sdcc/device/lib/pic16/libio/usart/uputc.c

   1 /*-------------------------------------------------------------------------
   2    uputc - write a character to USART
   3
   4    Copyright (C) 2004, Vangelis Rokas <vrokas AT otenet.gr>
   5
   6    This library is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by the
   8    Free Software Foundation; either version 2, or (at your option) any
   9    later version.
  10
  11    This library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this library; see the file COPYING. If not, write to the
  18    Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  19    MA 02110-1301, USA.
  20
  21    As a special exception, if you link this library with other files,
  22    some of which are compiled with SDCC, to produce an executable,
  23    this library does not by itself cause the resulting executable to
  24    be covered by the GNU General Public License. This exception does
  25    not however invalidate any other reasons why the executable file
  26    might be covered by the GNU General Public License.
  27 -------------------------------------------------------------------------*/
  28
  29 /*
  30  * Devices implemented:
  31  *      PIC18F[24][45][28]
  32  */
  33
  34
  35 #include <pic18fregs.h>
  36 #include <usart.h>
  37
  38 extern union USART USART_Status;
  39
  40 void usart_putc(unsigned char dat) __wparam __naked
  41 {
  42 #if 0
  43   if(TXSTAbits.TX9) {
  44     TXSTAbits.TX9D = 0;
  45     if(USART_Status.TX_NINE)TXSTAbits.TX9D = 1;
  46   }
  47
  48   TXREG = dat;      // Write the data byte to the USART
  49 #else
  50   dat;
  51   __asm
  52     btfss       _TXSTAbits, 6
  53     bra         _01_
  54
  55     bcf         _TXSTAbits, 0
  56     banksel     _USART_Status
  57     btfsc       _USART_Status, 1, b
  58     bsf         _TXSTAbits, 0
  59
  60 _01_:
  61     movwf       _TXREG
  62     return
  63   __endasm;
  64 #endif
  65 }