PERIPHERAL MODULE DISABLE

[blowtorch]

Are there any CCS functions for using this feature? I did search the forum and found one post where registers for a specific chip were documented. Also looked the the chips .h file to check if the PMD registers were defined in any way. No luck.

Something like disable_module(FVRMD) to turn off the FVR module would be useful.

Or does one just address the PMD registers and set the bits manually Microchip / HiTech style?

[Ttelmah]

In most cases the individual peripheral enables, have disable defines in the .h file. So for instance the setup_adc function has as one of it's options ADC_OFF. This turns off the particular peripheral.
However to use the PMD, just generate the registers. Look in this thread:

<https://www.ccsinfo.com/forum/viewtopic.php?t=55498>

Shows how to disable all the peripherals. Obviously you can leave the ones you want enabled.

Note carefully the comment from Jeremiah on this. Problem is that PMD leaves you having to re-configure the peripheral when you re-awaken, so it doesn't seem to actually gain anything over just turning the peripheral off....

So, yes for the PMD functions, you just access these directly.

[newguy]

[blowtorch]

Thanks - I thought it would come to defining the registers and writing them directly to disable the various peripherals. So be it.

I expect at some point we will probably see some new commands appearing in CCS to exploit PMD.

TTelmah thanks for the heads up re re-configuring the peripherals. I guess it comes down to how much power is actually saved if completely disabling a peripheral as opposed to turning it off. Basically in my application I have a soft power off function, so I have to completely re-initialise everything on "power up" anyway.

[diode_blade]

Just doing a project now with 18F67K40 I added this to device header file.
Hope this helps.
Dave

[Ttelmah]

Yes.

The 'silly' thing is that on a lot of the modules, the 'off' function in the module already saves all the power. On the ADC for example, provided it is being clocked from it's internal clock it goes fully off. The key though is that if it is set to use the CPU clock, the circuitry that handles this remains enabled, and it is this that can result in a little power being drawn. The PMD disable, stops these clocks as well.
Now modules that don't have their own enables in the module itself, are things like the FVR, input change notification, & input capture. In these cases PMD is brilliant.
However it is worth saying that SIDL may well be better. Most of the PIC24 peripherals have an SIDL bit, which if set, makes the peripheral _automatically_ stop, when the chip goes to idle. This is a much more convenient way of having all the things you don't want running stopped for you when you sleep (might be worth investigating....).

I'd sit down and draw a list of the modules you want to keep running. Then generate bit pattern defines for each of the PMD registers to give these. Then do the same for all the patterns needed during normal operation (it is quite common to find quite a few modules never need to be turned on). Then your sleep can load all the disabled patterns before triggering, and on wake up you load the running patterns, and re-configure the peripherals. Hurrah!...

[blowtorch]

Thanks Gents