Patrick Thomas / PPMout

A PPM driver for the K64F that uses the CMT module

PPMout.h@2:4570e00696b9, 2016-09-06 (annotated)

Committer:
Padman
Date:
Tue Sep 06 16:54:00 2016 +0000
Revision:
2:4570e00696b9
Parent:
0:04365c9c9994 
Changed frame parameters

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Padman 0:04365c9c9994 1 /**
Padman 0:04365c9c9994 2 * @file PPMout.h
Padman 0:04365c9c9994 3 * @brief PPMout - PPM signal generator for K64F
Padman 0:04365c9c9994 4 * @author Patrick Thomas
Padman 0:04365c9c9994 5 * @version 1.0
Padman 0:04365c9c9994 6 * @see
Padman 0:04365c9c9994 7 *
Padman 0:04365c9c9994 8 * Copyright (c) 2016
Padman 0:04365c9c9994 9 *
Padman 0:04365c9c9994 10 * Licensed under the Apache License, Version 2.0 (the "License");
Padman 0:04365c9c9994 11 * you may not use this file except in compliance with the License.
Padman 0:04365c9c9994 12 * You may obtain a copy of the License at
Padman 0:04365c9c9994 13 *
Padman 0:04365c9c9994 14 * http://www.apache.org/licenses/LICENSE-2.0
Padman 0:04365c9c9994 15 *
Padman 0:04365c9c9994 16 * Unless required by applicable law or agreed to in writing, software
Padman 0:04365c9c9994 17 * distributed under the License is distributed on an "AS IS" BASIS,
Padman 0:04365c9c9994 18 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
Padman 0:04365c9c9994 19 * See the License for the specific language governing permissions and
Padman 0:04365c9c9994 20 * limitations under the License.
Padman 0:04365c9c9994 21 */
Padman 0:04365c9c9994 22
Padman 0:04365c9c9994 23 #ifndef PPMOUT_H
Padman 0:04365c9c9994 24 #define PPMOUT_H
Padman 0:04365c9c9994 25
Padman 0:04365c9c9994 26 #include "mbed.h"
Padman 0:04365c9c9994 27
Padman 0:04365c9c9994 28 #define PIN(n,min,max) ((n) > (max) ? max : ((n) < (min) ? (min) : (n)))
Padman 0:04365c9c9994 29
Padman 0:04365c9c9994 30 // System clock
Padman 0:04365c9c9994 31 #define BUS_CLOCK 60000000
Padman 0:04365c9c9994 32 #define CLOCK_DIVIDER 12
Padman 0:04365c9c9994 33 #define CMT_PPS_VAL (CLOCK_DIVIDER - 1)
Padman 0:04365c9c9994 34
Padman 0:04365c9c9994 35 // Step array
Padman 0:04365c9c9994 36 #define CHANNELS 8
Padman 0:04365c9c9994 37 #define ARRAY_SIZE (CHANNELS + 1)
Padman 0:04365c9c9994 38
Padman 0:04365c9c9994 39 // Time parameters
Padman 0:04365c9c9994 40 #define STEPS_PER_MS (((BUS_CLOCK/CLOCK_DIVIDER)/8)/1000)
Padman 2:4570e00696b9 41 #define GAP_LENGTH_MS 0.3
Padman 2:4570e00696b9 42 #define FRAME_LENGTH_MS 22.5
Padman 0:04365c9c9994 43
Padman 0:04365c9c9994 44 // PPM parameters
Padman 0:04365c9c9994 45 #define PPM_RANGE_MS 1
Padman 2:4570e00696b9 46 #define PPM_ZERO_MS 0.7
Padman 0:04365c9c9994 47
Padman 0:04365c9c9994 48 // Derived step parameters
Padman 0:04365c9c9994 49 #define RANGE_STEPS (PPM_RANGE_MS*STEPS_PER_MS)
Padman 0:04365c9c9994 50 #define ZERO_STEPS (PPM_ZERO_MS*STEPS_PER_MS)
Padman 0:04365c9c9994 51 #define GAP_STEPS (int) (GAP_LENGTH_MS*STEPS_PER_MS)
Padman 0:04365c9c9994 52 #define TOTAL_GAP_STEPS (GAP_STEPS*ARRAY_SIZE)
Padman 0:04365c9c9994 53 #define FRAME_STEPS (FRAME_LENGTH_MS*STEPS_PER_MS)
Padman 0:04365c9c9994 54 #define MAX_NON_GAP_STEPS (FRAME_STEPS - TOTAL_GAP_STEPS)
Padman 0:04365c9c9994 55
Padman 0:04365c9c9994 56 /** A library for producing PPM output on the K64F (pin PTD7) using the CMT (Carrier/Modulator Transmitter) module
Padman 0:04365c9c9994 57 *
Padman 0:04365c9c9994 58 * Example:
Padman 0:04365c9c9994 59 * @code
Padman 0:04365c9c9994 60 * #include "mbed.h"
Padman 0:04365c9c9994 61 * #include "PPMout.h"
Padman 0:04365c9c9994 62 *
Padman 0:04365c9c9994 63 * PPMout myPPM;
Padman 0:04365c9c9994 64 * Serial pc(USBTX, USBRX);
Padman 0:04365c9c9994 65 *
Padman 0:04365c9c9994 66 * int main()
Padman 0:04365c9c9994 67 * {
Padman 0:04365c9c9994 68 * while(1) {
Padman 0:04365c9c9994 69 *
Padman 0:04365c9c9994 70 * char buffer[128];
Padman 0:04365c9c9994 71 * float f;
Padman 0:04365c9c9994 72 *
Padman 0:04365c9c9994 73 * pc.gets(buffer, 5);
Padman 0:04365c9c9994 74 * f = (float) atof(buffer);
Padman 0:04365c9c9994 75 *
Padman 0:04365c9c9994 76 * myPPM.update_channel(0, f);
Padman 0:04365c9c9994 77 * }
Padman 0:04365c9c9994 78 * }
Padman 0:04365c9c9994 79 * @endcode
Padman 0:04365c9c9994 80 */
Padman 0:04365c9c9994 81
Padman 0:04365c9c9994 82 class PPMout {
Padman 0:04365c9c9994 83
Padman 0:04365c9c9994 84 private:
Padman 0:04365c9c9994 85
Padman 0:04365c9c9994 86 static int count_array[ARRAY_SIZE];
Padman 0:04365c9c9994 87 static int counter;
Padman 0:04365c9c9994 88
Padman 0:04365c9c9994 89 static void CMT_IRQHandler();
Padman 0:04365c9c9994 90 void init();
Padman 0:04365c9c9994 91 void set_sync_length();
Padman 0:04365c9c9994 92
Padman 0:04365c9c9994 93 public:
Padman 0:04365c9c9994 94
Padman 0:04365c9c9994 95 /** Create PPMout instance
Padman 0:04365c9c9994 96 */
Padman 0:04365c9c9994 97 PPMout();
Padman 0:04365c9c9994 98
Padman 0:04365c9c9994 99 /** Update a PPM channel value
Padman 0:04365c9c9994 100 * @param channel The channel to update (0-7)
Padman 0:04365c9c9994 101 * @param value The new value for the channel (0-1)
Padman 0:04365c9c9994 102 */
Padman 0:04365c9c9994 103 void update_channel(int channel, float value);
Padman 0:04365c9c9994 104 };
Padman 0:04365c9c9994 105
Padman 0:04365c9c9994 106 #endif