Calculating Baud Rate

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'RTTY with NTX2 Test written by paul swingewood
'March 2013   - PIC 16F628A
'Based on code developed by Rob Harrison for Arduino
'--------------------------------------------------------------------------

'Define SIMULATION_WAITMS_VALUE = 2


Define CONF_WORD = 0x3f50  'Internal Oscillator'
Define CLOCK_FREQUENCY = 4
AllDigital

'Define the comms for the LCD display.
Define LCD_LINES = 4
Define LCD_CHARS = 20
Define LCD_BITS = 4
Define LCD_DREG = PORTB
Define LCD_DBIT = 4  'Use the high order bits'
Define LCD_RSREG = PORTA
Define LCD_RSBIT = 2
Define LCD_EREG = PORTA
Define LCD_EBIT = 0
Define LCD_RWREG = PORTA
Define LCD_RWBIT = 1
Define LCD_READ_BUSY_FLAG = 1


Define LCD_COMMANDUS = 5000  'delay after LCDCMDOUT, default value is 5000
Define LCD_DATAUS = 100  'delay after LCDOUT, default value is 100
Define LCD_INITMS = 20


Define SEROUT_DELAYUS = 1000

Symbol txcr_pin = PORTA.7
Dim i As Byte  'used for loops
Dim j As Byte  'used for loops
Dim pos As Byte  'used for lcd position
Dim ch As Byte  'used to hold individual character
Dim times_sent As Byte  'used to check number of times sent before waiting
startup:
Lcdinit LcdCurBlink
Lcdcmdout LcdClear
WaitMs 100

times_sent = 0
loop:
Lcdcmdout LcdClear
For i = 0 To 15
ch = LookUp("RTTY TEST BEACON"), i
pos = i + 1
Call convert_char(ch)
Next i
If times_sent = 4 Then
	WaitMs 5000
	times_sent = 0
Endif
times_sent = times_sent + 1
Goto loop
End                                               

Function convert_char(chr As Byte) As Byte
Lcdcmdout LcdLine1Pos(pos)
Lcdout chr

Call rtty_txbit(0)  'start Bit

For j = 0 To 7  'ascii-7 / ascii-8
	'Lcdcmdout LcdLine3Pos(1)
	'Lcdout "Bit ", #j,
	If chr.0 Then
		'Lcdcmdout LcdLine3Pos(8)
		'Lcdout "= HIGH" ' -- Use the scope to see this is true!
		Call rtty_txbit(1)
	Else
		'Lcdcmdout LcdLine3Pos(8)
		'Lcdout "= LOW "
		Call rtty_txbit(0)
	Endif
chr = ShiftRight(chr, 1)
Next j

Call rtty_txbit(1)  'stop Bit
Call rtty_txbit(1)  'stop Bit

End Function                                      

Function rtty_txbit(b As Bit) As Bit

If b = 1 Then
'High
	High txcr_pin
Else
'Low
	Low txcr_pin
Endif

WaitUs 20000  '1/50th of a second = 50 Baud?
End Function