Switch from PCI16F1938 to PIC16F18857 not working

[edbfmi1]

Hello all,
Accidentally posted this is the wrong forum yesterday. Sorry about that.

I have a project that requires more memory, so I switched from a PIC16F1938 to a PIC16F18857.
Before I added the new code I wanted to make sure that the processor change would work.

I am using MPLAB X Ver 6.20 and CCS PCM Version 5.118.

Like I said before the only change I made to my existing program that works was the Header File. Everything else is the same.

It looks like the program is running extremely slow.

Here are the only changes I have made to the program. I simply remarked out the header file for the old processor and added the new header.

Any help would be appreciated.

[temtronic]

my 'gut' is telling me the new PIC's clock(4MHz) may not be running so it's using the 'secondary' RC clock( low speed)

You should cut a '1Hz LED' program and confirm the new PIC is operational.

Also see if the new PIC has PPS pins. If so, you'll need more code to set them up properly.

[Ttelmah]

Key absolutely huge difference.

The new chip is a PPS chip. You _have_ to _PIN_SELECT_ the pins for
the peripherals.
Look at the sticky at the top of the forum for how to use PIN_SELECT.
However your I2C looks to be software so not using the peripheral. What
other peripherals do you use???

CCS needs you to tell it where the peripherals are connected on PPS chips.
It won't correctly handle the TRIS settings for the peripherals without
this.
This also depends a little on what compiler version you have On some
chips with recent compilers the compiler will infer the PPS settings,
however it is always safer to do them yourself

This chip also has programmable slew rate control, which will cause
issues with the I2C, unless you set the pins to support fast operation.
Same sticky has details about this.

[edbfmi1]

Thank you all for the input.
I understand what you are saying regarding the PIN_SELECT.

The reading and writing of the External EEprom is working.
It is just the clocking of the pic that is running extremely slow.

I think I am setting up the external oscillator incorrectly and am not sure what I need to do to tell it to use an external 4Mhz oscillator.

[gaugeguy]

#fuses is processor specific. You must manually change it to match the new processor.

#use delay can be used to set up the clock input without needing the #fuse directive.

#use delay(clock=4M, type=crystal)

[edbfmi1]

Hello again,
I am still struggling with getting the Oscillator to work properly.
I am using an external 4Mhz Ceramic Resonator
Trying to set it up to give me a 1msec interrupt on TMIMER_0.
Everything that has worked in the past does not work now since this is a PPS chip.
Am I missing something with setting up the PIN_SELECT to use the external processor?
Thanks

[temtronic]

hmm, ceramic resonator is not the same as a crystal with 2 caps. That may be your problem. You'll need to read the mfr spec for how to get it working with the PIC.

Just cut SIMPLE code ,like the 1Hz flashing LED program, post it here so others can see what you're doing.

edited...
looked at datasheet. that PIC does have internal oscillators, so you could use one of them,at least for basic testing purposes.If your project needs super accurate timing, then an external xtal/2caps is best.

[edbfmi1]

Hello again.
Per temtronic's suggestion I wrote a simple LED flashing program.
It uses Timer0 setup for a 1ms interrupt and TimerCounterPreset to set how often the LED output is toggled.
The first program was with the PIC16F1938 and it works.
When TimerCounterPreset is set to 1000 I get a 1secong LED pulse.
Here is the code.

[temtronic]

by simple 1Hz LED program
I mean,something like this....


main()
do
output_toggle(LED);
delay_ms(500);
while(true)

...
it should flash the LED at 1Hz rate, forever.

I 'think' both your programs require a 'delay_cycles(5)' or similar as the last line in main() otherwise the PIC automatically goes to sleep ?
To me, In effect there is no real 'main' program... you set some bits then ????
Pretty sure Mr. T or others will reply soon, well, depending on where Mr. Sun is in their part of the World.

[gaugeguy]

In the PIC16F1938 Timer0 is 8 bit.
In the PIC16F18857 Timer0 is 16 bit.

[edbfmi1]

Ok,
Super simple program.

[temtronic]

Great, now you know why the dinosaur likes 'super simple'. You've proved it's NOT a 'clock' issue, that the hardware attached to the PIC works and the compiler is 'happy' with your code......

Since the Timer0 can be either 8 or 16 bits, you'll have to configure for that and there's an 'enable' bit that needs to be 'set'. have a look at the PIC.HDR file to see what's involved.....

[Ttelmah]

SETUP_TIMER_0(T0_DIV_32|T0_INTERNAL|T0_8_BIT); // 4MHz Setting

General comment, don't use the RTCC settings. these are for reverse
compatibility only. They say:

// The following are provided for compatibility
// with older compiler versions

Use the T0 settings instead. The timer0 on the older chip was only an
8bit timer. Timer0 on the newer chip can be programmed to be 8bit or 16bit.
The above T0 setting sets it to 8bit.