osd-contiki/platform/osd-merkur/dev/t4-servo.c
2014-04-15 07:27:28 +02:00

151 lines
4.2 KiB
C
Raw Blame History

/*
** Copyright (C) 2013 Marcus Priesch, All rights reserved
** In Prandnern 31, A--2122 Riedenthal, Austria. office@priesch.co.at
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
** 1. Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in the
** documentation and/or other materials provided with the distribution.
** 3. Neither the name of the Institute nor the names of its contributors
** may be used to endorse or promote products derived from this software
** without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
** ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
** SUCH DAMAGE.
**
**++
** Name
** t4-servo
**
** Purpose
** Implements software pwm on any portpins via timer 4
**
**
** Revision Dates
** 31-Mar-2013 (MPR) Creation
** <20><>revision-date<74><65><EFBFBD><EFBFBD><EFBFBD>
**--
*/
#include "t4-servo.h"
#include <avr/io.h>
#include <avr/interrupt.h>
#include "led.h"
static servo_channel_type servo_channels [SERVO_COUNT];
// timer 4: CTC OCR4A
#define WGM4 0x4
void t4_servo_init (void)
{
unsigned char channel;
for (channel = 0; channel < SERVO_COUNT; channel ++)
{
servo_channels [channel].duty = SERVO_MAX/2;
t4_servo_set_io (channel, DEFAULT_PORT, DEFAULT_DDR, DEFAULT_PIN);
}
cli ();
TCCR4A = 0x00;
TCCR4A_struct.wgm4 = WGM4 & 0x3;
TCCR4B_struct.wgm4 = (WGM4 & 0xc) >> 2;
TCCR4B_struct.cs4 = 0x1; // No prescaler
TCCR4C = 0x00;
OCR4A = T4_VALUE;
TIMSK4_struct.ocie4a = 1;
sei();
}
void t4_servo_off (void)
{
TIMSK4_struct.ocie4a = 0;
}
int t4_servo_set_io
( unsigned char channel
, unsigned char port
, unsigned char ddr
, unsigned char pin
)
{
if (channel >= SERVO_COUNT)
return -1;
servo_channels [channel].port = port;
servo_channels [channel].ddr = ddr;
servo_channels [channel].pin = 1 << pin;
_SFR_IO8 (ddr) |= pin;
return 0;
}
int t4_servo_get (unsigned int channel)
{
if (channel >= SERVO_COUNT)
return -1;
return servo_channels [channel].duty;
}
int t4_servo_set (unsigned int channel, unsigned int duty)
{
if (channel >= SERVO_COUNT)
return -1;
if (duty > SERVO_MAX)
return -2;
if (duty < SERVO_MIN)
return -3;
servo_channels [channel].duty = duty;
return 0;
}
ISR (TIMER4_COMPA_vect, ISR_NOBLOCK)
{
unsigned char channel;
static unsigned int tick_count = 0;
cli ();
for (channel = 0; channel < SERVO_COUNT; channel ++)
{
if (tick_count < servo_channels [channel].duty)
{
// turn on
_SFR_IO8 (servo_channels [channel].ddr ) |= servo_channels [channel].pin;
_SFR_IO8 (servo_channels [channel].port) |= servo_channels [channel].pin;
}
else
{
// turn off
_SFR_IO8 (servo_channels [channel].port) &= ~(servo_channels [channel].pin);
_SFR_IO8 (servo_channels [channel].ddr ) |= servo_channels [channel].pin;
}
}
tick_count ++;
if (tick_count >= (SERVO_MAX + SERVO_OFFSET))
{
tick_count = 0;
}
sei();
}