ccs compiler with pic12ce674?

Has anyone used the CCS C compiler with the PIC12CE674?

I'm having difficulty getting out of the starting block with a simple 
program (attached).

The chip is supposed to be set up to run on the internal oscillator (at 
4MHz) with the OSC2 pin set as an IO line, no MCLR pin input (MCLR pin used 
as an IO line), and with AN0 and AN1 used as analog inputs.  I've verified 
the fuse settings to be 0x3f74 and have verified this value in the hex file 
and in the device after programming.  Basically, GP0 (AN0) and GP1 (AN1) are 
analog inputs and GP2 (T0CKI), GP3 (MCLR), GP4 (OSC2), and GP5 (OSC1) are 
all discrete outputs.

When I run the program, all I see is a flatline high on MCLR and a flatline 
low on GP4.  I also tried setting the oscillator mode to internal oscillator 
with clock out on GP4 (OSC2).  When I ran that program, I see a nice, clean 
1MHz output on GP4.

Anyone have any idea what I'm doing wrong?

Thanks.

Dave

--- code follows ---

// test12c2674.c contents :
#include "C:\Projects\PicC\projects\test\test12ce674.h"

short toggleState;      // on or off state of digital output indicators

#ZERO_RAM
void main()
{
   toggleState = FALSE;

   set_tris_a(0x03);       // a0, a1 are ins (should be analogs); others 
outs
   setup_adc_ports(AN0_AN1_ANALOG);
   setup_adc(ADC_CLOCK_INTERNAL);
   setup_counters(RTCC_INTERNAL, RTCC_DIV_1);

   while(true)
   {
      if(toggleState)
      {
         output_high(PIN_A4);
         toggleState = FALSE;
      }
      else
      {
         output_low(PIN_A4);
         toggleState = TRUE;
      }

      delay_ms(250);
   }
}

// test12ce674.h contents:
#include <12CE674.h>

#device adc=8
#use delay(clock=4000000)
#fuses NOWDT, INTRC_IO, NOPROTECT, NOMCLR

I'm not surprise that you see MCLR high. You don't initialize it to anything
and the GPIO register bits are undefined on power-up.

Have you tried running this in the MPLAB simulator? Make sure you are looping.
Make sure your bit toggle statements are being executed.

Possible culprits:
>   while(true)
>

I notice that other places, you use TRUE and FALSE. The true in the while
statement is lower case. C is case-sensitive. I assume there's a
#define true 1
somewhere in an include file, but I don't know that for a fact. If it some
leftover variable, then your
#ZERO_RAM
directive probably set it to 0 and nothing in your loop gets executed.

Another possible culprit is the delay_ms function. I have no idea if it's
implemented with a  timed loop or  uses a hardware timer. You might want to
make sure it actually completes.

To see if your loop is actually being executed, you might try initializing
toggleState to TRUE so GP4 gets set high the first time through. Or initialize
GP4 to 1 before entering the loop and see if it goes low the first time
through.

