ABSTRACT
The OST func tion counts os cil la tor pulses on the OSC1/CLKIN pin. The coun ter starts in cre ment ing af ter the am pli tude of the sig nal reaches the os cil la tor in put thresh olds. This ini tial de lay al lows the crys tal os cil la tor or res o na tor to sta bi lize be fore the de vice ex its the OST de lay. The length of the time-out is a func tion of the crys tal/res o na tor fre quency. For low-fre quency crys tals, this start-up time can be - come quite long. That is be cause the time it takes the low-fre quency os cil la tor to start os cil lat ing is lon ger than the power-up timer's de lay.
