Johannes Stratmann / mbed-dev

added prescaler for 16 bit pwm in LPC1347 target

Fork of mbed-dev by mbed official

targets/hal/TARGET_Maxim/TARGET_MAX32620/pwmout_api.c@144:ef7eb2e8f9f7, 2016-09-02 (annotated)

Committer:
<>
Date:
Fri Sep 02 15:07:44 2016 +0100
Revision:
144:ef7eb2e8f9f7
This updates the lib to the mbed lib v125

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 144:ef7eb2e8f9f7 1 /*******************************************************************************
<> 144:ef7eb2e8f9f7 2 * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
<> 144:ef7eb2e8f9f7 3 *
<> 144:ef7eb2e8f9f7 4 * Permission is hereby granted, free of charge, to any person obtaining a
<> 144:ef7eb2e8f9f7 5 * copy of this software and associated documentation files (the "Software"),
<> 144:ef7eb2e8f9f7 6 * to deal in the Software without restriction, including without limitation
<> 144:ef7eb2e8f9f7 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
<> 144:ef7eb2e8f9f7 8 * and/or sell copies of the Software, and to permit persons to whom the
<> 144:ef7eb2e8f9f7 9 * Software is furnished to do so, subject to the following conditions:
<> 144:ef7eb2e8f9f7 10 *
<> 144:ef7eb2e8f9f7 11 * The above copyright notice and this permission notice shall be included
<> 144:ef7eb2e8f9f7 12 * in all copies or substantial portions of the Software.
<> 144:ef7eb2e8f9f7 13 *
<> 144:ef7eb2e8f9f7 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
<> 144:ef7eb2e8f9f7 15 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
<> 144:ef7eb2e8f9f7 16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
<> 144:ef7eb2e8f9f7 17 * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
<> 144:ef7eb2e8f9f7 18 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
<> 144:ef7eb2e8f9f7 19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
<> 144:ef7eb2e8f9f7 20 * OTHER DEALINGS IN THE SOFTWARE.
<> 144:ef7eb2e8f9f7 21 *
<> 144:ef7eb2e8f9f7 22 * Except as contained in this notice, the name of Maxim Integrated
<> 144:ef7eb2e8f9f7 23 * Products, Inc. shall not be used except as stated in the Maxim Integrated
<> 144:ef7eb2e8f9f7 24 * Products, Inc. Branding Policy.
<> 144:ef7eb2e8f9f7 25 *
<> 144:ef7eb2e8f9f7 26 * The mere transfer of this software does not imply any licenses
<> 144:ef7eb2e8f9f7 27 * of trade secrets, proprietary technology, copyrights, patents,
<> 144:ef7eb2e8f9f7 28 * trademarks, maskwork rights, or any other form of intellectual
<> 144:ef7eb2e8f9f7 29 * property whatsoever. Maxim Integrated Products, Inc. retains all
<> 144:ef7eb2e8f9f7 30 * ownership rights.
<> 144:ef7eb2e8f9f7 31 *******************************************************************************
<> 144:ef7eb2e8f9f7 32 */
<> 144:ef7eb2e8f9f7 33
<> 144:ef7eb2e8f9f7 34 #include "mbed_assert.h"
<> 144:ef7eb2e8f9f7 35 #include "cmsis.h"
<> 144:ef7eb2e8f9f7 36 #include "pwmout_api.h"
<> 144:ef7eb2e8f9f7 37 #include "pinmap.h"
<> 144:ef7eb2e8f9f7 38 #include "clkman_regs.h"
