There is an XOR gate (T0CKI XOR TOSE) that triggers the=20 prescaler/counter. It is designed to allow setting which edge of T0CKI=20 triggers the counter, but the following circuitry has no way to=20 distinguish which signal is actually changing. It works. Kerry On 10/13/2016 5:38 PM, David C Brown wrote: > If there are no transitions on the input how does toggling TOSE generate > pulses? > > On 14 October 2016 at 00:06, Kerry wrote: > >> I use a different trick. >> >> 1) Make sure no more pulses will occur on the input by making it an >> output or analog input. >> 2) Toggle the TOSE bit to generate pulses to the counter until it counts= .. >> >> Kerry >> >> >> On 10/13/2016 4:28 PM, Denny Esterline wrote: >>> Fuzzy memory says it was in one of the Tips 'n Tricks books. Run signal >>> though a AND gate, second gate input hooked to a digital output pin. >>> Connect another output pin to the counter input pin, - I think there wa= s >> a >>> resistor from the gate to the counter input to avoid contention. >>> In use- after count time, pull the control line to the AND gate low, th= en >>> clock the other pin while checking the count register. If you count how >>> many pulses it takes to see the count register change, and you know the >>> prescaler setting, a little math gets you to the value that was in the >>> prescaler register. >>> >>> >>> -Denny >>> >>> >>> >>> On Thu, Oct 13, 2016 at 12:37 PM, wrote: >>> >>>> Yeah, it seems to me you count clock cycles until you get an >> interrupt, >>>> then subtract that number from 255. That will give you the starting >>>> count of TMR0. >>>> >>>> >>>> Regards, >>>> >>>> Jim >>>> >>>>> -------- Original Message -------- >>>>> Subject: [PIC] Timer0 prescaler >>>>> From: David C Brown >>>>> Date: Thu, October 13, 2016 2:08 pm >>>>> To: "Microcontroller discussion list - Public." >>>>> >>>>> >>>>> ISTR an application showing how you could deduce the value in this >>>> register >>>>> (mid range PICS such as 'F88) but cannot find it now. Anyone help? >>>>> >>>>> -- >>>>> __________________________________________ >>>>> David C Brown >>>>> 43 Bings Road >>>>> Whaley Bridge >>>>> High Peak Phone: 01663 733236 >>>>> Derbyshire eMail: dcb.home@gmail.com >>>>> SK23 7ND web: www.bings-knowle.co.uk/dcb >>>>> >>>>> >>>>> >>>>> >>>>> *Sent from my etch-a-sketch* >>>>> -- >>>>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >>>>> View/change your membership options at >>>>> http://mailman.mit.edu/mailman/listinfo/piclist >>>> -- >>>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >>>> View/change your membership options at >>>> http://mailman.mit.edu/mailman/listinfo/piclist >>>> >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .