forked from nodemcu/nodemcu-firmware
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pwm2.c
253 lines (214 loc) · 8.11 KB
/
pwm2.c
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/*
* Software PWM using soft-interrupt timer1.
* Supports higher frequencies compared to Espressif provided one.
*
* Nikolay Fiykov
*/
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include "mem.h"
#include "pin_map.h"
#include "platform.h"
#include "hw_timer.h"
#include "driver/pwm2.h"
#include "user_interface.h"
#define PWM2_TMR_MAGIC_80MHZ 16
#define PWM2_TMR_MAGIC_160MHZ 32
// module vars, lazy initialized, allocated only if pwm2 is being used
static pwm2_module_data_t *moduleData = NULL;
//############################
// tools
static bool isPinSetup(const pwm2_module_data_t *data, const uint8_t pin) {
return data->setupData.pin[pin].pulseResolutions > 0;
}
static uint32_t getCPUTicksPerSec() {
return system_get_cpu_freq() * 1000000;
}
static uint8_t getCpuTimerTicksDivisor() {
return system_get_cpu_freq() == 80 ? PWM2_TMR_MAGIC_80MHZ : PWM2_TMR_MAGIC_160MHZ;
}
static uint32_t findGCD(uint32_t n1, uint32_t n2) {
uint32_t n3;
while (n2 != 0) {
n3 = n1;
n1 = n2;
n2 = n3 % n2;
}
return n1;
}
static uint32_t findGreatesCommonDividerForTimerTicks(uint32_t newTimerTicks, uint32_t oldTimerTicks) {
return oldTimerTicks == 0 ? newTimerTicks : findGCD(newTimerTicks, oldTimerTicks);
}
static uint16_t findAllEnabledGpioMask(pwm2_module_data_t *moduleData) {
uint16_t enableGpioMask = 0;
for (int i = 1; i < GPIO_PIN_NUM; i++) {
if (moduleData->setupData.pin[i].pulseResolutions > 0) {
enableGpioMask |= moduleData->interruptData.pin[i].gpioMask;
}
}
return enableGpioMask;
}
static uint32_t findCommonCPUTicksDivisor(pwm2_module_data_t *moduleData) {
uint32_t gcdCPUTicks = 0;
for (int i = 1; i < GPIO_PIN_NUM; i++) {
if (moduleData->setupData.pin[i].pulseResolutions > 0) {
gcdCPUTicks = findGreatesCommonDividerForTimerTicks(moduleData->setupData.pin[i].resolutionCPUTicks, gcdCPUTicks);
}
}
return gcdCPUTicks;
}
static uint32_t cpuToTimerTicks(uint32_t cpuTicks) {
return cpuTicks / getCpuTimerTicksDivisor();
}
static void updatePinResolutionToInterruptsMultiplier(pwm2_pin_setup_t *sPin, uint32_t timerCPUTicks) {
sPin->resolutionInterruptCounterMultiplier = sPin->resolutionCPUTicks / timerCPUTicks;
}
static void updatePinPulseToInterruptsCounter(pwm2_pin_interrupt_t *iPin, pwm2_pin_setup_t *sPin) {
iPin->pulseInterruptCcounter = (sPin->pulseResolutions + 1) * sPin->resolutionInterruptCounterMultiplier;
}
static uint8_t getDutyAdjustment(const uint32_t duty, const uint32_t pulse) {
if (duty == 0) {
return 0;
} else if (duty == pulse) {
return 2;
} else {
return 1;
}
}
static void updatePinOffCounter(pwm2_pin_interrupt_t *iPin, pwm2_pin_setup_t *sPin) {
iPin->offInterruptCounter = (sPin->duty + getDutyAdjustment(sPin->duty, sPin->pulseResolutions)) * sPin->resolutionInterruptCounterMultiplier;
}
static void reCalculateCommonToAllPinsData(pwm2_module_data_t *moduleData) {
moduleData->interruptData.enabledGpioMask = findAllEnabledGpioMask(moduleData);
moduleData->setupData.interruptTimerCPUTicks = findCommonCPUTicksDivisor(moduleData);
moduleData->setupData.interruptTimerTicks = cpuToTimerTicks(moduleData->setupData.interruptTimerCPUTicks);
