Ken Todotani
mbed library sources
Fork of
mbed-src
by 
mbed official
Diff: targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/pwmout_api.c
- Revision:
- 270:e2babe29baf8
- Parent:
- 251:de9a1e4ffd79
- Child:
- 285:31249416b6f9
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/pwmout_api.c Fri Aug 01 14:45:06 2014 +0100
@@ -0,0 +1,343 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2013 Nordic Semiconductor
+ *
+ * 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.
+ */
+#include "mbed_assert.h"
+#include "pwmout_api.h"
+#include "cmsis.h"
+#include "pinmap.h"
+#include "error.h"
+
+#define NO_PWMS 3
+#define TIMER_PRECISION 4 //4us ticks
+#define TIMER_PRESCALER 6 //4us ticks = 16Mhz/(2**6)
+static const PinMap PinMap_PWM[] = {
+ {p0, PWM_1, 1},
+ {p1, PWM_1, 1},
+ {p2, PWM_1, 1},
+ {p3, PWM_1, 1},
+ {p4, PWM_1, 1},
+ {p5, PWM_1, 1},
+ {p6, PWM_1, 1},
+ {p7, PWM_1, 1},
+ {p8, PWM_1, 1},
+ {p9, PWM_1, 1},
+ {p10, PWM_1, 1},
+ {p11, PWM_1, 1},
+ {p12, PWM_1, 1},
+ {p13, PWM_1, 1},
+ {p14, PWM_1, 1},
+ {p15, PWM_1, 1},
+ {p16, PWM_1, 1},
+ {p17, PWM_1, 1},
+ {p18, PWM_1, 1},
+ {p19, PWM_1, 1},
+ {p20, PWM_1, 1},
+ {p21, PWM_1, 1},
+ {p22, PWM_1, 1},
+ {p23, PWM_1, 1},
+ {p24, PWM_1, 1},
+ {p25, PWM_1, 1},
+ {p28, PWM_1, 1},
+ {p29, PWM_1, 1},
+ {p30, PWM_1, 1},
+ {NC, NC, 0}
+};
+
+static NRF_TIMER_Type *Timers[1] = {
+ NRF_TIMER2
+};
+
+uint16_t PERIOD = 20000/TIMER_PRECISION;//20ms
+uint8_t PWM_taken[NO_PWMS] = {0,0,0};
+uint16_t PULSE_WIDTH[NO_PWMS] = {1,1,1};//set to 1 instead of 0
+uint16_t ACTUAL_PULSE[NO_PWMS] = {0,0,0};
+
+
+/** @brief Function for handling timer 2 peripheral interrupts.
+ */
+ #ifdef __cplusplus
+extern "C" {
+#endif
+void TIMER2_IRQHandler(void)
+{
+ NRF_TIMER2->EVENTS_COMPARE[3] = 0;
+ NRF_TIMER2->CC[3] = PERIOD;
+
+ if(PWM_taken[0]){
+ NRF_TIMER2->CC[0] = PULSE_WIDTH[0];
+ }
+ if(PWM_taken[1]){
+ NRF_TIMER2->CC[1] = PULSE_WIDTH[1];
+ }
+ if(PWM_taken[2]){
+ NRF_TIMER2->CC[2] = PULSE_WIDTH[2];
+ }
+
+ NRF_TIMER2->TASKS_START = 1;
+
+}
+#ifdef __cplusplus
+}
+#endif
+/** @brief Function for initializing the Timer peripherals.
