Ive tested the timing by turning by turning on and off 1 LED at equal intervals using timer0 for on and timer1 for off: I'm using pic18F242.. and I've used for RC oscillator first 1 50k resistor @ 39pf ceramic capacitor there was a long pause after 2 ON OFF cycle ( ON OFF ON OFF then a long PAUSE equal to the interval of 1 on or off ). contineously I then change the resistor to 10K... and this time a long PAUSE happens after 8 ON OFF cycle... I have reason to beleive that the code works correctly cause it turned on and off the LED as expected.. so this pauses must have something to do with the resistor capasitor pair.. what could be the cause of this pauses... Is there a resistor capacitor pair that the microcontroller works reliably.. I read somewher that there is an RC table values for different frequency in the datasheet but I could not find it for this particular PIC... hope anyone have an IDEA... "Jinx" wrote in message news:0c4901c6dd3a$410c61d0$0100a8c0@ivp2000... >> is the computation similar to that of a 555 timer in astable op... > > It's linear > > http://home.clear.net.nz/pages/joecolquitt/0f84rc.html > > I've no idea if that graph is applicable to newer PICs, but > 10k + 100pF @ 5V is about the frequency for a 16F88, so > maybe the RC circuitry is pretty much the same as always, > as is WDT > > Some datasheets do have R and C vs Vdd tables. eg DS30487C > (16F88), Figures 19-11, 19-12, 19-13 > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist