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

Peter,

I am not sure if this is what you requseted. As much as I can understand of this, I think Jon's code is really pretty good; I kind of like his coding style. The first snippet is basically an SX/B version of getting the code from the irpin. The second snippet is the asm version. Both of these work, so, that is what I used to eliminate a board problem.

Some where along the line I will have to sit down and study this code, and see what it really means. 

Thanks

Ray

******CODE

This is a snippet of the SX/B SIRCS_ISR program non-asm version, in here lies the pulsin command, somewhere. 

                          
'_________________________________________________________________________
INTERRUPT NOPRESERVE
'_________________________________________________________________________

ISR_Start:
   if hasCmd = 1 then ISR_Exit
   if rxCmd = 1 then Check_Bit
   if irpin = 1 then ISR_Exit        

Start_Packet:
   rxCmd = 1
   rxBit = 1
   cmdWork = 0
   bitWidth = 0
   bitCount = 0
   goto ISR_Exit

Check_Bit:
   if irpin = 0 then Update_BitWidth
   if rxBit = 0 then ISR_Exit
   rxBit = 0
   if bitCount > 0 then Test_DBit

Test_SBit:
   if bitwidth > 74 then Next_Bit
   rxCmd = 0
   goto ISR_Exit

Test_DBit:
   cmdWork = cmdWork >> 1
   if bitWidth < 34 then Next_Bit
   cmdWork.6 = 1

Next_Bit:
   bitwidth = 0
   inc bitCount
   if bitCount < 8 then ISR_Exit
   hasCmd = 1
   cmdCode = cmdWork
   rxCmd = 0
   goto ISR_Exit

Update_Bitwidth:
   inc bitWidth
   rxBit = 1

ISR_Exit:
  returnint 104

*******************

This is a snippet of the asm version of the SIRCS_ISR program, in here lies the pulsin command also. This is a cut from Jon's original code. The variables apply to both snippets.


' -------------------------------------------------------------------------
' Variables
' -------------------------------------------------------------------------

cmdCode  VAR Byte   ' IR command code (7 bits)
cmdWork  VAR Byte   ' work space for cmd byte
bitCount VAR Byte   ' track bits received
bitWidth VAR Byte   ' measure bit width
flags  VAR Byte
rxCmd  VAR flags.0   ' receiving command
rxBit  VAR flags.1   ' measuring bit width?
hasCmd  VAR flags.2   ' command code available

temp1  VAR Byte   ' subroutine work vars
temp2  VAR Byte
temp3  VAR Byte


' -------------------------------------------------------------------------
  INTERRUPT NOPRESERVE
' -------------------------------------------------------------------------

ISR_Start:
  ASM
    JB    hasCmd, ISR_Exit   ' exit if holding command
    JB    rxCmd, Check_Bit   ' receiving now?
    JB    IR, ISR_Exit    ' exit if IR line idle

Start_Packet: 
    SETB  rxCmd     ' set rx flags
    SETB  rxBit
    CLR   cmdWork    ' clear work vars
    CLR   bitWidth
    CLR   bitCount
    JMP   ISR_Exit

Check_Bit: 
    JNB   IR, Update_BitWidth   ' still in bit?
    JNB   rxBit, ISR_Exit   ' in idle period?
    CLRB  rxBit     ' no, clear bit flag
    CJA   bitCount, #0, Test_DBit  ' start or data bit?

Test_SBit: 
    CJA   bitWidth, #74, Next_Bit  ' proper start bit?
    CLR   rxCmd     ' no, reset
    JMP   ISR_Exit

Test_DBit: 
    CLC
    RR    cmdWork    ' prep for next bit
    CJB   bitWidth, #34, Next_Bit  ' "1" bit?
    SETB  cmdWork.6    ' yes, set it

Next_Bit: 
    CLR   bitWidth    ' clear for next bit
    INC   bitCount    ' update count
    CJB   bitCount, #8, ISR_Exit  ' done?
    SETB  hasCmd    ' set available flag
    MOV   cmdCode, cmdWork   ' copy work to output
    CLRB  rxCmd     ' clear rx flag
    JMP   ISR_Exit

Update_BitWidth: 
    INC   bitWidth    ' else inc width
    SETB  rxBit     ' refresh in bit flag
  ENDASM

ISR_Exit:
  RETURNINT 104     ' 26 uS @ 4 MHz

---------- End of Message ----------


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