+ */
+void timer_init(uint8_t pwmChoice)
+{
+ NRF_TIMER_Type *timer = Timers[0];
+ timer->TASKS_STOP = 0;
+
+ if(pwmChoice == 0){
+ timer->POWER = 0;
+ timer->POWER = 1;
+ timer->MODE = TIMER_MODE_MODE_Timer;
+ timer->BITMODE = TIMER_BITMODE_BITMODE_16Bit << TIMER_BITMODE_BITMODE_Pos;
+ timer->PRESCALER = TIMER_PRESCALER;
+ timer->CC[3] = PERIOD;
+ }
+
+ timer->CC[pwmChoice] = PULSE_WIDTH[pwmChoice];
+
+ //high priority application interrupt
+ NVIC_SetPriority(TIMER2_IRQn, 1);
+ NVIC_EnableIRQ(TIMER2_IRQn);
+
+ timer->TASKS_START = 0x01;
+}
+/** @brief Function for initializing the GPIO Tasks/Events peripheral.
+ */
+void gpiote_init(PinName pin,uint8_t channel_number)
+{
+ // Connect GPIO input buffers and configure PWM_OUTPUT_PIN_NUMBER as an output.
+ NRF_GPIO->PIN_CNF[pin] = (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos)
+ | (GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos)
+ | (GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos)
+ | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
+ | (GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos);
+ NRF_GPIO->OUTCLR = (1UL << pin);
+ // Configure GPIOTE channel 0 to toggle the PWM pin state
+ // @note Only one GPIOTE task can be connected to an output pin.
+ /* Configure channel to Pin31, not connected to the pin, and configure as a tasks that will set it to proper level */
+ NRF_GPIOTE->CONFIG[channel_number] = (GPIOTE_CONFIG_MODE_Task << GPIOTE_CONFIG_MODE_Pos) |
+ (31UL << GPIOTE_CONFIG_PSEL_Pos) |
+ (GPIOTE_CONFIG_POLARITY_HiToLo << GPIOTE_CONFIG_POLARITY_Pos);
+ /* Three NOPs are required to make sure configuration is written before setting tasks or getting events */
+ __NOP();
+ __NOP();
+ __NOP();
+ /* Launch the task to take the GPIOTE channel output to the desired level */
+ NRF_GPIOTE->TASKS_OUT[channel_number] = 1;
+
+ /* Finally configure the channel as the caller expects. If OUTINIT works, the channel is configured properly.
+ If it does not, the channel output inheritance sets the proper level. */
+ NRF_GPIOTE->CONFIG[channel_number] = (GPIOTE_CONFIG_MODE_Task << GPIOTE_CONFIG_MODE_Pos) |
+ ((uint32_t)pin << GPIOTE_CONFIG_PSEL_Pos) |
+ ((uint32_t)GPIOTE_CONFIG_POLARITY_Toggle << GPIOTE_CONFIG_POLARITY_Pos) |
+ ((uint32_t)GPIOTE_CONFIG_OUTINIT_Low << GPIOTE_CONFIG_OUTINIT_Pos);// ((uint32_t)GPIOTE_CONFIG_OUTINIT_High << GPIOTE_CONFIG_OUTINIT_Pos);//
+
+ /* Three NOPs are required to make sure configuration is written before setting tasks or getting events */
+ __NOP();
+ __NOP();
+ __NOP();
+}
+/** @brief Function for initializing the Programmable Peripheral Interconnect peripheral.
+ */
+static void ppi_init(uint8_t pwm)
+{
+//using ppi channels 0-7 (only 0-7 are available)
+ uint8_t channel_number = 2*pwm;
+ NRF_TIMER_Type *timer = Timers[0];
+
+ // Configure PPI channel 0 to toggle ADVERTISING_LED_PIN_NO on every TIMER1 COMPARE[0] match
+ NRF_PPI->CH[channel_number].TEP = (uint32_t)&NRF_GPIOTE->TASKS_OUT[pwm];
+ NRF_PPI->CH[channel_number+1].TEP = (uint32_t)&NRF_GPIOTE->TASKS_OUT[pwm];
+ NRF_PPI->CH[channel_number].EEP = (uint32_t)&timer->EVENTS_COMPARE[pwm];
+ NRF_PPI->CH[channel_number+1].EEP = (uint32_t)&timer->EVENTS_COMPARE[3];
+
+ // Enable PPI channels.
