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adc2543 pic18f4520 SPI communication

 
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kazanova64



Joined: 10 Apr 2010
Posts: 8

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adc2543 pic18f4520 SPI communication
PostPosted: Sun Apr 11, 2010 6:36 am     Reply with quote
Hi everybody, I am new to embedded system design and need help. Using 18F4520, I want to read adc output and put it on the lcd but I could not do it. I want to use ADC2543 with 8 bits CS enable mode.
Code:

#include "C:\Documents and Settings\ozora\Belgelerim\Workspace\PIC\ccs-pcw\Yeni Klasör\main.h"
#use delay(clock=16000000)

#use spi(DI=PIN_B1, DO=PIN_B0, CLK=PIN_B2, ENABLE=PIN_B4, BITS=8 )

#define LCD_ENABLE_PIN PIN_D0
#define LCD_RS_PIN PIN_D1
#define LCD_RW_PIN PIN_D2
#define LCD_TYPE 2
#define SPI_MODE_0 (SPI_L_TO_H | SPI_XMIT_L_TO_H)

int8 value=0;
char mystring[15];
int8 i;

#define io_clk                PIN_B2
#define ad_adress_in          PIN_B0
#define ad_data_out           PIN_B1
#define ad_cs                 PIN_B3

int8 ADC_get(void)
{ 
   output_low(ad_cs);
   delay_ms(10);
   value=spi_read(0x04);
   delay_ms(10);
   output_high(ad_cs);
   delay_ms(100);
   return(value);
}

void ADC_init(void)
{
   output_low(io_clk);
   output_high(ad_cs);
   ADC_get();
}   

#include <lcd.c>

void main()
{ 
   setup_adc_ports(NO_ANALOGS|VSS_VDD);
   setup_adc(ADC_OFF|ADC_TAD_MUL_0);
   setup_psp(PSP_DISABLED);
   setup_spi(SPI_MASTER|SPI_L_TO_H|SPI_CLK_DIV_64);
   setup_wdt(WDT_OFF);
   setup_timer_0(RTCC_INTERNAL);
   setup_timer_1(T1_DISABLED);
   setup_timer_2(T2_DISABLED,0,1);
   setup_timer_3(T3_DISABLED|T3_DIV_BY_1);
   setup_comparator(NC_NC_NC_NC);
   setup_vref(FALSE);

   lcd_init();
   adc_init();
   
   while(1) {
      value=ADC_get();
      sprintf(mystring,"<%d>",value);
      lcd_putc("\f");
      for(i=0;i<=14;i++){
         lcd_putc(mystring[i]);
      }
      delay_ms(100);

//Setup_Oscillator parameter not selected from Intr Oscillotar Config tab

   // TODO: USER CODE!!
}
}

I execute the process with Proteus. SPI outputs can not be generated from PIC. Can you help me?
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Sun Apr 11, 2010 4:49 pm     Reply with quote
You have some problems in your code.

Quote:

#use spi(DI=PIN_B1, DO=PIN_B0, CLK=PIN_B2, ENABLE=PIN_B4, BITS=8 )

In the code above, you specify a software SPI port on Port B.

Quote:

setup_spi(SPI_MASTER|SPI_L_TO_H|SPI_CLK_DIV_64);

value=spi_read(0x04);

But then in your program shown above, you use the hardware SPI
functions setup_spi() and spi_read() which are on pins C3, C4, and C5.
Delete the #use spi() statement. You are not using it.


Quote:

setup_spi(SPI_MASTER|SPI_L_TO_H|SPI_CLK_DIV_64);

Another thing. The TLC2543 data sheet shows that SPI mode 0 is used,
but in the code above, you have specified SPI mode 1. That's wrong.
Look at Figure 13 on page 11 of the data sheet:
http://focus.ti.com/lit/ds/symlink/tlc2543.pdf
It shows that I/O Clock (SCLK) idles at a low level, and samples data
on the rising edge. According to this diagram, that's SPI mode 0:
http://www.totalphase.com/support/kb/10045/#modes
Here are the SPI modes #defines for 16F and 18F PICs:
Code:

#define SPI_MODE_0  (SPI_L_TO_H | SPI_XMIT_L_TO_H)
#define SPI_MODE_1  (SPI_L_TO_H)
#define SPI_MODE_2  (SPI_H_TO_L)
#define SPI_MODE_3  (SPI_H_TO_L | SPI_XMIT_L_TO_H)
kazanova64



Joined: 10 Apr 2010
Posts: 8

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PostPosted: Mon Apr 12, 2010 12:06 pm     Reply with quote
Thanks for your reply. I had not known that spi pins are in portc.

Code:

#include "C:\Documents and Settings\ozora\Belgelerim\Workspace\PIC\ccs-pcw\Yeni Klasör\main.h"
#use delay(clock=16000000)
#define LCD_ENABLE_PIN PIN_D0
#define LCD_RS_PIN PIN_D1
#define LCD_RW_PIN PIN_D2
#define LCD_TYPE 2
#define SPI_MODE_0  (SPI_L_TO_H | SPI_XMIT_L_TO_H)
#define SPI_MODE_1  (SPI_L_TO_H)
#define SPI_MODE_2  (SPI_H_TO_L)
#define SPI_MODE_3  (SPI_H_TO_L | SPI_XMIT_L_TO_H)

unsigned int8 value=0;
char mystring[15];
int8 i;

#define ad_cs                 PIN_B3

int8 ADC_get(void)
{ 
   output_low(ad_cs);
   delay_ms(10);
   value=spi_read(0x04);
   delay_ms(100);
   output_high(ad_cs);
   return(value);
}

void ADC_init(void)
{
   output_high(ad_cs);
   ADC_get();
}   

#include <lcd.c>
void main()
{ 
   setup_adc_ports(NO_ANALOGS|VSS_VDD);
   setup_adc(ADC_OFF|ADC_TAD_MUL_0);
   setup_psp(PSP_DISABLED);
   setup_spi(SPI_MASTER|SPI_MODE_0|SPI_CLK_DIV_4);
   setup_wdt(WDT_OFF);
   setup_timer_0(RTCC_INTERNAL);
   setup_timer_1(T1_DISABLED);
   setup_timer_2(T2_DISABLED,0,1);
   setup_timer_3(T3_DISABLED|T3_DIV_BY_1);
   setup_comparator(NC_NC_NC_NC);
   setup_vref(FALSE);
   lcd_init();
   adc_init();
   
   while(1) {
      value=ADC_get();
      sprintf(mystring,"<%d>",value);
      lcd_putc("\f");
      for(i=0;i<=14;i++){
         lcd_putc(mystring[i]);
      }
      delay_ms(100);

//Setup_Oscillator parameter not selected from Intr Oscillotar Config tab

   // TODO: USER CODE!!
}
}
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Mon Apr 12, 2010 12:16 pm     Reply with quote
Is it now working ? You didn't say.
kazanova64



Joined: 10 Apr 2010
Posts: 8

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PostPosted: Tue Apr 13, 2010 12:53 am     Reply with quote
Yes, it is working. I simulated in proteus and the PIC can communicate with adc - lcd and gives the adc result to the lcd.
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