Problems with sleep and the ADC on the PIC 12CE674

[Leif Steinhour]

Hey:
I've got some code that's doing something screwy: it's driving Pin 6 (GP1) low even though I've set it a bunch of times to be an input and an analog one at that. The chip's mostly in sleep mode, but it's using WDT events to wake up, so it should just be restarting. I am using the right pointers, have the chip hooked up correctly (no shorts to ground!), set the ADC up right, etc. In the actual code I'm really pushing the chip (using both Timer0 and WDT and all the pins in various manners). Anyone had this same problem?

Here's the code:

#include <12CE674.h>
#device PIC12CE674 *=8 ADC=8


#include <math.h>

#use delay(clock=4000000)
#use fast_io(A)

#fuses INTRC,WDT,PUT,NOPROTECT,NOMCLR//,NOBROWNOUT // Need to fix this piece of it


#rom 0x7ff = {0x3494} // This is for a 12CE674 Device


#define VOLTAGE_CHANNEL 1 // Correct
#define MAXVOLTAGE 199 // This should correspond to 12.6 volts for an 8 bit A/D
#define MINVOLTAGE 141 // This should correspond to 9 volts for an 8 bit A/D
#define NINEpONE 143 // This should correspond to 9.1 volts for an 8 bit A/D
#define NINEpFIVE 168
//#define WATCHDOG_TIMER


#define THERM_CHANNEL 0
#define MAXTEMP 204 // This corresponds with 65 degrees, and let's the operator know he's about to die

#define GREENLED PIN_A2 // Correct
#define REDLED PIN_A4 // Correct
#define BULB PIN_A5 // Correct
#define BUTTON PIN_A3 // Correct

#define CONSTANT0 4080 // This defines the duty cycle for the LED

//#byte STATUS_REG = 03h

// Global Variables

int1 green_led_state=0, red_led_state=0;
int1 green_led_flash=0, red_led_flash=0;
int duty_cycle;
long dummy=0;
int constant=CONSTANT0;
int pressnumber;

// This receives the last A/D conversion
int value;

// This is the main counter for the pwm
int pwm=0, duty=0;

int1 start=0, lamp_on=0;

#INT_TIMER0
void PWMoutput()
{
pwm++;
if (pwm == 256) {
pwm=0;
if (lamp_on) { output_high(BULB); }
}

if (duty == pwm)
{
output_low(BULB);
}

if ((!start) && (lamp_on)) // Lamp has not been started yet
{
if (duty<duty_cycle) duty++;
}
} // End PWMoutput

void buttonpress()
{
if (!(input(BUTTON))) {
pressnumber++;
if (pressnumber>=3)
{
pressnumber=0;
}
delay_ms(100);
restart_wdt();
}
}

void sandman()
{
lamp_on=0;
output_low(BULB);
disable_interrupts(INT_TIMER0);
while (pressnumber==0)
{
buttonpress();
sleep();
}
}

void startbackup()
{
setup_wdt(WDT_1152MS);
enable_interrupts(INT_TIMER0);

set_tris_a(0x0B); // Setup the register as follows: 0b0001011 Correct (ones are inputs)

setup_adc_ports(AN0_AN1_ANALOG); // Set all of these pins as analog inputs
setup_adc(ADC_CLOCK_DIV_32); // Set the clock for the fastest mode, not that it matters



}

void flash_redgreen()
{
int i;

for (i=0; i<10; i++)
{
restart_wdt();
delay_ms(250);
restart_wdt();
delay_ms(250);
output_high(GREENLED);
output_low(REDLED);
restart_wdt();
delay_ms(250);
restart_wdt();
delay_ms(250);
output_low(GREENLED);
output_high(REDLED);

}
output_low(REDLED);
pressnumber=0;
sandman();
startbackup();
}



void flash_red()
{

int8 i;

output_low(GREENLED);

for (i=0; i<10; i++)
{
buttonpress();
restart_wdt();
delay_ms(100);
restart_wdt();
delay_ms(100);
restart_wdt();
delay_ms(100);
restart_wdt();
delay_ms(100);
restart_wdt();
delay_ms(100);
output_low(REDLED);
restart_wdt();
delay_ms(100);
restart_wdt();
delay_ms(100);
restart_wdt();
delay_ms(100);
restart_wdt();
delay_ms(100);
restart_wdt();
delay_ms(100);
output_high(REDLED);

}
pressnumber=0;
sandman();
startbackup();

}



main ()
{

byte value;
int i;

