' Name        : HSERXU.pbp
' Compiler    : PICBASIC PRO Compiler 2.6
' Assembler   : MPASM
' Target PIC  : PIC18F4550 or similar type
' Hardware    : LAB-XUSB Experimenter Board
' Oscillator  : 20MHz external
' Keywords    : DCD, HSERIN, HSEROUT, LCDOUT, NCD
' Description : PICBASIC PRO program to send and receive from
' the hardware serial port.
'

' Define LOADER_USED to allow use of the boot loader.
' This will not affect normal program operation.
Define LOADER_USED 1

' RESET_ORG can be set to move the BASIC program out of the way
' of any boot loader running from location 0, such as the
' Microchip USB boot loader
'Define RESET_ORG 800h

Define OSC 48      ' Core is running at 48MHz

' Define LCD pins
Define LCD_DREG  PORTD
Define LCD_DBIT  4
Define LCD_RSREG PORTE
Define LCD_RSBIT 0
Define LCD_EREG  PORTE
Define LCD_EBIT  1

char    Var Byte        ' Storage for serial character
col     Var Byte        ' Keypad column
row     Var Byte        ' Keypad row
key     Var Byte        ' Key value
lastkey Var Byte        ' Last key storage

   BAUDCON.3 = 1        ' Set for 16-bit baud rate generator
   SPBRG = 1249         ' Set for 2400 baud
   SPBRGH = 1249 / 256
   INTCON2.7 = 0        ' Enable PORTB pullups
   ADCON1 = 15          ' Set PORTA and PORTE to digital
   Low PORTE.2          ' LCD R/W line low (W)
   Pause 500            ' Wait for LCD to startup

   key = 0              ' Initialize vars
   lastkey = 0
   Lcdout $fe, 1        ' Initialize and clear display

mainloop:
   Hserin 1, tlabel, [char]' Get a char from serial port
   Lcdout char             ' Send char to display

tlabel:
   Gosub getkey            ' Get a keypress if any
   If (key != 0) and (key != lastkey) Then
      Hserout [key]        ' Send key out serial port
   Endif
   lastkey = key           ' Save last key value
   Goto mainloop           ' Do it all over again

' Subroutine to get a key from keypad
getkey:
   key = 0                 ' Preset to no key
   For col = 0 to 3        ' 4 columns in keypad
       PORTB = 0           ' All output pins low
       TRISB = (dcd col) ^ $ff ' Set one column pin to output
       Pauseus 1
       row = PORTB >> 4    ' Read row
       If row != $f Then gotkey ' If any keydown, exit
   Next col
   Return                  ' No key pressed

gotkey: ' Change row and column to ASCII key number
   key = (col * 4) + (ncd (row ^ $f)) + "0"
   Return                  ' Subroutine over

   End