"starfire" <starfire151@cableone.net> wrote in message news:<10pd9t1almce7fa@corp.supernews.com>...
> Has anyone used the CCS C compiler with the PIC12CE674?
> 
> I'm having difficulty getting out of the starting block with a simple 
> program (attached).
> 
> The chip is supposed to be set up to run on the internal oscillator (at 
> 4MHz) with the OSC2 pin set as an IO line, no MCLR pin input (MCLR pin used 
> as an IO line), and with AN0 and AN1 used as analog inputs.  I've verified 
> the fuse settings to be 0x3f74 and have verified this value in the hex file 
> and in the device after programming.  Basically, GP0 (AN0) and GP1 (AN1) are 
> analog inputs and GP2 (T0CKI), GP3 (MCLR), GP4 (OSC2), and GP5 (OSC1) are 
> all discrete outputs.
> 
> When I run the program, all I see is a flatline high on MCLR and a flatline 
> low on GP4.  I also tried setting the oscillator mode to internal oscillator 
> with clock out on GP4 (OSC2).  When I ran that program, I see a nice, clean 
> 1MHz output on GP4.
> 
> Anyone have any idea what I'm doing wrong?
> 
> Thanks.
> 
> Dave
> 
> --- code follows ---
> 
> // test12c2674.c contents :
> #include "C:\Projects\PicC\projects\test\test12ce674.h"
> 
> short toggleState;      // on or off state of digital output indicators
> 
> #ZERO_RAM
> void main()
> {
>    toggleState = FALSE;
> 
>    set_tris_a(0x03);       // a0, a1 are ins (should be analogs); others 
> outs
>    setup_adc_ports(AN0_AN1_ANALOG);
>    setup_adc(ADC_CLOCK_INTERNAL);
>    setup_counters(RTCC_INTERNAL, RTCC_DIV_1);
> 
>    while(true)
>    {
>       if(toggleState)
>       {
>          output_high(PIN_A4);
>          toggleState = FALSE;
>       }
>       else
>       {
>          output_low(PIN_A4);
>          toggleState = TRUE;
>       }
> 
>       delay_ms(250);
>    }
> }
> 
> // test12ce674.h contents:
> #include <12CE674.h>
> 
> #device adc=8
> #use delay(clock=4000000)
> #fuses NOWDT, INTRC_IO, NOPROTECT, NOMCLR

The GP3 pin is equivalent to an open collector output (technically
it's an open drain, but I'm old school). I'm not sure what the default
state of that pin will be after a reset, but I don't see you clearing
it anywhere in your code. Do you have a pullup resistor on the GP3
(RA3 in CCS) pin? I've gotten burned more than once by forgetting that
it needed one.

I've had problems with CCS IO setup functions in the past. They tend
to make assumptions about the order you will set up things, and so
sometimes don't clear or set a bit you would expect them too. There is
a warning in the 12CE674 datashet about GP4 comes up as an analog
input after reset. Perhaps setup_adc_ports isn't setting up ADCON1
correctly. I'd look at the assembly code listing for that function
call and see what the code is really doing. You could also check to
see if the pin is really an output, by connecting a 1K resistor from
the pin to the pluss side of your power supply, if the pin doesn't
look like a nice solid low, it's probably configured as an input.

CCS produces tight code, but I have a few problems with it. They use
different names than Microchip does, which makes looking stuff up in
the Microchip datashets a chore. Their io setup functions are often
buggy. In their defense they support a whole bunch of different chips
which tend to have very subtle differences.

If you're new to pic development, you might want to try a simple blink
the LED program on a different pin, just to make sure your development
environment is working.

Mark

On 14 Nov 2004 07:05:11 -0800, mhahn@hvc.rr.com (mark hahn) wrote:

>...Perhaps setup_adc_ports isn't setting up ADCON1
>correctly. I'd look at the assembly code listing for that function
>call and see what the code is really doing....

This is precisely why I never use those type of functions in the CCS
library.  I use the CCS compiler for midrange PIC development, but I
do all my own I/O setup and initialization by accessing the setup
registers directly.  It looks a lot like assembly language, but at
least I know what it is doing.


-Robert Scott
 Ypsilanti, Michigan
(Reply through this forum, not by direct e-mail to me, as automatic reply address is fake.)

Many thanks to those that have replied.  I've implemented all your 
suggestions but the problem remains.

I modified the program to only toggle pin 5 (PIN_A2).  I initialized the 
output to a high state before the loop.  When I checked the output bit with 
a logic probe, it shows as an open.  I pulled it to high through a 10K 
resistor and it shows as a high then.  Pulling it low shows as a low. 
Apparently the initialization is not working correctly.

I've printed the assembly output and will code it into MPLAB to check 
operation.  I will post the results but I probably won't be able to get at 
it until late this week due to work.  I've also run into the inevitable 
program, test, erase cycle bottleneck (I only got 3 of the erasable parts so 
tests have to wait for the erase cycles :)  )

I found in the datasheet where it specifies that the PIN_A3 (pin 4, the MCLR 
input) can only be used as an input.


