/* mbed Microcontroller Library * Copyright (c) 2006-2013 ARM Limited * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * Ported to NXP LPC43XX by Micromint USA */ #include "mbed_assert.h" #include "pwmout_api.h" #include "cmsis.h" #include "pinmap.h" #include "mbed_error.h" // PWM implementation for the LPC43xx using State Configurable Timer (SCT) // * PWM_0 to PWM_15 on mbed use CTOUT_0 to CTOUT_15 outputs on LPC43xx // * Event 0 is PWM period, events 1 to PWM_EVENT_MAX are PWM channels // * Default is unified 32-bit timer, but could be configured to use // a 16-bit timer so a timer is available for other SCT functions // configuration options #define PWM_FREQ_BASE 1000000 // Base frequency 1 MHz = 1000000 #define PWM_MODE 1 // 0 = 32-bit, 1 = 16-bit low, 2 = 16-bit high // macros #define PWM_SETCOUNT(x) (x - 1) // set count value #define PWM_GETCOUNT(x) (x + 1) // get count value #if (PWM_MODE == 0) // unified 32-bit counter, events 1 to 15 #define PWM_EVENT_MAX (CONFIG_SCT_nEV - 1) // Max PWM channels #define PWM_CONFIG SCT_CONFIG_32BIT_COUNTER // default config #define PWM_CTRL &LPC_SCT->CTRL_U // control register #define PWM_HALT SCT_CTRL_HALT_L // halt counter #define PWM_CLEAR SCT_CTRL_CLRCTR_L // clock clear #define PWM_PRE(x) SCT_CTRL_PRE_L(x) // clock prescale #define PWM_EVT_MASK (1 << 12) // event control mask #define PWM_LIMIT &LPC_SCT->LIMIT_L // limit register #define PWM_MATCH(x) &LPC_SCT->MATCH[x].U // match register #define PWM_MR(x) &LPC_SCT->MATCHREL[x].U // 32-bit match reload register #elif (PWM_MODE == 1) // 16-bit low counter, events 1 to 7 #define PWM_EVENT_MAX (CONFIG_SCT_nEV/2 - 1) // Max PWM channels #define PWM_CONFIG SCT_CONFIG_16BIT_COUNTER // default config #define PWM_CTRL &LPC_SCT->CTRL_L // control register #define PWM_HALT SCT_CTRL_HALT_L // halt counter #define PWM_CLEAR SCT_CTRL_CLRCTR_L // clock clear #define PWM_PRE(x) SCT_CTRL_PRE_L(x) // clock prescale #define PWM_EVT_MASK (1 << 12) // event control mask #define PWM_LIMIT &LPC_SCT->LIMIT_L // limit register #define PWM_MATCH(x) &LPC_SCT->MATCH[x].L // match register #define PWM_MR(x) &LPC_SCT->MATCHREL[x].L // 16-bit match reload register #elif (PWM_MODE == 2) // 16-bit high counter, events 1 to 7 // [TODO] use events 8 to 15 on mode 2 #define PWM_EVENT_MAX (CONFIG_SCT_nEV/2 - 1) // Max PWM channels #define PWM_CONFIG SCT_CONFIG_16BIT_COUNTER // default config #define PWM_CTRL &LPC_SCT->CTRL_H // control register #define PWM_HALT SCT_CTRL_HALT_L // halt counter #define PWM_CLEAR SCT_CTRL_CLRCTR_L // clock clear #define PWM_PRE(x) SCT_CTRL_PRE_L(x) // clock prescale #define PWM_EVT_MASK ((1 << 4) | (1 << 12)) // event control mask #define PWM_LIMIT &LPC_SCT->LIMIT_H // limit register #define PWM_MATCH(x) &LPC_SCT->MATCH[x].H // match register #define PWM_MR(x) &LPC_SCT->MATCHREL[x].H // 16-bit match reload register #else #error "PWM mode not implemented" #endif #define PWM_MR0 PWM_MR(0) // MR register 0 is for period static uint8_t event = 0; // PORT ID, PWM ID, Pin function static const PinMap PinMap_PWM[] = { {P1_1, PWM_7, (SCU_PINIO_FAST | 1)}, {P1_2, PWM_6, (SCU_PINIO_FAST | 1)}, {P1_3, PWM_8, (SCU_PINIO_FAST | 1)}, {P1_4, PWM_9, (SCU_PINIO_FAST | 1)}, {P1_5, PWM_10, (SCU_PINIO_FAST | 1)}, {P1_7, PWM_13, (SCU_PINIO_FAST | 2)}, {P1_8, PWM_12, (SCU_PINIO_FAST | 2)}, {P1_9, PWM_11, (SCU_PINIO_FAST | 2)}, {P1_10, PWM_14, (SCU_PINIO_FAST | 2)}, {P1_11, PWM_15, (SCU_PINIO_FAST | 2)}, {P2_7, PWM_1, (SCU_PINIO_FAST | 1)}, {P2_8, PWM_0, (SCU_PINIO_FAST | 1)}, {P2_9, PWM_3, (SCU_PINIO_FAST | 1)}, {P2_10, PWM_2, (SCU_PINIO_FAST | 1)}, {P2_11, PWM_5, (SCU_PINIO_FAST | 1)}, {P2_12, PWM_4, (SCU_PINIO_FAST | 1)}, {P4_1, PWM_1, (SCU_PINIO_FAST | 1)}, {P4_2, PWM_0, (SCU_PINIO_FAST | 1)}, {P4_3, PWM_3, (SCU_PINIO_FAST | 1)}, {P4_4, PWM_2, (SCU_PINIO_FAST | 1)}, {P4_5, PWM_5, (SCU_PINIO_FAST | 1)}, {P4_6, PWM_4, (SCU_PINIO_FAST | 1)}, {P6_5, PWM_6, (SCU_PINIO_FAST | 1)}, {P6_12, PWM_7, (SCU_PINIO_FAST | 1)}, {P7_0, PWM_14, (SCU_PINIO_FAST | 1)}, {P7_1, PWM_15, (SCU_PINIO_FAST | 1)}, {P7_4, PWM_13, (SCU_PINIO_FAST | 1)}, {P7_5, PWM_12, (SCU_PINIO_FAST | 1)}, {P7_6, PWM_11, (SCU_PINIO_FAST | 1)}, {P7_7, PWM_8, (SCU_PINIO_FAST | 1)}, {PA_4, PWM_9, (SCU_PINIO_FAST | 1)}, {PB_0, PWM_10, (SCU_PINIO_FAST | 1)}, {PB_1, PWM_6, (SCU_PINIO_FAST | 5)}, {PB_2, PWM_7, (SCU_PINIO_FAST | 5)}, {PB_3, PWM_8, (SCU_PINIO_FAST | 5)}, {PD_0, PWM_15, (SCU_PINIO_FAST | 1)}, {PD_2, PWM_7, (SCU_PINIO_FAST | 1)}, {PD_3, PWM_6, (SCU_PINIO_FAST | 1)}, {PD_4, PWM_8, (SCU_PINIO_FAST | 1)}, {PD_5, PWM_9, (SCU_PINIO_FAST | 1)}, {PD_6, PWM_10, (SCU_PINIO_FAST | 1)}, {PD_9, PWM_13, (SCU_PINIO_FAST | 1)}, {PD_11, PWM_14, (SCU_PINIO_FAST | 6)}, {PD_12, PWM_10, (SCU_PINIO_FAST | 6)}, {PD_13, PWM_13, (SCU_PINIO_FAST | 6)}, {PD_14, PWM_11, (SCU_PINIO_FAST | 6)}, {PD_15, PWM_8, (SCU_PINIO_FAST | 6)}, {PD_16, PWM_12, (SCU_PINIO_FAST | 6)}, {PE_5, PWM_3, (SCU_PINIO_FAST | 1)}, {PE_6, PWM_2, (SCU_PINIO_FAST | 1)}, {PE_7, PWM_5, (SCU_PINIO_FAST | 1)}, {PE_8, PWM_4, (SCU_PINIO_FAST | 1)}, {PE_11, PWM_12, (SCU_PINIO_FAST | 1)}, {PE_12, PWM_11, (SCU_PINIO_FAST | 1)}, {PE_13, PWM_14, (SCU_PINIO_FAST | 1)}, {PE_15, PWM_0, (SCU_PINIO_FAST | 1)}, {PF_9, PWM_1, (SCU_PINIO_FAST | 2)}, {NC, NC, 0} }; static unsigned int pwm_clock_mhz; static void _pwmout_dev_init() { uint32_t i; // set SCT clock and config LPC_CCU1->CLKCCU[CLK_MX_SCT].CFG = (1 << 0); // enable SCT clock in CCU1 LPC_SCT->CONFIG |= PWM_CONFIG; // set config options *PWM_CTRL |= PWM_HALT; // set HALT bit to stop counter // clear counter and set prescaler for desired freq *PWM_CTRL |= PWM_CLEAR | PWM_PRE(SystemCoreClock / PWM_FREQ_BASE - 1); pwm_clock_mhz = PWM_FREQ_BASE / 1000000; // configure SCT events for (i = 0; i < PWM_EVENT_MAX; i++) { *PWM_MATCH(i) = 0; // match register *PWM_MR(i) = 0; // match reload register