mbed/src/vendor/NXP/capi/pwmout_api.c

   1 /* mbed Microcontroller Library
   2  * Copyright (c) 2006-2013 ARM Limited
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 #include "pwmout_api.h"
  17
  18 #if DEVICE_PWMOUT
  19
  20 #include "cmsis.h"
  21 #include "pinmap.h"
  22 #include "error.h"
  23
  24 #define TCR_CNT_EN       0x00000001
  25 #define TCR_RESET        0x00000002
  26
  27 #if defined(TARGET_LPC1768) || defined(TARGET_LPC2368)
  28 //  PORT ID, PWM ID, Pin function
  29 static const PinMap PinMap_PWM[] = {
  30     {P1_18, PWM_1, 2},
  31     {P1_20, PWM_2, 2},
  32     {P1_21, PWM_3, 2},
  33     {P1_23, PWM_4, 2},
  34     {P1_24, PWM_5, 2},
  35     {P1_26, PWM_6, 2},
  36     {P2_0 , PWM_1, 1},
  37     {P2_1 , PWM_2, 1},
  38     {P2_2 , PWM_3, 1},
  39     {P2_3 , PWM_4, 1},
  40     {P2_4 , PWM_5, 1},
  41     {P2_5 , PWM_6, 1},
  42     {P3_25, PWM_2, 3},
  43     {P3_26, PWM_3, 3},
  44     {NC, NC, 0}
  45 };
  46
  47 __IO uint32_t *PWM_MATCH[] = {
  48     &(LPC_PWM1->MR0),
  49     &(LPC_PWM1->MR1),
  50     &(LPC_PWM1->MR2),
  51     &(LPC_PWM1->MR3),
  52     &(LPC_PWM1->MR4),
  53     &(LPC_PWM1->MR5),
  54     &(LPC_PWM1->MR6)
  55 };
  56
  57 #define TCR_PWM_EN       0x00000008
  58
  59 static unsigned int pwm_clock_mhz;
  60
  61 #elif defined(TARGET_LPC11U24)
  62 /* To have a PWM where we can change both the period and the duty cycle,
  63  * we need an entire timer. With the following conventions:
  64  *   * MR3 is used for the PWM period
  65  *   * MR0, MR1, MR2 are used for the duty cycle
  66  */
  67 static const PinMap PinMap_PWM[] = {
  68     /* CT16B0 */
  69     {P0_8 , PWM_1, 2}, {P1_13, PWM_1, 2},    /* MR0 */
  70     {P0_9 , PWM_2, 2}, {P1_14, PWM_2, 2},   /* MR1 */
  71     {P0_10, PWM_3, 3}, {P1_15, PWM_3, 2},   /* MR2 */
  72
  73     /* CT16B1 */
  74     {P0_21, PWM_4, 1},                      /* MR0 */
  75     {P0_22, PWM_5, 2}, {P1_23, PWM_5, 1},   /* MR1 */
  76
  77     /* CT32B0 */
  78     {P0_18, PWM_6, 2}, {P1_24, PWM_6, 1},   /* MR0 */
  79     {P0_19, PWM_7, 2}, {P1_25, PWM_7, 1},   /* MR1 */
  80     {P0_1 , PWM_8, 2}, {P1_26, PWM_8, 1},   /* MR2 */
  81
  82     /* CT32B1 */
  83     {P0_13, PWM_9 , 3}, {P1_0, PWM_9 , 1},  /* MR0 */
  84     {P0_14, PWM_10, 3}, {P1_1, PWM_10, 1},  /* MR1 */
  85     {P0_15, PWM_11, 3}, {P1_2, PWM_11, 1},  /* MR2 */
  86
  87     {NC, NC, 0}
  88 };
  89
  90 typedef struct {
  91     uint8_t timer;
  92     uint8_t mr;
  93 } timer_mr;
  94
  95 static timer_mr pwm_timer_map[11] = {
  96     {0, 0}, {0, 1}, {0, 2},
  97     {1, 0}, {1, 1},
  98     {2, 0}, {2, 1}, {2, 2},
  99     {3, 0}, {3, 1}, {3, 2},
 100 };
 101
 102 static LPC_CTxxBx_Type *Timers[4] = {
 103     LPC_CT16B0, LPC_CT16B1,
 104     LPC_CT32B0, LPC_CT32B1
 105 };
 106
 107 static unsigned int pwm_clock_mhz;
 108 #endif
 109
 110 void pwmout_init(pwmout_t* obj, PinName pin) {
 111     // determine the channel
 112     PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
 113     if (pwm == (uint32_t)NC)
 114         error("PwmOut pin mapping failed");
 115
 116 #if defined(TARGET_LPC1768) || defined(TARGET_LPC2368)
 117     obj->pwm = pwm;
