CCS Function Parameter "us()"

[johnl]

The example given for the setup_psmc() function uses "us(100)" and "us(25)" for the 4th and 8th parameters. I searched the CCS manual and well as the 16F1788 header file and didn't find any reference. I assume they stand for 100 and 25 microseconds. Could someone point to a definition?

[temtronic]

OK, I've got a headache just tryin to look at the datasheet but I'm thinking they might be the 'deadband control' timings ?
Section 25.4, page 256.......

I'm sure some prof could write a book and a 3 month course on just THIS peripheral of the PIC !!!


Jay

[Ttelmah]

us, is a #define at the start of the code:

#define us(time) (int16)(time*(getenv("CLOCK")/1000000))

So it is just an int16 number of clock cycles needed for the particular number of microseconds. So with (say) a 20MHz clock, 10uSec, needs a value of 200 clock cycles.

The manual says the 4th and 8th parameters are 'period_time', and 'fall_time'.

Then if you look further down it says that these are in 'ticks' (of the master clock). Hence the define to work these out for you.

[johnl]

Ttelmah, did you reverse engineer that macro, or is it actually hiding in the documentation somewhere? I couldn't find it.

[Ttelmah]

It's in the example code....
Just after the processor include, and clock setting.

[johnl]

Here's the example from the manual which doesn't define the macro.
Where is the better example?

[Ttelmah]

It's in the examples directory....
Three examples to setup as a simple PWM, complementary PWM etc..

The bits in the manual are code 'snippets', not the actual examples. You can't compile the stuff in the manual, without all the other stuff (processor file, includes etc.). The actual examples show how to use the peripheral.

I'll repeat the old advice.
CCS required 'paperwork':

Manual
Chip data sheet.
Processor include file.
Examples/drivers.
Readme.

[johnl]

Silly me. I actually believed the statement "Example Files: None" in the manual!

Thanks to all who responded.

[Ttelmah]

I just updated my post while you were typing.

I don't know why the manual says 'none', but just about everything does feature in the examples, even if not specifically.