LPC_SCT->EVENT[i].STATE = 0xFFFFFFFF; // event happens in all states LPC_SCT->EVENT[i].CTRL = (i << 0) | PWM_EVT_MASK; // match condition only } *PWM_LIMIT = (1 << 0) ; // set event 0 as limit // initialize period to 20ms: standard for servos, and fine for e.g. brightness control *PWM_MR0 = PWM_SETCOUNT((uint32_t)(((20 * PWM_FREQ_BASE) / 1000000) * 1000)); // initialize SCT outputs for (i = 0; i < CONFIG_SCT_nOU; i++) { LPC_SCT->OUT[i].SET = (1 << 0); // event 0 will set SCTOUT_xx LPC_SCT->OUT[i].CLR = 0; // set clear event when duty cycle } LPC_SCT->OUTPUT = 0; // default outputs to clear *PWM_CTRL &= ~PWM_HALT; // clear HALT bit to start counter } void pwmout_init(pwmout_t* obj, PinName pin) { // determine the channel PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM); MBED_ASSERT((pwm != (PWMName)NC) && (event < PWM_EVENT_MAX)); // init SCT clock and outputs on first PWM init if (event == 0) { _pwmout_dev_init(); } // init PWM object event++; obj->pwm = pwm; // pwm output obj->mr = event; // index of match reload register // initial duty cycle is 0 pwmout_write(obj, 0); // Wire pinout pinmap_pinout(pin, PinMap_PWM); } void pwmout_free(pwmout_t* obj) { // [TODO] } void pwmout_write(pwmout_t* obj, float value) { if (value < 0.0f) { value = 0.0; } else if (value > 1.0f) { value = 1.0; } // set new pulse width uint32_t us = (uint32_t)((float)PWM_GETCOUNT(*PWM_MR0) * value) * pwm_clock_mhz; pwmout_pulsewidth_us(obj, us); } float pwmout_read(pwmout_t* obj) { float v = (float)PWM_GETCOUNT(*PWM_MR(obj->mr)) / (float)PWM_GETCOUNT(*PWM_MR0); return (v > 1.0f) ? (1.0f) : (v); } void pwmout_period(pwmout_t* obj, float seconds) { pwmout_period_us(obj, seconds * 1000000.0f); } void pwmout_period_ms(pwmout_t* obj, int ms) { pwmout_period_us(obj, ms * 1000); } // Set the PWM period, keeping the duty cycle the same. void pwmout_period_us(pwmout_t* obj, int us) { // calculate number of ticks uint32_t ticks = pwm_clock_mhz * us; uint32_t old_ticks = PWM_GETCOUNT(*PWM_MR0); uint32_t i, v; // set new period *PWM_MR0 = PWM_SETCOUNT(ticks); // Scale pulse widths to preserve the duty ratio for (i = 1; i < PWM_EVENT_MAX; i++) { v = PWM_GETCOUNT(*PWM_MR(i)); if (v > 1) { v = (v * ticks) / old_ticks; *PWM_MR(i) = PWM_SETCOUNT(v); } } } void pwmout_pulsewidth(pwmout_t* obj, float seconds) { pwmout_pulsewidth_us(obj, seconds * 1000000.0f); } void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) { pwmout_pulsewidth_us(obj, ms * 1000); } void pwmout_pulsewidth_us(pwmout_t* obj, int us) { // calculate number of ticks uint32_t v = pwm_clock_mhz * us; //MBED_ASSERT(PWM_GETCOUNT(*PWM_MR0) >= v); if (v > 0) { // set new match register value and enable SCT output *PWM_MR(obj->mr) = PWM_SETCOUNT(v); LPC_SCT->OUT[obj->pwm].CLR = (1 << obj->mr); // on event will clear PWM_XX } else { // set match to zero and disable SCT output *PWM_MR(obj->mr) = 0; LPC_SCT->OUT[obj->pwm].CLR = 0; } }