96 lines
3.2 KiB
C
96 lines
3.2 KiB
C
/*
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** Copyright (C) 2013 Marcus Priesch, All rights reserved
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** In Prandnern 31, A--2122 Riedenthal, Austria. office@priesch.co.at
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**
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** Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions
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** are met:
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** 1. Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** 2. Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in the
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** documentation and/or other materials provided with the distribution.
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** 3. Neither the name of the Institute nor the names of its contributors
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** may be used to endorse or promote products derived from this software
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** without specific prior written permission.
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**
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** THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
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** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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** ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
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** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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** SUCH DAMAGE.
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**
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**++
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** Name
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** t4-servo
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**
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** Purpose
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** Implements software pwm on any portpins via timer 4
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**
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**
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** Revision Dates
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** 31-Mar-2013 (MPR) Creation
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** <20><>revision-date<74><65><EFBFBD><EFBFBD><EFBFBD>
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**--
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*/
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#ifndef __T4_SERVO_H__
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#define __T4_SERVO_H__
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// timing: (X:pwm, _:zero)
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//
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// X_______________XXXXXXXXXXXXX_______________XXXXXXXXXXXXX
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//
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// |<------------->|<--------->|<------------->|<--------->| ...
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// SERVO_OFFSET SERVO_MAX SERVO_OFFSET SERVO_MAX
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//
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// within SERVO_MAX you get the PWM set with servo_set (id, pwm)
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// if you set SERVO_OFFSET to zero, you get a pwm from 0 to 100% duty cycle
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//
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// the period of the smallest tick is derived from the timer4 prescaler
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// plus the ISR overhead. however, the latter one should be constant
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// regardless of the pwm signal generated
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#define SERVO_OFFSET 256
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#define SERVO_MIN 16
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#define SERVO_MAX 32
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// Counter value for timer 4 without any prescaler for a single tick
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#define PWMFREQ 500
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#define T4_VALUE F_CPU/SERVO_MAX/PWMFREQ
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#define SERVO_COUNT 4
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#define DEFAULT_PORT 0x0E
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#define DEFAULT_PIN 1
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#define DEFAULT_DDR 0x0D
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typedef struct struct_servo_channel
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{
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unsigned char port;
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unsigned char pin;
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unsigned char ddr;
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unsigned char duty;
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} servo_channel_type;
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void t4_servo_init(void);
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void t4_servo_off(void);
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int t4_servo_get(unsigned int channel);
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int t4_servo_set(unsigned int channel, unsigned int duty);
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int t4_servo_set_io
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( unsigned char channel
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, unsigned char port
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, unsigned char ddr
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, unsigned char pin
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);
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#endif /* __T4_SERVO_H__ */
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