Re:Why does the alarm clock snooze button give you nine extr...
by gmrple on Thursday October 31, 2013 @11:45AM
(#6647453)
BCD was my thought as well. For the uninformed:
http://en.wikipedia.org/wiki/Binary-coded_decimal
Here is an example with the page of the data sheet regarding how the snooze function works:
http://html.alldatasheet.com/html-pdf/9252/NSC/MM5387AA/168/...
When the alarm goes there is a 'latch' that is operational for 59 minutes. Pressing snooze does not turn this 'latch' off, it suppresses the alarm output for 8-9 minutes. Turning the alarm off is what resets the 'latch'.
Chips of this era worked on BCD - BCD ruled once upon a time, when people did things in FORTRAN...
I don't think that National Semiconductor deliberately sought to emulate the snooze time of analog alarms from a previous era, it just was do-able to do 8-9 minutes in available silicon.