MSF clock module

[Archangel]

Will the pic recognise 2.1v as a logic 1, or will I need to amplify this to 5v to drive the pic?

Hi John, I do not think it will @ 5v as 2.1 is less than 1/2 way, but if you operate a PIC on 3.3v, then I would say yes. Check Microchips web site for PICs made to operate at that voltage.

[cunninghamjohn]

Thanks again for the replies on this subject. 'Derryck', i agree with your comments that it is a useful learning aid but nothing more. It would be easy enough to make a clock which was manually set and then incremented the minutes via MSF but im no longer satisfied with that idea and want to do something a little more sophisticated.
I have no experience with RTC chips, so cannot comment on the use of those. Perhaps some research is required. I do however want to keep the hardware as simple as possible, and preferably use 'junkbox' components. I do not yet know whether the MSF signal will be reliable enough not to need a backup clock.

Thanks for your comments Joe. The pic did not work with 2.1v pulses, so as it stands i am running the MSF module from a single 1.5v cell and 6v for the pic. I am using a simple common emitter amplifier to convert the pulses to logic levels (inverted of course)

Just as a matter of interest, I tried this program

pause 1000
N VAR WORD
M VAR BYTE
START
PULSIN PORTB.2,1,N
LET M=N/200 ; so that M fits into a byte variable
LCDOUT $FE,1,#M


GOTO START

This displayed the pulse lengths in mS/2. The LCD display gives 248 for the minute pulse, 98mS for a logic 1 and 47mS for a logic 0. ( my 4MHz clock for the pic must be out) This time the pen and paper exercise gave me the time and date information, so im pleased with the results so far.