Easy and Accurate Clocks without RTC IC

[shahidali55]

Is there any way someone can create a Roman black kind (one_sec.asm) of accurate tmr0 timer using picbasic?

[THE_RB]

Hi Paul, that is a very neat and professional implementation of my 1-sec system for PICBASIC.


Would you be interested in creating a PICBASIC version of my BTc Picsound playback to enable PICBASIC users to play their own speech etc on PICBASIC hardware?

I have released v2.0 of my BTc Encoder and would like to get some playback projects that in can list on my own page, pref in languages I don't use like PICBASIC and for micros I don't use.

www.RomanBlack.com/picsound.htm

[email protected] (remove the FURNITURE to email me)

[Terry]

Paul,
In one of you earlier posts on this thread, you mention that you use a 20ppm crystal, can you share your source for this crystal. All the crystals I have found have a 50ppm tolerance at 25 deg and then a another 50ppm over temperature or then a worst case frequency tolerance of 100ppm, I would like to stay away from using a TXCO and 20ppm would be the right amount of acceptable tolerance for my project.
thanks,
Terry

[paul borgmeier]

Paul,
In one of you earlier posts on this thread, you mention that you use a 20ppm crystal, can you share your source for this crystal. All the crystals I have found have a 50ppm tolerance at 25 deg and then a another 50ppm over temperature or then a worst case frequency tolerance of 100ppm, I would like to stay away from using a TXCO and 20ppm would be the right amount of acceptable tolerance for my project.
thanks,
Terry

Hi Terry,

I am not near my lab so I cannot check right now ... however, I know I got them at either Digi-Key or Mouser. I just saw this part http://www.mouser.com/Search/Refine....t=815-ABL-4-B2
and will check in my lab and confirm if that is what I used. Back when I posted this example I let my trial circuits run for months and found the tolerance to always be +/- 20ppm or less with the xtals I used. I will let you know here shortly.

[Ron Marcus]

I use the Abracon line. They have both SMT and through hole packages @20 ppm. They have some higher speed @ 10 ppm. Very reasonable, besides!

[gmglickman]

Shouldn't it HzTimer be initialized to $7A120 (dec500000), rather than to $7A12 (dec31250)? And incremented by the same $7A120 for 1/2 second.

[gmglickman]

Never mind; now I see you're dividing by $10.