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

Bean's right, you need to use an external clock source for serial.  You can use a 4 MHz resonator since your rate is so slow.  

On the receive side you may want to allow for upper- and lowercase letters in your command header; here's how we do it at EFX-TEK with our serial accessories:

[code]' Use: theByte = RX_BYTE { ConvertToUppercase }
' -- converts "a".."z" to "A".."Z" if "ConvertToUppercase" bit 0 is 1

FUNC RX_BYTE
  IF __PARAMCNT = 1 THEN			' option specified
    tmpB2 = __PARAM1				' yes, save it
  ELSE
    tmpB2 = 0					' no, set to default
  ENDIF
  IF BaudRate = BR2400 THEN
    SERIN Sio, BaudSlow, tmpB1       		' for Prop-1/BS1
  ELSE
    SERIN Sio, BaudFast, tmpB1             	' for Prop-2/BS2
  ENDIF
  IF tmpB2.0 = Uppercase THEN			' convert to uppercase?
    IF tmpB1 >= "a" THEN                   	' lowercase?
      IF tmpB1 <= "z" THEN
        tmpB1.5 = 0                       	' ...yes, make uppercase
      ENDIF    
    ENDIF
  ENDIF
  RETURN tmpB1
  ENDFUNC[/code]

If you're expecting a character to be a letter then the function above can convert it to uppercase by using this calle:

[code]char = RX_BYTE 1[/code]

In my programs I use a constant called "Uppercase" so my listing is more readable:

[code]char = RX_BYTE Uppercase[/code]

If a non-letter character is received it is not changed by the function.  Note, too, that the function above checks the baud rate jumper on our boards; you can remove this check for a fixed baud system.

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