In SX Microcontrollers, SX/B Compiler and SX-Key Tool, johncouture wrote:

Jon, 

I'm stuck.  I'm not having any luck with porting your program so I figured I try and reduce a SearchROM routine to something where I can at least get something from the AAG WS.  So far I'm only getting zeroes, even right after the RESET which implies a short.  AAG WS is connected to GND and to RB.2 (DQ constant).  The DS2450 does show +5 for the HIGH DQ command (one second) and ground on the AAG WS seems to be good.

Main:
   tris_b=%00000000         ' Set pin direction 0=Output, 1=input
   HIGH DQ                  ' Charge the AAG capacitor (DQ is RB.2)
   wait_ms 250,4            '   for one second
   MyCount = 0              ' Initialize all my counters
   Result = 0
   ROMidx = 0
   NextBit = 0

 

Main2:
   LCDPos 20                ' using 4x20 LCD, position cur at beg of line 2
   TX_Out "              "  ' clear the line with spaces
   LCDPos 20                ' position again at beginning of line
   TX_HEX2 MyCount          ' display # of tries
   TX_Out "-"               ' display a dash
   OWRESET DQ,Result        ' Reset bus and read result
   Result = Result + $30    ' Convert Result into ASCII
   TX_OUT Result            ' Display Result on LCD
   OWWRByte DQ,SearchROM    ' Now send command to search
   Result = 0               ' Clear 

 

ReadBit:
   OWRDBit DQ,Result.1      ' Read a bit
   OWRDBit DQ,Result.0      ' Read another bit
   Result = Result + $30    ' Convert Result into ASCII
   TX_Out Result            ' Display Result on LCD
   Result = 0               ' Clear Result for next read

 

WriteNextBit:
   inc ROMidx               ' increment the bit position I'm using
   OWWRBit DQ,NextBit.0     ' write a zero (eventually this will flip-flop)
   if ROMidx < 64 then ReadBit ' later this will be changed to 64 bits

 

PackupAndStartAgain:             
   wait_ms 250,10           ' wait about 2.5 seconds
   ROMidx = 0               ' try again
   inc MyCount 
   goto Main2

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