Johannes Stratmann / mbed-dev

added prescaler for 16 bit pwm in LPC1347 target

Fork of mbed-dev by mbed official

api/AnalogOut.h@147:ba84b7dc41a7, 2016-09-10 (annotated)

Committer:
JojoS
Date:
Sat Sep 10 15:32:04 2016 +0000
Revision:
147:ba84b7dc41a7
Parent:
144:ef7eb2e8f9f7 
added prescaler for 16 bit timers (solution as in LPC11xx), default prescaler 31 for max 28 ms period time

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 144:ef7eb2e8f9f7 1 /* mbed Microcontroller Library
<> 144:ef7eb2e8f9f7 2 * Copyright (c) 2006-2013 ARM Limited
<> 144:ef7eb2e8f9f7 3 *
<> 144:ef7eb2e8f9f7 4 * Licensed under the Apache License, Version 2.0 (the "License");
<> 144:ef7eb2e8f9f7 5 * you may not use this file except in compliance with the License.
<> 144:ef7eb2e8f9f7 6 * You may obtain a copy of the License at
<> 144:ef7eb2e8f9f7 7 *
<> 144:ef7eb2e8f9f7 8 * http://www.apache.org/licenses/LICENSE-2.0
<> 144:ef7eb2e8f9f7 9 *
<> 144:ef7eb2e8f9f7 10 * Unless required by applicable law or agreed to in writing, software
<> 144:ef7eb2e8f9f7 11 * distributed under the License is distributed on an "AS IS" BASIS,
<> 144:ef7eb2e8f9f7 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 144:ef7eb2e8f9f7 13 * See the License for the specific language governing permissions and
<> 144:ef7eb2e8f9f7 14 * limitations under the License.
<> 144:ef7eb2e8f9f7 15 */
<> 144:ef7eb2e8f9f7 16 #ifndef MBED_ANALOGOUT_H
<> 144:ef7eb2e8f9f7 17 #define MBED_ANALOGOUT_H
<> 144:ef7eb2e8f9f7 18
<> 144:ef7eb2e8f9f7 19 #include "platform.h"
<> 144:ef7eb2e8f9f7 20
<> 144:ef7eb2e8f9f7 21 #if DEVICE_ANALOGOUT
<> 144:ef7eb2e8f9f7 22
<> 144:ef7eb2e8f9f7 23 #include "analogout_api.h"
<> 144:ef7eb2e8f9f7 24 #include "PlatformMutex.h"
<> 144:ef7eb2e8f9f7 25
<> 144:ef7eb2e8f9f7 26 namespace mbed {
<> 144:ef7eb2e8f9f7 27
<> 144:ef7eb2e8f9f7 28 /** An analog output, used for setting the voltage on a pin
<> 144:ef7eb2e8f9f7 29 *
<> 144:ef7eb2e8f9f7 30 * @Note Synchronization level: Thread safe
<> 144:ef7eb2e8f9f7 31 *
<> 144:ef7eb2e8f9f7 32 * Example:
<> 144:ef7eb2e8f9f7 33 * @code
<> 144:ef7eb2e8f9f7 34 * // Make a sawtooth output
<> 144:ef7eb2e8f9f7 35 *
<> 144:ef7eb2e8f9f7 36 * #include "mbed.h"
<> 144:ef7eb2e8f9f7 37 *
<> 144:ef7eb2e8f9f7 38 * AnalogOut tri(p18);
<> 144:ef7eb2e8f9f7 39 * int main() {
<> 144:ef7eb2e8f9f7 40 * while(1) {
<> 144:ef7eb2e8f9f7 41 * tri = tri + 0.01;
<> 144:ef7eb2e8f9f7 42 * wait_us(1);
<> 144:ef7eb2e8f9f7 43 * if(tri == 1) {
<> 144:ef7eb2e8f9f7 44 * tri = 0;
<> 144:ef7eb2e8f9f7 45 * }
<> 144:ef7eb2e8f9f7 46 * }
<> 144:ef7eb2e8f9f7 47 * }
<> 144:ef7eb2e8f9f7 48 * @endcode
<> 144:ef7eb2e8f9f7 49 */
<> 144:ef7eb2e8f9f7 50 class AnalogOut {
<> 144:ef7eb2e8f9f7 51
<> 144:ef7eb2e8f9f7 52 public:
<> 144:ef7eb2e8f9f7 53
<> 144:ef7eb2e8f9f7 54 /** Create an AnalogOut connected to the specified pin
<> 144:ef7eb2e8f9f7 55 *
<> 144:ef7eb2e8f9f7 56 * @param AnalogOut pin to connect to (18)
<> 144:ef7eb2e8f9f7 57 */
<> 144:ef7eb2e8f9f7 58 AnalogOut(PinName pin) {
<> 144:ef7eb2e8f9f7 59 analogout_init(&_dac, pin);
<> 144:ef7eb2e8f9f7 60 }
<> 144:ef7eb2e8f9f7 61
<> 144:ef7eb2e8f9f7 62 /** Set the output voltage, specified as a percentage (float)
<> 144:ef7eb2e8f9f7 63 *
<> 144:ef7eb2e8f9f7 64 * @param value A floating-point value representing the output voltage,
<> 144:ef7eb2e8f9f7 65 * specified as a percentage. The value should lie between
<> 144:ef7eb2e8f9f7 66 * 0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
