Little-Wire
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littleWire_servo.c
1 /*
2  Higher level servo driving library for Little Wire.
3 
4  Copyright (C) <2013> ihsan Kehribar <ihsan@kehribar.me>
5 
6  Permission is hereby granted, free of charge, to any person obtaining a copy of
7  this software and associated documentation files (the "Software"), to deal in
8  the Software without restriction, including without limitation the rights to
9  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
10  of the Software, and to permit persons to whom the Software is furnished to do
11  so, subject to the following conditions:
12 
13  The above copyright notice and this permission notice shall be included in all
14  copies or substantial portions of the Software.
15 
16  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22  SOFTWARE.
23 */
24 
25 #include "littleWire_servo.h"
26 
27 /********************************************************************************
28 * Useful definitions
29 ********************************************************************************/
30 const float MIN_LIMIT = 0.45; // in miliseconds
31 const float MAX_LIMIT = 2.45; // in miliseconds
32 const float STEP_SIZE = 0.062; // in miliseconds
33 const float RANGE = 180.0; // in degrees
34 /*******************************************************************************/
35 
36 /********************************************************************************
37 * Servo module initialization
38 ********************************************************************************/
39 void servo_init(littleWire* lwHandle)
40 {
41  pwm_init(lwHandle); // Initialize the PWM hardware.
42  pinMode(lwHandle,PWMA,OUTPUT); pinMode(lwHandle,PWMB,OUTPUT); // Set PWM pins output.
43  pwm_updatePrescaler(lwHandle,1024); // Make sure the PWM prescaler is set correctly.
44 }
45 /*******************************************************************************/
46 
47 /********************************************************************************
48 * Servo locations update
49 * locationChannelA in degrees
50 * locationChannelB in degrees
51 ********************************************************************************/
52 void servo_updateLocation(littleWire* lwHandle,unsigned char locationChannelA,unsigned char locationChannelB)
53 {
54  locationChannelA=(((locationChannelA/RANGE)*(MAX_LIMIT-MIN_LIMIT))+MIN_LIMIT)/STEP_SIZE;
55  locationChannelB=(((locationChannelB/RANGE)*(MAX_LIMIT-MIN_LIMIT))+MIN_LIMIT)/STEP_SIZE;
56  pwm_updateCompare(lwHandle,locationChannelA,locationChannelB);
57 }
58 /*******************************************************************************/