-- Copyright (C) 2002 Javier Martínez
--
-- This software is provided 'as-is', without any express or implied 
-- warranty. In no event will the authors be held liable for any damages 
-- arising from the use of this software.
--
-- Permission is granted to anyone to use this software for any purpose, 
-- including commercial applications, and to alter it and redistribute it 
-- freely, subject to the following restrictions:
--
-- 1. The origin of this software must not be misrepresented; 
--    you must not claim that you wrote the original software. 
--    If you use this software in a product, an acknowledgment in 
--    the product documentation would be appreciated but is not required.
--
-- 2. Altered source versions must be plainly marked as such, and must 
--    not be misrepresented as being the original software.
--
-- 3. This notice may not be removed or altered from any source distribution.
--
-- This license is commonly known as the zlib/libpng License.
--
-- 
-- --------------------------------------------------------------------
-- file      : f452_serial.jal
-- author    : Javier Martínez
-- date      : 20021113
-- purpose   : 18F452 Hardware serial module 
-- requires  : jpic16,jal
--
-- Copyright (C) 2002 Javier Martínez
--
-- See readme.txt

-- --------------------------------------------------------------------
-- Declarations
-- --------------------------------------------------------------------

include jpic16

-- --------------------------------------------------------------------
-- USER configuration area
-- --------------------------------------------------------------------

const BAUD_CONSTANT = 9600
-- const BAUD_CONSTANT = 57600


-- Select a baudrate from this table:

-- =================================
-- Fosc = 4MHz
-- _________________________________
-- Baud		%Err	SPBRG	BRGH
-- 
--   300	-0.17	0xCF	0
--  1200	0.17	0xCF	1
--  9600	0.16	0x19	1
-- 19200	0.16	0x0C	1
 
-- =================================
-- Fosc = 10MHz
-- _________________________________
-- Baud		%Err	SPBRG	BRGH
-- 
-- 1200		0.16	0x81	0
-- 9600		0.16	0x40	1
 
-- =================================
-- Fosc = 20MHz
-- _________________________________
-- Baud		%Err	SPBRG	BRGH
-- 
--  9600	0.16	0x81	1
-- 19200	0.16	0x40	1
 
-- =================================
-- Fosc = 40MHz
-- _________________________________
-- Baud		%Err	SPBRG	BRGH
-- 
--  9600	-0.16	0x40	0
-- 19200	-0.16	0x81	1
-- 38400	-0.16	0x40	1
-- 57600	-0.93	0x2A	1

-- --------------------------------------------------------------------
-- Body
-- --------------------------------------------------------------------




procedure f452_serial_setup is begin
     pin_c7_direction = input
     pin_c6_direction = output
     TXSTA = 0x00
  if ( ( target_clock == 4_000_000 ) &  ( BAUD_CONSTANT == 300 ) ) |
     ( ( target_clock == 10_000_000 ) &  ( BAUD_CONSTANT == 1_200 ) ) |
     ( ( target_clock == 40_000_000 ) &  ( BAUD_CONSTANT == 9_600 ) ) then
    SPBRG = ( target_clock / ( 64 * BAUD_CONSTANT ) ) - 1
    TXSTA_BRGH = low
  else
    SPBRG = ( target_clock / ( 16 * BAUD_CONSTANT ) ) - 1
    TXSTA_BRGH = high
  end if
  RCSTA = 0x00
  TXSTA_TXEN = High
  RCSTA_CREN = high
  RCSTA_SPEN = high
  asm movf RCREG , w  -- clear init buffer
  asm movf RCREG , w
end procedure


function getc'get return byte is
  while ! PIR1_RCIF loop end loop
  return RCREG
end function

procedure putc'put ( byte in data ) is begin
  while ! PIR1_TXIF loop end loop
  TXREG = data
end procedure