 118     obj->MR = PWM_MATCH[pwm];
 119
 120     // ensure the power is on
 121     LPC_SC->PCONP |= 1 << 6;
 122
 123     // ensure clock to /4
 124     LPC_SC->PCLKSEL0 &= ~(0x3 << 12);     // pclk = /4
 125     LPC_PWM1->PR = 0;                     // no pre-scale
 126
 127     // ensure single PWM mode
 128     LPC_PWM1->MCR = 1 << 1; // reset TC on match 0
 129
 130     // enable the specific PWM output
 131     LPC_PWM1->PCR |= 1 << (8 + pwm);
 132
 133     pwm_clock_mhz = SystemCoreClock / 4000000;
 134
 135 #elif defined(TARGET_LPC11U24)
 136     obj->pwm = pwm;
 137
 138     // Timer registers
 139     timer_mr tid = pwm_timer_map[pwm];
 140     LPC_CTxxBx_Type *timer = Timers[tid.timer];
 141
 142     // Disable timer
 143     timer->TCR = 0;
 144
 145     // Power the correspondent timer
 146     LPC_SYSCON->SYSAHBCLKCTRL |= 1 << (tid.timer + 7);
 147
 148     /* Enable PWM function */
 149     timer->PWMC = (1 << 3)|(1 << 2)|(1 << 1)|(1 << 0);
 150
 151     /* Reset Functionality on MR3 controlling the PWM period */
 152     timer->MCR = 1 << 10;
 153
 154     pwm_clock_mhz = SystemCoreClock / 1000000;
 155 #endif
 156     // default to 20ms: standard for servos, and fine for e.g. brightness control
 157     pwmout_period_ms(obj, 20);
 158     pwmout_write    (obj, 0);
 159
 160     // Wire pinout
 161     pinmap_pinout(pin, PinMap_PWM);
 162 }
 163
 164 void pwmout_free(pwmout_t* obj) {
 165     // [TODO]
 166 }
 167
 168 void pwmout_write(pwmout_t* obj, float value) {
 169     if (value < 0.0) {
 170         value = 0.0;
 171     } else if (value > 1.0) {
 172         value = 1.0;
 173     }
 174
 175 #if defined(TARGET_LPC1768) || defined(TARGET_LPC2368)
 176     // set channel match to percentage
 177     uint32_t v = (uint32_t)((float)(LPC_PWM1->MR0) * value);
 178
 179     // workaround for PWM1[1] - Never make it equal MR0, else we get 1 cycle dropout
 180     if (v == LPC_PWM1->MR0) {
 181         v++;
 182     }
 183
 184     *obj->MR = v;
 185
 186     // accept on next period start
 187     LPC_PWM1->LER |= 1 << obj->pwm;
 188
 189 #elif defined(TARGET_LPC11U24)
 190     timer_mr tid = pwm_timer_map[obj->pwm];
 191     LPC_CTxxBx_Type *timer = Timers[tid.timer];
 192     uint32_t t_off = timer->MR3 - (uint32_t)((float)(timer->MR3) * value);
 193
 194     timer->TCR = TCR_RESET;
 195     timer->MR[tid.mr] = t_off;
 196     timer->TCR = TCR_CNT_EN;
 197 #endif
 198 }
 199
 200 float pwmout_read(pwmout_t* obj) {
 201     float v;
 202 #if defined(TARGET_LPC1768) || defined(TARGET_LPC2368)
 203     v = (float)(*obj->MR) / (float)(LPC_PWM1->MR0);
 204
 205 #elif defined(TARGET_LPC11U24)
 206     timer_mr tid = pwm_timer_map[obj->pwm];
 207     LPC_CTxxBx_Type *timer = Timers[tid.timer];
 208     v = (float)(timer->MR3 - timer->MR[tid.mr]) / (float)(timer->MR3);
 209
 210 #endif
 211
 212     return (v > 1.0) ? (1.0) : (v);
 213 }
 214
 215 void pwmout_period(pwmout_t* obj, float seconds) {
 216     pwmout_period_us(obj, seconds * 1000000.0f);
 217 }
 218
 219 void pwmout_period_ms(pwmout_t* obj, int ms) {
 220     pwmout_period_us(obj, ms * 1000);
 221 }
 222
 223 // Set the PWM period, keeping the duty cycle the same.