// Setup Pins

pressnumber=0;


set_tris_a(0x0B); // Setup the register as follows: 0b0001011 (ones are inputs)
setup_adc_ports(AN0_AN1_ANALOG); // Set all of these pins as analog inputs
setup_adc(ADC_CLOCK_DIV_32);


setup_timer_0(RTCC_INTERNAL); // This will give us overflows every 255 instructions, just fine for PWM work

setup_wdt(WDT_1152MS); // We have to set this afterwards so the prescaler does it's thing

enable_interrupts(GLOBAL);
enable_interrupts(INT_TIMER0);


output_high(GREENLED);
output_low(BULB);

delay_ms(100);
output_low(GREENLED);
output_low(REDLED);

restart_wdt();

delay_ms(100);
restart_wdt();

if (restart_cause() == WDT_TIMEOUT)
{
output_high(GREENLED);
output_high(REDLED);
restart_wdt();
while (1) {
delay_ms(100);
sleep();
}
}

// The interrupt turn ons were here...


// First, check to see if the temp is out of range. If so, go to redgreen flash routine


while (1)
{
buttonpress();
if (pressnumber==0)
{
output_low(REDLED);
output_low(GREENLED);
sandman();
startbackup();

set_adc_channel(THERM_CHANNEL);
value = read_adc();

if (value>=MAXTEMP)
{
flash_redgreen();
}
setup_wdt(WDT_1152MS);


}
restart_wdt();

set_adc_channel(VOLTAGE_CHANNEL);
value=read_adc();

dummy=constant/value;
dummy=dummy/value;

duty_cycle=dummy;

if (value<MINVOLTAGE) // We need to soft charge the battery
{
flash_red();
}

if (value>NINEpFIVE)
{
output_high(GREENLED);
output_low(REDLED);
}
else if (value>NINEpONE)
{
output_low(GREENLED);
output_high(REDLED);
}
else
{
duty_cycle=(duty_cycle/4);
restart_wdt();
delay_ms(250);
restart_wdt();
delay_ms(250);
restart_wdt();
output_low(REDLED);
delay_ms(250);
restart_wdt();
delay_ms(250);
restart_wdt();
output_high(REDLED);
}


if (pressnumber==1)
{
lamp_on=1;
}
if (pressnumber==2)
{
duty_cycle=duty_cycle/2;
}

restart_wdt();
delay_ms(250);
restart_wdt();
delay_ms(250);
restart_wdt();
delay_ms(250);
restart_wdt();
delay_ms(250);
restart_wdt();


// end main loop


}
}
[/code]
_________________
To watch plants grow, blink more slowly.

[PCM programmer]

[Leif Steinhour]

I meant "continuing" rather than "resetting". I knew about that, and the code is planned accordingly. As per your request, here's the code in the correct format:

[Ttelmah]

You say that the code is written to handle the fact that a watchdog 'continues', from a sleep, but it doesn't really look like it is.
As it stands, the code will have sit looping in the sleep, delaying 100mSec, then going to sleep, waking, executing the allready fetched loop instruction, delaying 100mSec, sleeping again etc..
If you want the chip to restart from the watchdog, you need to sit in a loop for a couple of seconds or more (remember the watchdog 'times' are very approximate), without the sleep instruction, which will then force the watchdog, to trigger a restart. Simply coding 'while(true);' will force a watchdog restart if it is enabled. Otherwise, if you want it to continue (which you then seem to show), code with a layout like:
initialise.
sleep
dummy instruction (delay_us(1))
If you get here the chip has woken from the watchdog.

Best Wishes

[PCM programmer]

A couple things before we go any further:

1. What is the version of your compiler ?
This will be a number like 3.188 or 3.212, etc.
You can find it at the top of your list file (.LST)
after you compile a program.

2. You have tons and tons of code like this:

[Leif Steinhour]

PCM 3.137 on the compiler. I'll definitely take advantage of the #USE directive, that sure makes things cleaner.
_________________
To watch plants grow, blink more slowly.

[Leif Steinhour]

[Mark]

[Leif Steinhour]

Surre, that's definitely a typo and a problem, thanks for bringing that to my attention. Having said that, it will skip over that line as it goes past, which is unrelated to the problem I'm worried about: it's grounding AN1 and shouldn't be. I'm pretty sure it shouldn't be having a problem with that line, and yet it is.
_________________
To watch plants grow, blink more slowly.

[PCM programmer]

My suggestion is to make a small program that only tests for
the AN1 problem. If you still can't make it work, then post
the test program.

[drh]

You need to delay after changing the ADC channel. Try 20uS.
_________________
David

[Leif Steinhour]

Thank you, that was it. If anyone else has this problem, the symptom is an intermittent tie to ground.
_________________
To watch plants grow, blink more slowly.