<> 144:ef7eb2e8f9f7 67 * Values outside this range will be saturated to 0.0f or 1.0f.
<> 144:ef7eb2e8f9f7 68 */
<> 144:ef7eb2e8f9f7 69 void write(float value) {
<> 144:ef7eb2e8f9f7 70 lock();
<> 144:ef7eb2e8f9f7 71 analogout_write(&_dac, value);
<> 144:ef7eb2e8f9f7 72 unlock();
<> 144:ef7eb2e8f9f7 73 }
<> 144:ef7eb2e8f9f7 74
<> 144:ef7eb2e8f9f7 75 /** Set the output voltage, represented as an unsigned short in the range [0x0, 0xFFFF]
<> 144:ef7eb2e8f9f7 76 *
<> 144:ef7eb2e8f9f7 77 * @param value 16-bit unsigned short representing the output voltage,
<> 144:ef7eb2e8f9f7 78 * normalised to a 16-bit value (0x0000 = 0v, 0xFFFF = 3.3v)
<> 144:ef7eb2e8f9f7 79 */
<> 144:ef7eb2e8f9f7 80 void write_u16(unsigned short value) {
<> 144:ef7eb2e8f9f7 81 lock();
<> 144:ef7eb2e8f9f7 82 analogout_write_u16(&_dac, value);
<> 144:ef7eb2e8f9f7 83 unlock();
<> 144:ef7eb2e8f9f7 84 }
<> 144:ef7eb2e8f9f7 85
<> 144:ef7eb2e8f9f7 86 /** Return the current output voltage setting, measured as a percentage (float)
<> 144:ef7eb2e8f9f7 87 *
<> 144:ef7eb2e8f9f7 88 * @returns
<> 144:ef7eb2e8f9f7 89 * A floating-point value representing the current voltage being output on the pin,
<> 144:ef7eb2e8f9f7 90 * measured as a percentage. The returned value will lie between
<> 144:ef7eb2e8f9f7 91 * 0.0f (representing 0v / 0%) and 1.0f (representing 3.3v / 100%).
<> 144:ef7eb2e8f9f7 92 *
<> 144:ef7eb2e8f9f7 93 * @note
<> 144:ef7eb2e8f9f7 94 * This value may not match exactly the value set by a previous write().
<> 144:ef7eb2e8f9f7 95 */
<> 144:ef7eb2e8f9f7 96 float read() {
<> 144:ef7eb2e8f9f7 97 lock();
<> 144:ef7eb2e8f9f7 98 float ret = analogout_read(&_dac);
<> 144:ef7eb2e8f9f7 99 unlock();
<> 144:ef7eb2e8f9f7 100 return ret;
<> 144:ef7eb2e8f9f7 101 }
<> 144:ef7eb2e8f9f7 102
<> 144:ef7eb2e8f9f7 103 /** An operator shorthand for write()
<> 144:ef7eb2e8f9f7 104 */
<> 144:ef7eb2e8f9f7 105 AnalogOut& operator= (float percent) {
<> 144:ef7eb2e8f9f7 106 // Underlying write call is thread safe
<> 144:ef7eb2e8f9f7 107 write(percent);
<> 144:ef7eb2e8f9f7 108 return *this;
<> 144:ef7eb2e8f9f7 109 }
<> 144:ef7eb2e8f9f7 110
<> 144:ef7eb2e8f9f7 111 AnalogOut& operator= (AnalogOut& rhs) {
<> 144:ef7eb2e8f9f7 112 // Underlying write call is thread safe
<> 144:ef7eb2e8f9f7 113 write(rhs.read());
<> 144:ef7eb2e8f9f7 114 return *this;
<> 144:ef7eb2e8f9f7 115 }
<> 144:ef7eb2e8f9f7 116
<> 144:ef7eb2e8f9f7 117 /** An operator shorthand for read()
<> 144:ef7eb2e8f9f7 118 */
<> 144:ef7eb2e8f9f7 119 operator float() {
<> 144:ef7eb2e8f9f7 120 // Underlying read call is thread safe
<> 144:ef7eb2e8f9f7 121 return read();
<> 144:ef7eb2e8f9f7 122 }
<> 144:ef7eb2e8f9f7 123
<> 144:ef7eb2e8f9f7 124 virtual ~AnalogOut() {
<> 144:ef7eb2e8f9f7 125 // Do nothing
<> 144:ef7eb2e8f9f7 126 }
<> 144:ef7eb2e8f9f7 127
<> 144:ef7eb2e8f9f7 128 protected:
<> 144:ef7eb2e8f9f7 129
<> 144:ef7eb2e8f9f7 130 virtual void lock() {
<> 144:ef7eb2e8f9f7 131 _mutex.lock();
<> 144:ef7eb2e8f9f7 132 }
<> 144:ef7eb2e8f9f7 133
<> 144:ef7eb2e8f9f7 134 virtual void unlock() {
<> 144:ef7eb2e8f9f7 135 _mutex.unlock();
<> 144:ef7eb2e8f9f7 136 }
<> 144:ef7eb2e8f9f7 137
<> 144:ef7eb2e8f9f7 138 dac_t _dac;
<> 144:ef7eb2e8f9f7 139 PlatformMutex _mutex;
<> 144:ef7eb2e8f9f7 140 };
<> 144:ef7eb2e8f9f7 141
<> 144:ef7eb2e8f9f7 142 } // namespace mbed
<> 144:ef7eb2e8f9f7 143
<> 144:ef7eb2e8f9f7 144 #endif
<> 144:ef7eb2e8f9f7 145
<> 144:ef7eb2e8f9f7 146 #endif