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My requirement is to operate a PIC16F88 at 8MHz internal clock.

I'm trying to make sense of Flowcode's Project Options --> Configure options for "Oscillator Selection", which are:

EXTRC as Clock Out
EXTRC as Port I/O
INTRC as Clock Out
INTRC as Port I/O
EXTCLK as Port I/O
LP
XT
HS

Fairly obviously those options beginning EXT relate to an external clock, but I'm not clear about the usage of the INT ones, nor about LP, HT and HS.

Which should I select for my requirement?

Hello,

This wiki page should help.

http://www.matrixtsl.com/wiki/index.php ... Oscillator

LP - 32khz watch type crystal
XT - < 4MHz crystal
HS - >= 4 MHz crystal

as Clock Out - OSC1/OSC2 pins are used for the clock signals
as Port I/O - OSC1/OSC2 pins are in I/O mode

Benj wrote:Hello,

This wiki page should help.

http://www.matrixtsl.com/wiki/index.php ... Oscillator

Hello,

Yes, I saw that page earlier, where is says: "The configuration settings will also need to be edited from the default HS type oscillator to the IntOsc setting".

However (in V6 at least) there are two INT(ernal) options offered.

As per my question, the options listed are not clear to me. For instance, what's the actual difference between
'INTRC as Clock Out' and 'INTRC as Port I/O' for my purpose? Which should I choose and why?

I'm mainly using clocking for DELAY functions. I'm also using TMR0 for counting timer overflow interrupts.

Hi gtc,
The most common option is

gtc wrote:INTRC as Port I/O'

This frees a pin to be used as a general purpose input or an output.
In the case of 16F88 it's RA6.

gtc wrote:INTRC as Clock Out

just uses a pin as the osc/4.
So if internal osc is 4MHz there will be a 1MHz present on the pin, so it cant be used as I/O
I guess its handy for checking if osc frequency is correct.
I also guess it could be used for clocking other external components.

Martin

Thank you for explanation.