<> 144:ef7eb2e8f9f7 39 #include "PeripheralPins.h"
<> 144:ef7eb2e8f9f7 40
<> 144:ef7eb2e8f9f7 41 //******************************************************************************
<> 144:ef7eb2e8f9f7 42 void pwmout_init(pwmout_t* obj, PinName pin)
<> 144:ef7eb2e8f9f7 43 {
<> 144:ef7eb2e8f9f7 44 // Make sure the pin is free for GPIO use
<> 144:ef7eb2e8f9f7 45 unsigned int port = (unsigned int)pin >> PORT_SHIFT;
<> 144:ef7eb2e8f9f7 46 unsigned int port_pin = (unsigned int)pin & ~(0xFFFFFFFF << PORT_SHIFT);
<> 144:ef7eb2e8f9f7 47 MBED_ASSERT(MXC_GPIO->free[port] & (0x1 << port_pin));
<> 144:ef7eb2e8f9f7 48
<> 144:ef7eb2e8f9f7 49 int i = 0;
<> 144:ef7eb2e8f9f7 50 PinMap pwm = PinMap_PWM[0];
<> 144:ef7eb2e8f9f7 51
<> 144:ef7eb2e8f9f7 52 // Check if there is a pulse train already active on this port
<> 144:ef7eb2e8f9f7 53 int pin_func = (MXC_GPIO->func_sel[port] & (0xF << (port_pin*4))) >> (port_pin*4);
<> 144:ef7eb2e8f9f7 54 MBED_ASSERT((pin_func < 1) || (pin_func > 3));
<> 144:ef7eb2e8f9f7 55
<> 144:ef7eb2e8f9f7 56 // Search through PinMap_PWM to find the pin
<> 144:ef7eb2e8f9f7 57 while (pwm.pin != pin) {
<> 144:ef7eb2e8f9f7 58 pwm = PinMap_PWM[++i];
<> 144:ef7eb2e8f9f7 59 }
<> 144:ef7eb2e8f9f7 60
<> 144:ef7eb2e8f9f7 61 // Find a free PT instance on this pin
<> 144:ef7eb2e8f9f7 62 while (pwm.pin == pin) {
<> 144:ef7eb2e8f9f7 63
<> 144:ef7eb2e8f9f7 64 // Check to see if this PT instance is free
<> 144:ef7eb2e8f9f7 65 if (((mxc_pt_regs_t*)pwm.peripheral)->rate_length & MXC_F_PT_RATE_LENGTH_MODE) {
<> 144:ef7eb2e8f9f7 66 break;
<> 144:ef7eb2e8f9f7 67 }
<> 144:ef7eb2e8f9f7 68
<> 144:ef7eb2e8f9f7 69 pwm = PinMap_PWM[++i];
<> 144:ef7eb2e8f9f7 70
<> 144:ef7eb2e8f9f7 71 // Raise an assertion if we can not allocate another PT instance.
<> 144:ef7eb2e8f9f7 72 MBED_ASSERT(pwm.pin == pin);
<> 144:ef7eb2e8f9f7 73 }
<> 144:ef7eb2e8f9f7 74
<> 144:ef7eb2e8f9f7 75 // Enable the clock
<> 144:ef7eb2e8f9f7 76 MXC_CLKMAN->sys_clk_ctrl_7_pt = MXC_S_CLKMAN_CLK_SCALE_DIV_1;
<> 144:ef7eb2e8f9f7 77
<> 144:ef7eb2e8f9f7 78 // Set the obj pointer to the propper PWM instance
<> 144:ef7eb2e8f9f7 79 obj->pwm = (mxc_pt_regs_t*)pwm.peripheral;
<> 144:ef7eb2e8f9f7 80
<> 144:ef7eb2e8f9f7 81 // Initialize object period and pulse width
<> 144:ef7eb2e8f9f7 82 obj->period = -1;
<> 144:ef7eb2e8f9f7 83 obj->pulse_width = -1;
<> 144:ef7eb2e8f9f7 84
<> 144:ef7eb2e8f9f7 85 // Disable the output
<> 144:ef7eb2e8f9f7 86 obj->pwm->train = 0x0;
<> 144:ef7eb2e8f9f7 87 obj->pwm->rate_length = 0x0;
<> 144:ef7eb2e8f9f7 88
<> 144:ef7eb2e8f9f7 89 // Configure the pin
<> 144:ef7eb2e8f9f7 90 pin_mode(pin, (PinMode)PullNone);
<> 144:ef7eb2e8f9f7 91 pin_function(pin, pwm.function);
<> 144:ef7eb2e8f9f7 92
<> 144:ef7eb2e8f9f7 93 // default to 20ms: standard for servos, and fine for e.g. brightness control
<> 144:ef7eb2e8f9f7 94 pwmout_period_us(obj, 20000);
<> 144:ef7eb2e8f9f7 95 pwmout_write (obj, 0);
<> 144:ef7eb2e8f9f7 96
