connected to the "latch clock" inputs of the shift registers so that all the displays are updated simultaneously. Turning on/off LED's is a very fast process, comparable with the propagation time of the shift register itself. Thus, it can be assumed that the displays show 50.000 within a few tens of nanoseconds after the rising edge of the latch clock. This is long before the assertion of the emulated alarm signal, proving the correctness of the timer implementation.
==Credits==
*Industrial automation image source: [https://www.freepik.com/vectors/technology Technology vector created by macrovector - www.freepik.com]