"Gary Kato" <garykato@aol.com> wrote in message 
news:20041113231015.08096.00000667@mb-m07.aol.com...
> I'm not surprise that you see MCLR high. You don't initialize it to 
> anything
> and the GPIO register bits are undefined on power-up.
>
> Have you tried running this in the MPLAB simulator? Make sure you are 
> looping.
> Make sure your bit toggle statements are being executed.
>
> Possible culprits:
>>   while(true)
>>
>
> I notice that other places, you use TRUE and FALSE. The true in the while
> statement is lower case. C is case-sensitive. I assume there's a
> #define true 1
> somewhere in an include file, but I don't know that for a fact. If it some
> leftover variable, then your
> #ZERO_RAM
> directive probably set it to 0 and nothing in your loop gets executed.
>
> Another possible culprit is the delay_ms function. I have no idea if it's
> implemented with a  timed loop or  uses a hardware timer. You might want 
> to
> make sure it actually completes.
>
> To see if your loop is actually being executed, you might try initializing
> toggleState to TRUE so GP4 gets set high the first time through. Or 
> initialize
> GP4 to 1 before entering the loop and see if it goes low the first time
> through.
>
>
> 

Many thanks to those with suggestions.

The cause of the problem was the UV erase cycle on the eprom version of the 
PIC.  The oscillator/calibration value was also erased.  When a default 
value was loaded during programming, the program executed as expected.

Dave

"starfire" <starfire151@cableone.net> wrote in message 
news:10pd9t1almce7fa@corp.supernews.com...
> Has anyone used the CCS C compiler with the PIC12CE674?
>
> I'm having difficulty getting out of the starting block with a simple 
> program (attached).
>
> The chip is supposed to be set up to run on the internal oscillator (at 
> 4MHz) with the OSC2 pin set as an IO line, no MCLR pin input (MCLR pin 
> used as an IO line), and with AN0 and AN1 used as analog inputs.  I've 
> verified the fuse settings to be 0x3f74 and have verified this value in 
> the hex file and in the device after programming.  Basically, GP0 (AN0) 
> and GP1 (AN1) are analog inputs and GP2 (T0CKI), GP3 (MCLR), GP4 (OSC2), 
> and GP5 (OSC1) are all discrete outputs.
>
> When I run the program, all I see is a flatline high on MCLR and a 
> flatline low on GP4.  I also tried setting the oscillator mode to internal 
> oscillator with clock out on GP4 (OSC2).  When I ran that program, I see a 
> nice, clean 1MHz output on GP4.
>
> Anyone have any idea what I'm doing wrong?
>
> Thanks.
>
> Dave
>
> --- code follows ---
>
> // test12c2674.c contents :
> #include "C:\Projects\PicC\projects\test\test12ce674.h"
>
> short toggleState;      // on or off state of digital output indicators
>
> #ZERO_RAM
> void main()
> {
>   toggleState = FALSE;
>
>   set_tris_a(0x03);       // a0, a1 are ins (should be analogs); others 
> outs
>   setup_adc_ports(AN0_AN1_ANALOG);
>   setup_adc(ADC_CLOCK_INTERNAL);
>   setup_counters(RTCC_INTERNAL, RTCC_DIV_1);
>
>   while(true)
>   {
>      if(toggleState)
>      {
>         output_high(PIN_A4);
>         toggleState = FALSE;
>      }
>      else
>      {
>         output_low(PIN_A4);
>         toggleState = TRUE;
>      }
>
>      delay_ms(250);
>   }
> }
>
> // test12ce674.h contents:
> #include <12CE674.h>
>
> #device adc=8
> #use delay(clock=4000000)
> #fuses NOWDT, INTRC_IO, NOPROTECT, NOMCLR
>
>