How to configure Adc of pic18f4553

[hayawana]

Hi everyone,

I'm working on PIC18F4553 on Digital Analog Converter(12-bit converter), and I use a 20MHz crystal.

The result is contained in two registers ADRESH and ADRESL.I have read the datasheet but I still do not see how to display the result on the output pin of the µC.
I use mikroC, I send you attached the wiring diagram in proteus. I need some help with that

Here initialization:
/ / / / / / / / / Initialization / / / / / / / / / / / / / / / / / /
ADCON0 = 0x00, / / select channel AN0 using ADCON0 register
ADCON1 = 0x03 / / VSS, VDD, select AN0 as analog and digital as AN12
ADCON2 0xAD = / / Right Justified, 12TAD, 16TOSC
TRISA = 0xFF; / / set as inputs TRISA
TRISB = 0x00, / / set TRISB as ouputs
ADON_bit = 1 / / enable conversion

Thank you,

 

[snishanth512]

I'm working on PIC18F4553 on Digital Analog Converter(12-bit converter), and I use a 20MHz crystal.

Thank you,

ADC or DAC ?????

 

[hayawana]

oh my bad i thought i could use the RB0 pin as an analog output this is my first mistake. but still dont know how to conversion.

- - - Updated - - -

oh my bad i thought i could use the RB0 pin as an analog output this is my first mistake. but still dont know how to conversion.

 

[xpress_embedo]

Have a look at this link:-

https://sites.google.com/site/coole...0/tutorial-list/temperature-monitoring-system

 

[hayawana]

Hi,

thank youu but i dont want to display the result . I want to transfer it through USB and UART. I have 6 channels to convert then transfer. Any ideas please?

 

[jayanth.devarayanadurga]

See the project I have done here.

https://www.edaboard.com/threads/271037/

https://www.edaboard.com/threads/271146/#post1161576

 

[hayawana]

thank you.

ANY IDEAS about converting 6 channels using interruptions?

 

[jayanth.devarayanadurga]

You mean 6 Channel ADC using ADC interrupts? Only one channel is read at a time. You can use ADC interrupts. When ADC Conversion is complete ADIF bit is set.

 

[hayawana]

YES so he will read the first one when he finishes and send the adif flag he could start the other one?

 

[jayanth.devarayanadurga]

When one conversion is completed which you check by if ADIF is set or not then save the result to a variable and then start second conversion and repeat for all the adc inputs you want to convert.

 

[hayawana]

thank you . i also need to know how can i do to transfer the result 12 bits to UART 8 bits ?

 

[Golden Electronics]

Split data into 8 bit & transfer LSB then msb or vice versa

 

[hayawana]

Hello, thank you very much for your answers

But I'm really bad programming and I just started and I'm lost. But I still do not see how to convert at least two signals and transfer them to 12 bits, while the uart supports 8-bit, I put a small piece of code that may seem stupid to some:

void main()
{
/////////Initialisation//////////////////
ADCON0=0x00; //select AN0 canal using register ADCON0
ADCON1=0x00; //VSS,VDD, select AN0
ADCON2=0xAD; //Right justified, 12TAD, 16TOSC
TRISA=0x01; // set trisA as inputs
TRISD=0x00; // set trisD as ouputs
TRISC=0x00; // set trisD as ouputs
ADIF_bit=0;
ADON_bit=1; // enable conversion
while(1)
{
conversion1 = ADC_Read(0); // Read analog value from channel 0
//conversion =0x0FA5;
PORTD= (char) conversion1;
Delay_Cyc(10);
/*ADIF_bit =1; // set flag adif
ADCON0=0x01; //select AN1 canal using register ADCON0
conversion2 = ADC_Read(1); // Read analog value from channel 0
//conversion =0x0FA5;
PORTC= (char) conversion2;*/

 

[Golden Electronics]

if conversion - 0x0FA5;
then
lsb = (unsigned char) (conversion & 0x00FF);
msb = (unsigned char) ((conversion>>8) & 0x00FF);

 

[jayanth.devarayanadurga]

If conversion1 is a int variable (16 bits wide) then add two char type variables lowbyte and highbyte.

lowbyte = conversion1; //puts the low byte of conversion1 into lowbyte
highbyte = conversion >> 8; //puts the high byte of conversion1 into highbyte

PORTC = lowbyte
PORTD = highbyte

UART1_Write(lowbyte);
UART1_Write(highbyte);

 

[hayawana]

Thank you very much guys its very helpful. :-D
But can you show me an example of the conversion of 3 canals? how can i convert the first one then say ok its done convert the second one and so on?

 

[hayawana]

no one here?