' =========================================================================
'
'   File....... Manual_DTMF.BS2
'   Purpose....
'   Author..... Jon Williams -- Parallax, Inc.
'   E-mail..... jwilliams@parallax.com
'   Started....
'   Updated.... 15 MAR 2005
'
'   {$STAMP BS2}
'   {$PBASIC 2.5}
'
' =========================================================================


' -----[ Program Description ]---------------------------------------------
'
' Generates DTMF tones using FREQOUT, using data from CM8870 tech sheet.
'
'          1209   1336   1477   1633
'        +------+------+------+------+
'    697 |   1  |   2  |   3  |   A  |
'        +------+------+------+------+
'    770 |   5  |   6  |   7  |   B  |
'        +------+------+------+------+
'    852 |   7  |   8  |   9  |   C  |
'        +------+------+------+------+
'    941 |   0  |   .  |   #  |   D  |
'        +------+------+------+------+


' -----[ Revision History ]------------------------------------------------


' -----[ I/O Definitions ]-------------------------------------------------


' -----[ Constants ]-------------------------------------------------------

#SELECT $STAMP
  #CASE BS2, BS2E, BS2PE
    T1200       CON     813
    T2400       CON     396
    T4800       CON     188
    T9600       CON     84
    T19K2       CON     32
    TMidi       CON     12
    T38K4       CON     6
  #CASE BS2SX, BS2P
    T1200       CON     2063
    T2400       CON     1021
    T4800       CON     500
    T9600       CON     240
    T19K2       CON     110
    TMidi       CON     60
    T38K4       CON     45
#ENDSELECT

SevenBit        CON     $2000
Inverted        CON     $4000
Open            CON     $8000

Baud            CON     T9600


' -----[ Variables ]-------------------------------------------------------

idx             VAR     Nib
char            VAR     Byte
valid           VAR     Byte
offset          VAR     Nib
frHi            VAR     Word
frLo            VAR     Word


' -----[ EEPROM Data ]-----------------------------------------------------

DTMF_Lo          DATA    Word  697, Word  770, Word  852, Word  941
DTMF_Hi          DATA    Word 1209, Word 1336, Word 1477, Word 1633


' -----[ Initialization ]--------------------------------------------------

Reset:
  DEBUG CLS


' -----[ Program Code ]----------------------------------------------------

Main:
  FOR idx = 0 TO 15
    LOOKUP idx, ["0123456789ABCD.#"], char
    DEBUG char, "    "
    GOSUB Get_DTMF_Freqs
    IF (valid <= 15) THEN
      DEBUG DEC3 frLo, "    ", DEC4 frHi
    ENDIF
    DEBUG CR
  NEXT

  END


' -----[ Subroutines ]-----------------------------------------------------

' Pass digit to dial in 'char'
' -- valid values are: '0' to '9', 'A' - 'D', '.', '#'

Get_DTMF_Freqs:
  valid = $FF
  LOOKDOWN char, ["0123456789ABCD.#"], valid
  IF (valid <= 15) THEN
    LOOKUP valid, [3,0,0,0,1,1,1,2,2,2,0,1,2,3,3,3], offset
    READ DTMF_Lo + (offset * 2), Word frLo
    LOOKUP valid, [0,0,1,2,0,1,2,0,1,2,3,3,3,3,1,2], offset
    READ DTMF_Hi + (offset * 2), Word frHi
  ENDIF
  RETURN
 