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Desperately need help with 1-wire, or HDQ16

 
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ye



Joined: 11 May 2005
Posts: 57
Location: london

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Desperately need help with 1-wire, or HDQ16
PostPosted: Thu Dec 15, 2005 5:52 am     Reply with quote
Hi all,

I am using 18f8722

There are 2 chips using 1-wire protocol in the system i am designing. One is DS2433 and the other is gas gauge BQ2060.

I have written a presence check code which works well with DS2433 but not on BQ2060.

The following one is my simple presence check code:
Code:


void IsGasGaugePresent(void)
{

   Bit_Clear(TrisE,5);    

   HDQ16 = 0;
   delay_us(100);
//   delay_ms(1);
   
   Bit_Set(TrisE,5);   

   delay_us(5);         
   if(!HDQ16)            
   {
      delay_us(500);
      printf("\nLine failed to be pulled high\n");
      while(1);
   }
   
   delay_us(60);    //was 110uS, but now aim to sample at 70uS post reset pulse
   present=(!HDQ16);   

   delay_us(300);   // Allow time for the PRESENCE PULSE to go

   if(present)    
   {
      printf("\nFound the device after %d tries\n", k);
      while(1);
   }

}



TI claims the 1-wire protocol on BQ2060 with a new name HDQ16. Since the same code works on one chip but not on another, my questions are:

1. is HDQ16 exactly following the timing of standard 1-wire protocol? If no, it could probably explain my case. However, it will be weird if the answer is no.

2. People may have realised I have a delay of 100us after HDQ16 = 0. It actually works and finds a logic-low pulse coming from HDQ16. However, it only found the gas gauge after being called 9 timers consecutively in a while(1) loop. Also the biggest point is, according to 1-wire protocol, the delay after 'HDQ16 = 0' is minimum 420us !

Can anybody help me with this strange timing??
ye



Joined: 11 May 2005
Posts: 57
Location: london

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PostPosted: Thu Dec 15, 2005 7:56 am     Reply with quote
nobody has experience in this? Shocked
ye



Joined: 11 May 2005
Posts: 57
Location: london

View user's profile Send private message

PostPosted: Thu Dec 15, 2005 9:27 am     Reply with quote
The 1-wire protocol timing given by these 3 documents or work are so different !!

somebody's code:
http://www.ccsinfo.com/forum/viewtopic.php?t=19520

1-wire protocol given by Dallas
http://www.maxim-ic.com/appnotes.cfm/appnote_number/126

1-wire protocol given by TI named as HDQ16
http://focus.ti.com/lit/ds/symlink/bq2060.pdf
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