+ NRF_PPI->CHEN |= (1 << channel_number)
+ | (1 << (channel_number+1));
+}
+
+void setModulation(pwmout_t* obj,uint8_t toggle,uint8_t high)
+{
+ if(high){
+ NRF_GPIOTE->CONFIG[obj->pwm] |= ((uint32_t)GPIOTE_CONFIG_OUTINIT_High << GPIOTE_CONFIG_OUTINIT_Pos);
+ if(toggle){
+ NRF_GPIOTE->CONFIG[obj->pwm] |= (GPIOTE_CONFIG_MODE_Task << GPIOTE_CONFIG_MODE_Pos) |
+ ((uint32_t)GPIOTE_CONFIG_POLARITY_Toggle << GPIOTE_CONFIG_POLARITY_Pos);
+ }
+ else{
+ NRF_GPIOTE->CONFIG[obj->pwm] &= ~((uint32_t)GPIOTE_CONFIG_POLARITY_Toggle << GPIOTE_CONFIG_POLARITY_Pos);
+ NRF_GPIOTE->CONFIG[obj->pwm] |= ((uint32_t)GPIOTE_CONFIG_POLARITY_LoToHi << GPIOTE_CONFIG_POLARITY_Pos);
+ }
+ }
+ else{
+ NRF_GPIOTE->CONFIG[obj->pwm] &= ~((uint32_t)GPIOTE_CONFIG_OUTINIT_High << GPIOTE_CONFIG_OUTINIT_Pos);
+
+ if(toggle){
+ NRF_GPIOTE->CONFIG[obj->pwm] |= (GPIOTE_CONFIG_MODE_Task << GPIOTE_CONFIG_MODE_Pos) |
+ ((uint32_t)GPIOTE_CONFIG_POLARITY_Toggle << GPIOTE_CONFIG_POLARITY_Pos);
+ }
+ else{
+ NRF_GPIOTE->CONFIG[obj->pwm] &= ~((uint32_t)GPIOTE_CONFIG_POLARITY_Toggle << GPIOTE_CONFIG_POLARITY_Pos);
+ NRF_GPIOTE->CONFIG[obj->pwm] |= ((uint32_t)GPIOTE_CONFIG_POLARITY_HiToLo << GPIOTE_CONFIG_POLARITY_Pos);
+ }
+ }
+}
+void pwmout_init(pwmout_t* obj, PinName pin) {
+ // determine the channel
+ uint8_t pwmOutSuccess = 0;
+ PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
+
+ MBED_ASSERT(pwm != (PWMName)NC);
+
+ if(PWM_taken[(uint8_t)pwm]){
+ for(uint8_t i = 1; !pwmOutSuccess && (i<NO_PWMS) ;i++){
+ if(!PWM_taken[i]){
+ pwm = (PWMName)i;
+ PWM_taken[i] = 1;
+ pwmOutSuccess = 1;
+ }
+ }
+ }
+ else{
+ pwmOutSuccess = 1;
+ PWM_taken[(uint8_t)pwm] = 1;
+ }
+
+ if(!pwmOutSuccess){
+ error("PwmOut pin mapping failed. All available PWM channels are in use.");
+ }
+
+ obj->pwm = pwm;
+ obj->pin = pin;
+
+ gpiote_init(pin,(uint8_t)pwm);
+ ppi_init((uint8_t)pwm);
+
+ if(pwm == 0){
+ NRF_POWER->TASKS_CONSTLAT = 1;
+ }
+
+ timer_init((uint8_t)pwm);
+
+ //default to 20ms: standard for servos, and fine for e.g. brightness control
+ pwmout_period_ms(obj, 20);
+ pwmout_write (obj, 0);
+
+}
+
+void pwmout_free(pwmout_t* obj) {
+ // [TODO]
+}
+
+void pwmout_write(pwmout_t* obj, float value) {
