ADE7753

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markdem

Joined: 16 May 2006
Posts: 33

15 Mar 2008 7:12 ade7753 reset

Hi All, I am tring to write a driver for a ADE7753, but having some MAJOR problems. When I do a read to register 0x3f, which should be chip revision, I only get zero. Reads from any other register is the same. I have checked my hardware about 100 times, but it all seems to be OK. I dont have a scope to check the OSC or the SPI clock.

I have serached on this forum, the CCS forum and google, but I cant seem to find any code.

Has anybody actualy used this chip, and if so, could you PLAESE post the driver code.

Thank you

Mark

FvM

Joined: 22 Jan 2008
Posts: 5154
Helped: 766
Location: Bochum, Germany

15 Mar 2008 11:23 ade7753 code

The interface is similar to most Analog chips with an SPI interface. You most likely misunderstood the protocol or implemented it incorrect. I suggest to single step the code and to check the sequence of all SPI related signals during a communication cycle starting with /CS falling edge. Did you notice, that /RESET input also resets the interface? Holding /RESET low could probably also cause the said behaviour.

markdem

Joined: 16 May 2006
Posts: 33

22 Mar 2008 6:37 ade7753 software driver

Hello again, got some spare time today, so i Built a Proteus model so I can use the logic analyser, as i dont have a real one. After finding some small problems, I have made the PIC send out what the ADE7753 is expecting, including the CS and CLK lines. I have also simulated the ADE7753 response, and it all looks good. However, when I try this in real hardware, it still does not work. The responce from the ADE is always 255.

The following is my code,

Code:

#include <18F4550.h>

#fuses HSPLL,NOWDT,NOPROTECT,NOLVP,NODEBUG,USBDIV,PLL5,CPUDIV1,VREGEN,NOBROWNOUT,NOMCLR
#use delay(clock=48000000)

#define AD7758_CS    PIN_A0
#define ADE_DOUT    PIN_C7
#define ADE_DIN    PIN_B0
#define ADE_CLK    PIN_B1

#include "LCD420.c"

int test = 0, i, count;
int ADE_OUT_DATA = 63; //chip version register from datasheet

void main()
{
   lcd_init();
   printf(lcd_putc,"Ready");
   output_high(AD7758_CS);

   delay_ms(1000);

   while(1)
      {
         ADE_OUT_DATA = 63;
         output_low(AD7758_CS);
         delay_us(1);

         for(i=1;i<=8;++i)
            {
               output_high(ADE_CLK);
               delay_us(1);
               output_bit(ADE_DOUT, shift_left(&ADE_OUT_DATA,1,0));
               delay_us(1);
               output_low(ADE_CLK);
               delay_us(1);
            }

         output_low(ADE_DOUT);
         delay_us(4);

         for(i=1;i<=8;++i)
            {
               output_high(ADE_CLK);
               delay_us(1);
               shift_left(&test,1,input(ADE_DIN));
               output_low(ADE_CLK);
               delay_us(1);
            }

         output_high(AD7758_CS);

         lcd_gotoxy(1,1);                   //data returned from ADE7753
         printf(lcd_putc,"Data = %U",test);

         lcd_gotoxy(1,2);                   //Counter to show PIC is working
         printf(lcd_putc,"%U",count);

         delay_ms(500);

         count++;

      }
}

Can anyone see any problems that I have missed??

Thanks

Mark

Added after 1 hours 15 minutes:

One other thing I have just noticed, If I remove the ADE7753, is still get 255 as the return. I dont have to pull the SPI Lines down, do I?

Thanks again,

Mark

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FvM

Joined: 22 Jan 2008
Posts: 5154
Helped: 766
Location: Bochum, Germany

22 Mar 2008 12:02 ade7753 proteus

I think, the read operation is correct so far. This means, you most likely have a hardware problem (unconnects, shorts, mixed up signals). I repeat my suggestion to single step the code and check the signals at ADE7753 for each bit cycle. With ADE removed, you get the response from floating ADE_DIN. It should be 0 when pulling it down.

BTW.: You named your input signal ADE_DIN. But this line must be connected to ADE DOUT pin!