PIC24HJ to PIC24EP pin mapping

[benoitstjean]

Compiler: 5.026
Device: From 24HJ256GP206 to PIC24EP512GP806

Hello,

I am currently using the 24HJ256GP206 device and I want to change to the PIC24EP512GP806.

All pins match (a few I just need to change port E to port G) but the ones that concern me the most are the following (because I am using them on the PIC24HJ and need them on the PIC24EP):

PIC24HJ
=====
Pin 31 == U2RX
Pin 32 == U2TX
Pin 33 == U1TX
Pin 34 == U1RX
Pin 39 == CLKIN
Pins 42-45 == EXT INT1-4

PIC24EP
=====
Pin 31 == RP100
Pin 32 == RP101
Pin 33 == RP99
Pin 34 == RP98
Pin 39 == RPi60
Pins 42-45 == RPi72-75

It's the first time I look at the PIC24EP-series and I'm not quite sure how to address this pin-mapping issue.

So, how do I tell the PIC24EP to configure its pins so that they have the same functions as the PIC24HJ?

I am currently reading the PIC24EP manual but I want to speed-up the process. If you can post code, that would be very helpful.

Thanks!

Ben

[Ttelmah]

You don't use RP numbers, but pin names.

So pin 31, is PIN_F4.

[benoitstjean]

Hi Ttelmah,

Ok, that seems pretty clear. Thanks so much.

As for the CLKIN pin, on my circuit I am using PIN 39 as the clock input because it's getting its clock from an external oscillator (FXO-HC735R-36.864). That clock feeds the master clock of an audio CODEC as well as the MCU.

On the PIC24H, it shows on the pinout diagram that PIN 39 is OSC1/CLCKIN/RC12.

On the PIC24E, it shows OSC1/RPi60/RC12.

So, maybe I am just confused with the terminology? It's true, I don't see any reference in my code for "CLKIN" but I guess I just took for granted that it was that word I should have used rather than OSC1?

In my header file, I have these two lines:

[benoitstjean]

Ok, so I did the pin mapping and it's almost compiling.... I still have two issues + the CLKIN from my previous post above:

First, in PIC24HJ header file, I have COMPARE_PWM and I use it here:

[jeremiah]

The error is telling you that you have an invalid pin. Did you do a pin_select statement for your PWM pin? All remappable peripherals require a pin_select statement(s) before their functions can be used.

D0 is a remappable pin and PWM requires remapping.
Also Pin35 (PIN_F6) is remappable, so you can put a remappable interrupt on there. (so another pin_select)

You should spend some time reading section 11.4 of your datasheet to understand the peripheral pin select. If you use other peripherals in this category you will need to map them as well. Tables 11-1 and 11-3 have all the input and output sources that must be remapped.

[benoitstjean]

Hi Jeremiah,

Thanks for the info.

But if you look at the PIC24H and PIC24E, the 'H' version has PIN 35 (F6) as U1RTS/SCK1/INT0/RF6.

Now if you look at the 'E' version, PIN 35 only says RP102/RF6. But if you look at PIN 46, it says INT0/RP64/RD0.

Then in the Microchip specs DS70616G, page 25, if you look at <TABLE 1-1 PIN I/O DESCRIPTIONS> and scroll down to the external interrupts (middle), it shows that INT 0 is _NOT_ a PPS pin but the others are.

So, although PIN F6 is a reprogrammable and D0 is reprogrammable, INT0 is stuck on D0 from what that table 1-1 tells me.

However, if you know how to remap INT0 to RF6, then please show me the code to do it because I have no clue.

As for D0 being a remappable pin and PWM requires remapping, I'm confused there as well. Why would I need to re-map the PIN D0 for the PWM when on both devices, PIN D0 is PIN 46? The remapping would only be for stuff like UART1 and such... but this is the pin itself.

Again, this pin mapping thing is new to me and I don't have the PIC with me, I just placed the order this morning. Now I'm just trying to recompile the code for the new PIC to see how it will react.

You seem to know what I am trying to do. Can you post the code? Because in all honesty, I don't know to remap an interrupt that is not remappable and how to remap pin D0 (46) to the same pin D0 (46).

Thanks again,

Benoit

[Ttelmah]

You can't remap fixed peripherals. That's the whole point of the word 'fixed'....

What you could do is put another interrupt on the re-mappable pin, if you are not using them all.

[benoitstjean]

But aren't there only 5 external interrupts (INT0-INT4)?

And as for Jeremiah's message regarding the PWM pin D0 that I am currently using, I don't see how this pin can be mapped to the PWM because it is the same on both PIC versions: D0 is PIN 46.

