'-----------------------------------------------------------------------------------------
'    Name:  REAL_TO_BAM_CONVERSION.TIG
'    Type:  TIGER-BASIC(tm) Source Code
'
' Purpose:  Converts a Tiger 64-bit REAL value into a 16-bit BAM value
'
'  (C) - Copyright Wilke Technology, P.O.Box 1727, D-52018 Aachen, Germany
'-----------------------------------------------------------------------------------------
'	
' Thank you for using BASIC Tigers in your products. If you have questions, ideas
' or special needs, please contact your next distributor or the Tiger support team
' and visit our web site:
'
'	Wilke Technology GmbH
'	The Tiger Support Team
'	P.O.Box 1727,       D-52018 Aachen, Germany
'	Krefelder Str. 147, D-52070 Aachen, Germany
'
'	email: support@wilke-technology.com  (english)
'	email: support@wilke.de              (german)
'	Phone: +49 (241) 918 900    Mo to Fr, 7:00 to 16:00 (GMT)
'	Fax:   +49 (241) 918 9068
'
' New information, new drivers and free downloads see:
'
'	www.wilke-technology.com	     (english)
'	www.wilke.de                         (german)
'
' Sincerely,
'
'	Your Tiger Support Team
'
'
'-----------------------------------------------------------------------------------------
'
' Example program for converting a Tiger 64-bit REAL value into a 16-bit BAM (Binary
' Angle Measurement) system value. Valid values for the BAM system are between 0 and 360.
'
' The program uses one global array holding the numerical values for each of the 16 BAM
' system bit, which is initialized calling the subroutine BAM_INIT.
'
' For the conversion itself, there is a subroutine REAL2BAM, which is called with
' 2 parameters:
'   Input:	RealValue	= REAL variable containing the value to be converted
'				  (can be any variable name, RealValue is just example)
'
'   Output:	BAMValue	= WORD variable containing the converted value in BAM format
'				  (can be any variable name, RealValue is just example)
'
'.........................................................................................
'
' In this example program the 16-bit BAM value is additionally outputted on
' Tiger ports 6 and 8 in the following order:
'
' Bit-No.:	 15| 14| 13| 12| 11| 10|  9|  8|  7|  6|  5|  4|  3|  2|  1|  0
' Tiger-Pin:	L87|L86|L85|L84|L83|L82|L81|L80|L67|L66|L65|L84|L83|L82|L81|L80
'
'-----------------------------------------------------------------------------------------
USER_VAR_STRICT

USER_EPORT 1,0				' disable EPort system (only for port 6 output)

ARRAY BAM_BITVALUE(16) OF REAL		' global array for BAM bit values


TASK MAIN				' begin task MAIN

  REAL RealValue			' REAL value to be converted
  WORD BAMValue				' 16-bit BAM value
  BYTE HiByte, LoByte			' Bytes for port output

  DIR_PORT 6, 0				' Port 6 is output (Low BYTE of BAM WORD)
  DIR_PORT 8, 0				' Port 8 is output (Hi BYTE of BAM WORD)

  CALL BAM_INIT				' initialize BAM bit value array

  RealValue = 137.10			' example value to be converted
'  RealValue = 180.0			' example value to be converted
'  RealValue = 360.0			' example value to be converted

  CALL Real2BAM (RealValue, BAMValue)	' call conversion REAL --> BAM

  HiByte = BAMValue SHR 8		' extract high byte from BAM value
  LoByte = BAMValue BITAND 255		' extract low byte from BAM value

  OUT 8, 255, HiByte			' output high byte on Tiger port 8
  OUT 6, 255, LoByte			' output low byte ob Tiger port 6

END					' end task MAIN


'-----------------------------------------------------------------------------------------
' Subroutine initializing the array with the BAM format bit values
'-----------------------------------------------------------------------------------------
SUB BAM_INIT				' begin subroutine for initialization

  BAM_BITVALUE(15) = 180.0		' Value for MSB (Bit 15)
  BAM_BITVALUE(14) = 90.0
  BAM_BITVALUE(13) = 45.0
  BAM_BITVALUE(12) = 22.5
  BAM_BITVALUE(11) = 11.25
  BAM_BITVALUE(10) = 5.625
  BAM_BITVALUE( 9) = 2.8125
  BAM_BITVALUE( 8) = 1.406
  BAM_BITVALUE( 7) = 0.703
  BAM_BITVALUE( 6) = 0.3515
  BAM_BITVALUE( 5) = 0.1757
  BAM_BITVALUE( 4) = 0.088
  BAM_BITVALUE( 3) = 0.0439
  BAM_BITVALUE( 2) = 0.0219
  BAM_BITVALUE( 1) = 0.0109
  BAM_BITVALUE( 0) = 0.0055		' Value for LSB (Bit 0)

END					' end subroutine for initialization


'-----------------------------------------------------------------------------------------
' Subroutine converting a real value to a BAM 16-bit WORD
'-----------------------------------------------------------------------------------------
SUB Real2BAM (REAL InValue; VAR WORD OutValue)	' begin subroutine for conversion

  REAL LocalReal				' holp variable, can be altered
  BYTE B					' counter for bit position

  OutValue = 0					' initialize output value
  LocalReal = InValue				' copy input value to help var

  IF LocalReal = 360.0 THEN			' Special case for BAM: all bits to 0 when
    LocalReal = 0.0				' angle value is either 0 or 360
  ENDIF						'
  FOR B = 15 TO 0 STEP -1			' loop over all 16 bits
    IF LocalReal >= BAM_BITVALUE(B) THEN	' if input value >= BAM bit value
      LocalReal = LocalReal - BAM_BITVALUE(B)	' subtract bit value from input value
      OutValue = OutValue + EXP(2, B)		' set bit in output value by adding 2^bit
    ENDIF					'
  NEXT						' next bit

END						' end subroutine for conversion