103 lines
2.5 KiB
C
103 lines
2.5 KiB
C
/**
|
|
* Copyright (C) 2009 Ubixum, Inc.
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
**/
|
|
|
|
|
|
#include <fx2regs.h>
|
|
#include <fx2macros.h>
|
|
#include <serial.h>
|
|
|
|
|
|
/**
|
|
* using the comp port implies that timer 2 will be used as
|
|
* a baud rate generator. (Don't use timer 2)
|
|
**/
|
|
void
|
|
sio0_init(WORD baud_rate)
|
|
__critical
|
|
{ // baud_rate max should be 57600 since int=2 bytes
|
|
|
|
WORD hl; // hl value for reload
|
|
BYTE mult; // multiplier for clock speed
|
|
DWORD tmp; // scratch for mult/divide
|
|
|
|
// 0 = 12mhz, 1=24mhz, 2=48mhz
|
|
mult = CPUFREQ == CLK_12M ? 1 : CPUFREQ == CLK_24M ? 2 : 4; // since only 3 clock speeds, fast switch instead of doing 2^clock speed pow(2,clkspd)
|
|
|
|
// set the clock rate
|
|
// use clock 2
|
|
RCLK = 1;
|
|
TCLK = 1;
|
|
|
|
// RCAP2H:L = 0xFFFF - CLKOUT / 32 x baud_rate
|
|
|
|
// in order to round to nearest value..
|
|
// tmp * 2 // double
|
|
// tmp / rate // do the divide
|
|
// tmp + 1 // add one (which is like adding 1/2)
|
|
// tmp / 2 // back to original rounded
|
|
tmp = mult * 375000L * 2;
|
|
tmp /= baud_rate;
|
|
tmp += 1;
|
|
tmp /= 2;
|
|
|
|
hl = 0xFFFF - (WORD) tmp;
|
|
|
|
RCAP2H = MSB(hl);
|
|
// seems that the 24/48mhz calculations are always one less than suggested values
|
|
// trm table 14-16
|
|
RCAP2L = LSB(hl) + (mult > 0 ? 1 : 0);
|
|
TR2 = 1; // start the timer
|
|
|
|
// set up the serial port
|
|
SM0 = 0;
|
|
SM1 = 1; // serial mode 1 (asyncronous)
|
|
SM2 = 0; // has to do with receiving
|
|
REN = 1; // to enable receiving
|
|
PCON |= 0x80; // SET SMOD0, baud rate doubler
|
|
TI = 1; // we send initial byte
|
|
|
|
}
|
|
|
|
char
|
|
getchar()
|
|
{
|
|
char c;
|
|
while (!RI);
|
|
c = SBUF0;
|
|
RI = 0;
|
|
return c;
|
|
}
|
|
|
|
void
|
|
_transchar(char c)
|
|
{
|
|
while (!TI); // wait for TI=1
|
|
TI = 0;
|
|
SBUF0 = c;
|
|
}
|
|
|
|
void
|
|
putchar(char c)
|
|
{
|
|
if (c == '\n')
|
|
_transchar('\r'); // transmit \r\n
|
|
_transchar(c);
|
|
if (c == '\r')
|
|
_transchar('\n'); // transmit \r\n
|
|
}
|