Instant Interrupts - Revisited

[Darrel Taylor]

The difference is that on the 4520, there is only 1 interrupt source for the Comparator module. A change in either comparator will cause an interrupt to the same handler.

There are other chips that have individual interrupt flags for each comparator, but not the 4520.

So you need to use the CMP_INT, on that chip.
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[duncan303]

Hi Darrel,

Thanks for reply, I had slowly worked my way towrds that.

for th 18F45K20 Migration
The comparator is no longer controlled by the
CMCON register and each comparator now has it’s
own control register, CM1CON and CM2CON. The
functionality of the bits has also changed.

there is a section that confirms the observations made about the registers, so it really does always boil down to RTFD, but reading is sometimes not enough if you suffer from word blindness, anyway it gave me the opportunity to say thankyou for your routines which I intend to use.

Duncan.

Furthermore if everybody read and fully "understood" the datasheets this forum would die.

[Darrel Taylor]

... thankyou for your routines which I intend to use ...

Grrreat! Hope the rest works out OK.
If not, let me know.

Furthermore if everybody read and fully "understood" the datasheets this forum would die.

Or, then we could actually talk about the real purpose of this forum.
Programming with PicBasic Pro.
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[Wirecut]

Hi Darrel,

this is my first post on this comunity. First of all I would thanks for the fantastic DT_INTS-14.bas background PWM routine.

I have uset your SW on a 16F628 in order to drive some LED with different brightness an WORK PEFECTLY. Darrel YOU ARE GREAT!!!!!

Now I need to use a potentiometer so set at run time the brightnes value for the LEDs, and after reading tons of html page and googled for hours, I have the founded suspect that the PBP instruction POT and RCTIME do not work with DT_INTS-14.bas.

Can you please confirm?

Ciao

Leo

[tenaja]

Leo,
Any time you have a routine or command that counts time, an interrupt will cause the timing to be off. Since the POT command times the discharge time of a cap, an interrupt in the middle of it will cause the command to give you a faulty reading when it is resumed.

There are several options;
--turn off the interrupts just before your POT command (and any other timing-specific command), and restore them just after.
--write yourself a home-made "pot" command, and use it inside the interrupts (but this only works if your interrupts are high frequency.)
--use a "real" a/d converter, either one in the PIC or off the chip.

[Wirecut]

Many thanks tenaja for your prompt reply.
Ciao
Leo

[Darrel Taylor]

Many thanks tenaja for your prompt reply.

My sentiments, exactly.
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