18F6527 Internal A/D converters

[bill conley]

For the 1st time ever, I'm having trouble reading the internal A/D converter of a PIC??
- I'm using the 18F6527 @ 10Mhz
- #device ADC=10
- setup_adc_ports(ALL_ANALOG);
- setup_adc (ADC_CLOCK_INTERNAL);
- All chanels return 1024?????

Code looks something like this;
set_adc_channel(0);
delay_us(100);
temp_ad = Read_ADC(); //
delay_us(200);
fprintf((COMM_PORT1),"+3Vdc: %lu\r",temp_ad);

set_adc_channel(1);
delay_us(100);
_dvdc_ = Read_ADC(); //
delay_us(200);


Thanks!

[PCM programmer]

Post your version of the compiler.

[bill conley]

Sorry...it's 3.249

[Guest]

Did you check the NOLVP fuse?

[bill conley]

Oh Gee, I wonder who this is???

- #fuses NOLVP,HS,PROTECT,NOWDT,PUT,BROWNOUT//,BORV45

[PCM programmer]

Did you declare 'temp_ad' as an int16 ? You need to do that.

If that's not the problem, then you should post a test program.
Copy and paste it in, from MPLAB. In other words, post a program
similar to what you posted above, but not code fragments. It should
be complete.

[bill conley]

Not int16 but long int, I think that's the same?



//read internal A/D on channel 0, (voltage input into controller)
void check_vin()
{
long int temp_ad = 0;
byte i;

/*
set_adc_channel(_3VDC_REF);
delay_us(100);
_3vdc_ = read_ADC(); //
delay_us(200);

set_adc_channel(_5VDC_);
delay_us(100);
_dvdc_ = read_ADC(); //
delay_us(200);

set_adc_channel(_5VDC_REF);
delay_us(100);
_5vref_ = read_ADC(); //
delay_us(200);

set_adc_channel(_48VDC_PWS_MAIN);
delay_us(100);
main_pws_input = read_ADC(); //
delay_us(200);

set_adc_channel(PPD_DETECT);
delay_us(100);
_vpos_ = read_ADC(); //
delay_us(200);


set_adc_channel(_12VDC_PWS_OPAMPS);
delay_us(100);
_12vdc_ = read_ADC(); //
delay_us(200);
*/

set_adc_channel(0);
delay_us(100);
temp_ad = Read_ADC(); //
delay_us(200);
//fprintf((COMM_PORT1),"+3Vdc: %lu\r",temp_ad);

set_adc_channel(1);
delay_us(100);
_dvdc_ = Read_ADC(); //
delay_us(200);

set_adc_channel(2);
delay_us(100);
_5vref_ = read_ADC(); //
delay_us(200);

set_adc_channel(3);
delay_us(100);
main_pws_input = read_ADC(); //
delay_us(200);

set_adc_channel(4);
delay_us(100);
_vpos_ = read_ADC(); //
delay_us(200);


set_adc_channel(5);
delay_us(100);
_12vdc_ = read_ADC(); //
delay_us(200);


//for(i=0;i < 10 ;i++)
//{
// temp_ad +=Read_ADC();
//}
//_3vdc_ = ( (long int)(temp_ad/10)); //
}



main()
{
byte l_hr,l_min,l_sec,l_day,l_mo,l_yr;
byte remote_page_num = 0;
byte i;
long int long_i;

long int ad_1 = 0;
long int ad_2 = 0;
long int ad_3 = 0;
long int ad_4 = 0;
float num_1 = 0;
float num_2 = 0;
float num_3 = 0;
float num_4 = 0;


char Received; //Added for 2nd UART
char Received2;
int rxflag=0;

//EEPROM_ADDRESS address;
//init_ext_eeprom(); //init e2rom
enable_interrupts(int_rda);
enable_interrupts(INT_RDA2);

int_count=INTS_PER_SECOND;
set_rtcc(0);
setup_counters (RTCC_INTERNAL, (RTCC_DIV_256 | RTCC_8_BIT));
setup_wdt(wdt_off);
enable_interrupts (INT_RTCC);
enable_interrupts(GLOBAL);

disable_interrupts (int_ext);

enable_interrupts (int_ccp3);
setup_ccp3(CCP_CAPTURE_RE); // Configure CCP2 to capture fall

enable_interrupts (int_ccp5);
setup_ccp5(CCP_CAPTURE_RE); // Configure CCP2 to capture fall

setup_psp(psp_disabled);
setup_adc_ports(ALL_ANALOG);
setup_adc (ADC_CLOCK_INTERNAL);


//setup_adc_ports( ALL_ANALOG );
port_b_pullups(TRUE);


set_tris_c(0xBF); // Set pin C6 as an output
set_tris_g(0xFD); // Set pin G1 as an output


do
{
check_vin();
} while(TRUE);

[PCM programmer]

Your test program is too complicated. Try this simple program
and see if it works.

[Ttelmah]

You have a huge amount of stuff in your code, that has been remarked out. Remove this, and repost, _showing the declarations of the variables used to hold the ADC valuea_. Also use the 'code' buttons to post.
Also, consider using an array, or struture to allow the whole thing to be done with one loop. Something like:

[bill conley]

Thanks Guys...I think I have it working. It wasn't the firmware, it was the hardware.

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