<> 144:ef7eb2e8f9f7 97 // Set the drive mode to normal
<> 144:ef7eb2e8f9f7 98 MXC_SET_FIELD(&MXC_GPIO->out_mode[port], (0x7 << (port_pin*4)), (MXC_V_GPIO_OUT_MODE_NORMAL << (port_pin*4)));
<> 144:ef7eb2e8f9f7 99
<> 144:ef7eb2e8f9f7 100 // Enable this PWM channel
<> 144:ef7eb2e8f9f7 101 MXC_PTG->enable |= (1 << MXC_PT_GET_IDX(obj->pwm));
<> 144:ef7eb2e8f9f7 102 }
<> 144:ef7eb2e8f9f7 103
<> 144:ef7eb2e8f9f7 104 //******************************************************************************
<> 144:ef7eb2e8f9f7 105 void pwmout_free(pwmout_t* obj)
<> 144:ef7eb2e8f9f7 106 {
<> 144:ef7eb2e8f9f7 107 // Set the registers to the reset value
<> 144:ef7eb2e8f9f7 108 obj->pwm->train = 0;
<> 144:ef7eb2e8f9f7 109 obj->pwm->rate_length = 0x08000000;
<> 144:ef7eb2e8f9f7 110 }
<> 144:ef7eb2e8f9f7 111
<> 144:ef7eb2e8f9f7 112 //******************************************************************************
<> 144:ef7eb2e8f9f7 113 static void pwmout_update(pwmout_t* obj)
<> 144:ef7eb2e8f9f7 114 {
<> 144:ef7eb2e8f9f7 115 // Calculate and set the divider ratio
<> 144:ef7eb2e8f9f7 116 int div = (obj->period * (SystemCoreClock/1000000))/32;
<> 144:ef7eb2e8f9f7 117 if (div < 2){
<> 144:ef7eb2e8f9f7 118 div = 2;
<> 144:ef7eb2e8f9f7 119 }
<> 144:ef7eb2e8f9f7 120 MXC_SET_FIELD(&obj->pwm->rate_length, MXC_F_PT_RATE_LENGTH_RATE_CONTROL, div);
<> 144:ef7eb2e8f9f7 121
<> 144:ef7eb2e8f9f7 122 // Change the duty cycle to adjust the pulse width
<> 144:ef7eb2e8f9f7 123 obj->pwm->train = (0xFFFFFFFF << (32-((32*obj->pulse_width)/obj->period)));
<> 144:ef7eb2e8f9f7 124 }
<> 144:ef7eb2e8f9f7 125
<> 144:ef7eb2e8f9f7 126
<> 144:ef7eb2e8f9f7 127 //******************************************************************************
<> 144:ef7eb2e8f9f7 128 void pwmout_write(pwmout_t* obj, float percent)
<> 144:ef7eb2e8f9f7 129 {
<> 144:ef7eb2e8f9f7 130 // Saturate percent if outside of range
<> 144:ef7eb2e8f9f7 131 if (percent < 0.0f) {
<> 144:ef7eb2e8f9f7 132 percent = 0.0f;
<> 144:ef7eb2e8f9f7 133 } else if(percent > 1.0f) {
<> 144:ef7eb2e8f9f7 134 percent = 1.0f;
<> 144:ef7eb2e8f9f7 135 }
<> 144:ef7eb2e8f9f7 136
<> 144:ef7eb2e8f9f7 137 // Resize the pulse width to set the duty cycle
<> 144:ef7eb2e8f9f7 138 pwmout_pulsewidth_us(obj, (int)(percent*obj->period));
<> 144:ef7eb2e8f9f7 139 }
<> 144:ef7eb2e8f9f7 140
<> 144:ef7eb2e8f9f7 141 //******************************************************************************
<> 144:ef7eb2e8f9f7 142 float pwmout_read(pwmout_t* obj)
<> 144:ef7eb2e8f9f7 143 {
<> 144:ef7eb2e8f9f7 144 // Check for when pulsewidth or period equals 0
<> 144:ef7eb2e8f9f7 145 if ((obj->pulse_width == 0) || (obj->period == 0)){
<> 144:ef7eb2e8f9f7 146 return 0;
<> 144:ef7eb2e8f9f7 147 }
<> 144:ef7eb2e8f9f7 148
<> 144:ef7eb2e8f9f7 149 // Return the duty cycle
<> 144:ef7eb2e8f9f7 150 return ((float)obj->pulse_width / (float)obj->period);
<> 144:ef7eb2e8f9f7 151 }
<> 144:ef7eb2e8f9f7 152
