US 6,982,606 B2
Method and device for dynamically calibrating frequency
Chun-Hsiung Chen, Hsinchu (Taiwan); and Sheng-Ho Wang, Sijhih (Taiwan)
Assigned to Holtek Semiconductor Inc., Hsinchu (Taiwan)
Filed on Apr. 06, 2004, as Appl. No. 10/818,815.
Claims priority of application No. 92108484 (TW), filed on Apr. 11, 2003.
Prior Publication US 2004/0201403 A1, Oct. 14, 2004
Int. Cl. H03L 1/00 (2006.01)
U.S. Cl. 331—175 14 Claims
OG exemplary drawing
 
1. A method for dynamically calibrating a frequency comprising steps of:
(a) providing a first system frequency;
(b) obtaining a first parameter of timer counting number;
(c) providing a second system frequency;
(d) obtaining a second parameter of timer counting number if there is a frequency drift between said first system frequency and said second system frequency;
(e) obtaining a third parameter of timer interrupt interval by comparing said first parameter of timer counting number with said second parameter of timer counting number; and
(f) calibrating a frequency output according to said third parameter of timer interrupt interval.