 224 void pwmout_period_us(pwmout_t* obj, int us) {
 225 #if defined(TARGET_LPC1768) || defined(TARGET_LPC2368)
 226     // calculate number of ticks
 227     uint32_t ticks = pwm_clock_mhz * us;
 228
 229     // set reset
 230     LPC_PWM1->TCR = TCR_RESET;
 231
 232     // set the global match register
 233     LPC_PWM1->MR0 = ticks;
 234
 235     // Scale the pulse width to preserve the duty ratio
 236     if (LPC_PWM1->MR0 > 0) {
 237         *obj->MR = (*obj->MR * ticks) / LPC_PWM1->MR0;
 238     }
 239
 240     // set the channel latch to update value at next period start
 241     LPC_PWM1->LER |= 1 << 0;
 242
 243     // enable counter and pwm, clear reset
 244     LPC_PWM1->TCR = TCR_CNT_EN | TCR_PWM_EN;
 245
 246 #elif defined(TARGET_LPC11U24)
 247     int i = 0;
 248     uint32_t period_ticks = pwm_clock_mhz * us;
 249
 250     timer_mr tid = pwm_timer_map[obj->pwm];
 251     LPC_CTxxBx_Type *timer = Timers[tid.timer];
 252     uint32_t old_period_ticks = timer->MR3;
 253
 254     timer->TCR = TCR_RESET;
 255     timer->MR3 = period_ticks;
 256
 257     // Scale the pulse width to preserve the duty ratio
 258     if (old_period_ticks > 0) {
 259         for (i=0; i<3; i++) {
 260             uint32_t t_off = period_ticks - (uint32_t)(((uint64_t)timer->MR[i] * (uint64_t)period_ticks) / (uint64_t)old_period_ticks);
 261             timer->MR[i] = t_off;
 262         }
 263     }
 264     timer->TCR = TCR_CNT_EN;
 265
 266 #endif
 267 }
 268
 269 void pwmout_pulsewidth(pwmout_t* obj, float seconds) {
 270     pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
 271 }
 272
 273 void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) {
 274     pwmout_pulsewidth_us(obj, ms * 1000);
 275 }
 276
 277 void pwmout_pulsewidth_us(pwmout_t* obj, int us) {
 278 #if defined(TARGET_LPC1768) || defined(TARGET_LPC2368)
 279     // calculate number of ticks
 280     uint32_t v = pwm_clock_mhz * us;
 281
 282     // workaround for PWM1[1] - Never make it equal MR0, else we get 1 cycle dropout
 283     if (v == LPC_PWM1->MR0) {
 284         v++;
 285     }
 286
 287     // set the match register value
 288     *obj->MR = v;
 289
 290     // set the channel latch to update value at next period start
 291     LPC_PWM1->LER |= 1 << obj->pwm;
 292
 293 #elif defined(TARGET_LPC11U24)
 294     uint32_t t_on = (uint32_t)(((uint64_t)SystemCoreClock * (uint64_t)us) / (uint64_t)1000000);
 295     timer_mr tid = pwm_timer_map[obj->pwm];
 296     LPC_CTxxBx_Type *timer = Timers[tid.timer];
 297
 298     timer->TCR = TCR_RESET;
 299     if (t_on > timer->MR3) {
 300         pwmout_period_us(obj, us);
 301     }
 302     uint32_t t_off = timer->MR3 - t_on;
 303     timer->MR[tid.mr] = t_off;
 304     timer->TCR = TCR_CNT_EN;
 305
 306 #endif
 307 }
 308
 309 #endif