<> 144:ef7eb2e8f9f7 153 //******************************************************************************
<> 144:ef7eb2e8f9f7 154 void pwmout_period(pwmout_t* obj, float seconds)
<> 144:ef7eb2e8f9f7 155 {
<> 144:ef7eb2e8f9f7 156 pwmout_period_us(obj, (int)(seconds * 1000000.0f));
<> 144:ef7eb2e8f9f7 157 }
<> 144:ef7eb2e8f9f7 158
<> 144:ef7eb2e8f9f7 159 //******************************************************************************
<> 144:ef7eb2e8f9f7 160 void pwmout_period_ms(pwmout_t* obj, int ms)
<> 144:ef7eb2e8f9f7 161 {
<> 144:ef7eb2e8f9f7 162 pwmout_period_us(obj, ms*1000);
<> 144:ef7eb2e8f9f7 163 }
<> 144:ef7eb2e8f9f7 164
<> 144:ef7eb2e8f9f7 165 //******************************************************************************
<> 144:ef7eb2e8f9f7 166 void pwmout_period_us(pwmout_t* obj, int us)
<> 144:ef7eb2e8f9f7 167 {
<> 144:ef7eb2e8f9f7 168 // Check the range of the period
<> 144:ef7eb2e8f9f7 169 MBED_ASSERT((us >= 0) && (us <= (int)(SystemCoreClock/32)));
<> 144:ef7eb2e8f9f7 170
<> 144:ef7eb2e8f9f7 171 // Set pulse width to half the period if uninitialized
<> 144:ef7eb2e8f9f7 172 if (obj->pulse_width == -1) {
<> 144:ef7eb2e8f9f7 173 obj->pulse_width = us/2;
<> 144:ef7eb2e8f9f7 174 }
<> 144:ef7eb2e8f9f7 175
<> 144:ef7eb2e8f9f7 176 // Save the period
<> 144:ef7eb2e8f9f7 177 obj->period = us;
<> 144:ef7eb2e8f9f7 178
<> 144:ef7eb2e8f9f7 179 // Update the registers
<> 144:ef7eb2e8f9f7 180 pwmout_update(obj);
<> 144:ef7eb2e8f9f7 181 }
<> 144:ef7eb2e8f9f7 182
<> 144:ef7eb2e8f9f7 183 //******************************************************************************
<> 144:ef7eb2e8f9f7 184 void pwmout_pulsewidth(pwmout_t* obj, float seconds)
<> 144:ef7eb2e8f9f7 185 {
<> 144:ef7eb2e8f9f7 186 pwmout_pulsewidth_us(obj, (int)(seconds * 1000000.0f));
<> 144:ef7eb2e8f9f7 187 }
<> 144:ef7eb2e8f9f7 188
<> 144:ef7eb2e8f9f7 189 //******************************************************************************
<> 144:ef7eb2e8f9f7 190 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms)
<> 144:ef7eb2e8f9f7 191 {
<> 144:ef7eb2e8f9f7 192 pwmout_pulsewidth_us(obj, ms*1000);
<> 144:ef7eb2e8f9f7 193 }
<> 144:ef7eb2e8f9f7 194
<> 144:ef7eb2e8f9f7 195 //******************************************************************************
<> 144:ef7eb2e8f9f7 196 void pwmout_pulsewidth_us(pwmout_t* obj, int us)
<> 144:ef7eb2e8f9f7 197 {
<> 144:ef7eb2e8f9f7 198 // Check the range of the pulsewidth
<> 144:ef7eb2e8f9f7 199 MBED_ASSERT((us >= 0) && (us <= (int)(SystemCoreClock/32)));
<> 144:ef7eb2e8f9f7 200
<> 144:ef7eb2e8f9f7 201 // Initialize period to double the pulsewidth if uninitialized
<> 144:ef7eb2e8f9f7 202 if (obj->period == -1) {
<> 144:ef7eb2e8f9f7 203 obj->period = 2*us;
<> 144:ef7eb2e8f9f7 204 }
<> 144:ef7eb2e8f9f7 205
<> 144:ef7eb2e8f9f7 206 // Save the pulsewidth
<> 144:ef7eb2e8f9f7 207 obj->pulse_width = us;
<> 144:ef7eb2e8f9f7 208
<> 144:ef7eb2e8f9f7 209 // Update the register
<> 144:ef7eb2e8f9f7 210 pwmout_update(obj);
<> 144:ef7eb2e8f9f7 211 }