+ uint16_t oldPulseWidth;
+
+ NRF_TIMER2->EVENTS_COMPARE[3] = 0;
+ NRF_TIMER2->TASKS_STOP = 1;
+
+ if (value < 0.0f) {
+ value = 0.0;
+ } else if (value > 1.0f) {
+ value = 1.0;
+ }
+
+ oldPulseWidth = ACTUAL_PULSE[obj->pwm];
+ ACTUAL_PULSE[obj->pwm] = PULSE_WIDTH[obj->pwm] = value* PERIOD;
+
+ if(PULSE_WIDTH[obj->pwm] == 0){
+ PULSE_WIDTH[obj->pwm] = 1;
+ setModulation(obj,0,0);
+ }
+ else if(PULSE_WIDTH[obj->pwm] == PERIOD){
+ PULSE_WIDTH[obj->pwm] = PERIOD-1;
+ setModulation(obj,0,1);
+ }
+ else if( (oldPulseWidth == 0) || (oldPulseWidth == PERIOD) ){
+ setModulation(obj,1,oldPulseWidth == PERIOD);
+ }
+
+ NRF_TIMER2->INTENSET = TIMER_INTENSET_COMPARE3_Msk;
+ NRF_TIMER2->SHORTS = TIMER_SHORTS_COMPARE3_CLEAR_Msk | TIMER_SHORTS_COMPARE3_STOP_Msk;
+ NRF_TIMER2->TASKS_START = 1;
+}
+
+float pwmout_read(pwmout_t* obj) {
+ return ((float)PULSE_WIDTH[obj->pwm]/(float)PERIOD);
+}
+
+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) {
+ uint32_t periodInTicks = us/TIMER_PRECISION;
+
+ NRF_TIMER2->EVENTS_COMPARE[3] = 0;
+ NRF_TIMER2->TASKS_STOP = 1;
+
+ if(periodInTicks>((1<<16) -1))
+ {
+ PERIOD = (1<<16 )-1;//131ms
+ }
+ else if(periodInTicks<5){
+ PERIOD = 5;
+ }
+ else{
+ PERIOD =periodInTicks;
+ }
+ NRF_TIMER2->INTENSET = TIMER_INTENSET_COMPARE3_Msk;
+ NRF_TIMER2->SHORTS = TIMER_SHORTS_COMPARE3_CLEAR_Msk | TIMER_SHORTS_COMPARE3_STOP_Msk;
+ NRF_TIMER2->TASKS_START = 1;
+}
+
+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) {
+ uint32_t pulseInTicks = us/TIMER_PRECISION;
+ uint16_t oldPulseWidth = ACTUAL_PULSE[obj->pwm];
+
+ NRF_TIMER2->EVENTS_COMPARE[3] = 0;
+ NRF_TIMER2->TASKS_STOP = 1;
+
+ ACTUAL_PULSE[obj->pwm] = PULSE_WIDTH[obj->pwm] = pulseInTicks;
+
+ if(PULSE_WIDTH[obj->pwm] == 0){
+ PULSE_WIDTH[obj->pwm] = 1;
+ setModulation(obj,0,0);
+ }
+ else if(PULSE_WIDTH[obj->pwm] == PERIOD){
+ PULSE_WIDTH[obj->pwm] = PERIOD-1;
+ setModulation(obj,0,1);
+ }
+ else if( (oldPulseWidth == 0) || (oldPulseWidth == PERIOD) ){
+ setModulation(obj,1,oldPulseWidth == PERIOD);
+ }
+ NRF_TIMER2->INTENSET = TIMER_INTENSET_COMPARE3_Msk;
+ NRF_TIMER2->SHORTS = TIMER_SHORTS_COMPARE3_CLEAR_Msk | TIMER_SHORTS_COMPARE3_STOP_Msk;
+ NRF_TIMER2->TASKS_START = 1;
+}