[Ttelmah]

There are a lot of other ways of generating an interrupt. You can (for instance), use 'input capture', to generate an interrupt each time an input counts, by using a timer, and having this reset on a count of 1. However if you want INT0, then this is fixed on the pin it is on.

There are two different PWM's on the more complex chip. The normal timer based PWM, and the separate high speed PWM module. The latter is setup using the setup_hspwm function, and uses fixed pins. The former is a relocatable peripheral. So effectively there are two PWM 1's. One the high speed one, and the other the traditional one. Both can be used at the same time. If you are using 'setup compare', you are using the timer based one, and this requires you to have selected the pin using #pin select....

The normal timer based peripheral is 'output compare', and on the old chip you were using OCx to generate this, and it is the equivalent OCx peripheral that you have to setup.

[benoitstjean]

Hi Ttelmah,

Ok, that's good to know that there are two different PWMs. Again, this is a new device to me.

However, I still don't understand how to re-map pin D0 (46) which I am already using to pin D0 (46)..... Or in other words, if I absolutely need to use #PIN_SELECT for PIN D0 for PWM 1, then what is the #PIN_SELECT I need to setup given that this is my PWM setup for the 24H:

setup_compare( 1, COMPARE_PWM | COMPARE_TIMER2 );
setup_timer2( TMR_INTERNAL | TMR_DIV_BY_1, Value );
set_pwm_duty( 1, (( Value + 1 ) / 2 ));


And getting back to your second reply to me, am I wrong to use the term CLKIN for the input clock on pin OSC1/RPi60/RC12? Should I have used the term OSC1 instead?

I guess clarifying these two issues will enable me to compile my code. I am receiving the parts today.

Thanks again!

Ben

[Ttelmah]

You are generating your PWM here using an output compare module. As I have already said this module's output pin is called 'OCx', with the 'x' being the number of the module being used (1 in this case). So you need to select OC1 to the pin you want. If you look at the output compare module block diagram (15-1), it shows the pin names used. On your old chip, you will see that PIN46, has OC1 on it (no mention of PWM you note).

#PIN_SELECT OC1=PIN_D0

On the clock it doesn't matter, except if you had looked at the oscillator diagram, you would see that the primary oscillator input pin is already fixed to the pin you want. 'CLKIN', could apply to so many other things (synchronous serial, timers, etc. etc..). The oscillator pins can _not_ be relocated, since they have to be working for the chip to actually boot, if an external oscillator is being used, so when you asked about relocating 'CLKIN', I asked 'of what'....

[jeremiah]

EDIT:
Looks like Ttelmah drank some good coffee this morning. Beat me by a few mins!

[Ttelmah]

It's late afternoon here, and I've spent the day traipsing many miles.
Searching shops for an old thermometer. Need one close to an original, so that I can re-manufacture the brass plate, and it'll look/fit correctly.
Visited something over 500 antique dealers today.
Collapsed into my chair, for some programming....

Anyway he seems to already be using all four of the re-locatable interrupts (look at his original post). Why, I don't know. Five separate external interrupts does seem OTT....

However input capture offers him loads more interrupts. You can program any of these the capture on either the rising or falling edge. Only extra overhead, is to make sure you read the buffer in the interrupt handler (or the interrupt can't be cleared).

[benoitstjean]

Ah! Gotcha! Ok so I guess the OC1 (Output Compare) is what confused me! Just tried it and it works!!!

When I say it works, I mean it now compiles without errors. I haven't received the PIC devices yet (sometime today) and then I am leaving for 2 weeks on holidays so I will try it physically upon my return.


As for INT0, the reason to use that one particularily is that all my PCB's are done and working with the PIC24H and I am using all 5 external interrupts. INT0 on the PIC24H is on different pin than on the PIC24E... that's like the ONLY different and of course, it's not remapable. It's not a big deal because it is only used to detect the presence of an SD card and the interrupt is fired upon insertions/removal.

When I do version 2, I will look into that pin to change it.


Now I guess my last question pertains to the OSC1/CLKIN/RC12 pin 39 on the PIC24H which is OSC1/RPi60/RC12 on the PIC24E.

I am getting my PIC clock (square wave) from an external source and it goes into PIN39. I thought that the OSC1/OSC2 pins were for the little 2-pin tin-can crystals tied between OSCa and OSC2 and for high-speed oscillators (square wave like mine), although I am still using PIN39, it's a "clock input" hence CLKIN.

So my question is on the PIC24E, since PIN39 doesn't say CLCKIN, will my 60MHz oscillator still work?

Thanks a million!

Ben

[jeremiah]