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Hi all:
I have been looking for information about what the period for Pulsout would be for an 8 mhz 16F88. I have a program that is working at 4mhz, but want to move it to 8mhz.
The servo I am using now responds now to pulsout from 90 to 250 but at 4MHZ...
At 8 mhz what would these values be? How does one think about this - I have no mental model for what is going on...
Thanks,
Tom
multiply your value by 2
Quote:
The resolution of PULSOUT is dependent upon the oscillator frequency. If a 4MHz oscillator is used, the Period of the generated pulse will be in 10us increments. If a 20MHz oscillator is used, Period will have a 2us resolution. Defining an OSC value has no effect on PULSOUT. The resolution always changes with the actual oscillator speed.
And if NO Osc is used as with the 16F88 internal??? I am running at 4mhz now, and have seen mention of how to run at 20mhz.. BUT what about 8mhz..
does a '100' at 4 mhz = a 50 at 8mhz? Or is it a '200' ? or is it linear?
TG
let's trim the above quote
So if you have '100' @ 4Mhz... you'll have '200' @ 8MHZ. Of course it's linear as the OSC definition don't change anything in the result.Quote:
If a 4MHz ... in 10us increments.
If a 20MHz ... 2us resolution.
It doesn't matter if you use the internal or the external one... must have some heartbeat somewher ;)
TG,
Don't forget to add:
DEFINE OSC 8 at the start of your program. This is needed to adjust other time dependent commands.
I also run my servos with 8 mhz. For PULSOUT do as MisterE says and multiply by 2. So, if your old servo range was 90 to 250 your new range will be 90*2 to 250*2. The servo will move the same number of degrees but with greater resolution.