Would not the act of changing the battery clear/reset this bit. With no battery present what would sustain this information?
Bob K2TK On 6/24/2010 3:11 PM, Richard Dowling wrote: > The RTC IC has a low voltage detector which sets a bit in the seconds > register. Thus (from the IC data sheet): > > 8.5 Voltage-low detector and clock monitor > The PCF8563 has an on-chip voltage-low detector. When VDD drops below Vlow the > VL bit (Voltage Low, bit 7 in the Seconds register) is set to > indicate that reliable > clock/calendar information is no longer guaranteed. The VL flag can > only be cleared > by software > > So it's easy, just software ;-) > > Richard > KL0DR > > At 10:43 AM 6/24/2010, Brian Alsop wrote: > >> David Ferrington, M0XDF wrote: >> >>> Regarding the battery, is there a way to check it's voltage or >>> >> projected life - without taking the cover off and measuring it? >> >>> 73 de M0XDF >>> >> Reminds me of the same suggestion implemented in a few IBM prototype >> PC'S for the CMOS battery. They devised a circuit to go in and test it >> many times per day. Unfortunately, the act of repeatedly testing it >> removed enough energy to greatly shorten battery life. >> >> They dropped the idea. >> >> 73 de Brian/K3KO > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