for (int i = 1; i < GPIO_PIN_NUM; i++) {
if (isPinSetup(moduleData, i)) {
updatePinResolutionToInterruptsMultiplier(&moduleData->setupData.pin[i], moduleData->setupData.interruptTimerCPUTicks);
updatePinPulseToInterruptsCounter(&moduleData->interruptData.pin[i], &moduleData->setupData.pin[i]);
updatePinOffCounter(&moduleData->interruptData.pin[i], &moduleData->setupData.pin[i]);
}
}
}
static uint64_t enduserFreqToCPUTicks(const uint64_t divisableFreq, const uint64_t freqDivisor, const uint64_t resolution) {
return (getCPUTicksPerSec() / (freqDivisor * resolution)) * divisableFreq;
}
static uint16_t getPinGpioMask(uint8_t pin) {
return 1 << GPIO_ID_PIN(pin_num[pin]);
}
static void set_duty(pwm2_module_data_t *moduleData, const uint8_t pin, const uint32_t duty) {
pwm2_pin_setup_t *sPin = &moduleData->setupData.pin[pin];
pwm2_pin_interrupt_t *iPin = &moduleData->interruptData.pin[pin];
sPin->duty = duty;
updatePinOffCounter(iPin, sPin);
}
static void configureAllPinsAsGpioOutput(pwm2_module_data_t *moduleData) {
for (int i = 1; i < GPIO_PIN_NUM; i++) {
if (isPinSetup(moduleData, i)) {
PIN_FUNC_SELECT(pin_mux[i], pin_func[i]); // set pin as gpio
PIN_PULLUP_EN(pin_mux[i]); // set pin pullup on
}
}
}
static void resetPinCounters(pwm2_module_data_t *moduleData) {
for (int i = 1; i < GPIO_PIN_NUM; i++) {
if (isPinSetup(moduleData, i)) {
moduleData->interruptData.pin[i].currentInterruptCounter = 0;
}
}
}
//############################
// interrupt handler related
static inline void computeIsPinOn(pwm2_pin_interrupt_t *pin, uint16_t *maskOn) {
if (pin->currentInterruptCounter == pin->pulseInterruptCcounter) {
pin->currentInterruptCounter = 1;
} else {
pin->currentInterruptCounter++;
}
// ets_printf("curr=%u on=%u\n", pin->currentInterruptCounter, (pin->currentInterruptCounter < pin->offInterruptCounter));
if (pin->currentInterruptCounter < pin->offInterruptCounter) {
*maskOn |= pin->gpioMask;
}
}
static inline bool isPinSetup2(const pwm2_interrupt_handler_data_t *data, const uint8_t pin) {
return data->pin[pin].gpioMask > 0;
}
static inline uint16_t findAllPinOns(pwm2_interrupt_handler_data_t *data) {
uint16_t maskOn = 0;
for (int i = 1; i < GPIO_PIN_NUM; i++) {
if (isPinSetup2(data, i)) {
computeIsPinOn(&data->pin[i], &maskOn);
}
}
return maskOn;
}
static inline void setGpioPins(const uint16_t enabledGpioMask, const register uint16_t maskOn) {
GPIO_REG_WRITE(GPIO_OUT_W1TS_ADDRESS, maskOn);
const register uint16_t maskOff = ~maskOn & enabledGpioMask;
GPIO_REG_WRITE(GPIO_OUT_W1TC_ADDRESS, maskOff);
}
static void ICACHE_RAM_ATTR timerInterruptHandler(os_param_t arg) {
pwm2_interrupt_handler_data_t *data = (pwm2_interrupt_handler_data_t *)arg;
setGpioPins(data->enabledGpioMask, findAllPinOns(data));
}
//############################
// driver's public API
void pwm2_init() {
moduleData = os_malloc(sizeof(pwm2_module_data_t));
memset(moduleData, 0, sizeof(*moduleData));
}
pwm2_module_data_t *pwm2_get_module_data() {
return moduleData;
}
bool pwm2_is_pin_setup(const uint8_t pin) {
return isPinSetup(moduleData, pin);
}
void pwm2_setup_pin(
const uint8_t pin,
const uint32_t divisableFreq,
const uint32_t freqDivisor,
const uint32_t resolution,
const uint32_t initDuty
)
{
moduleData->setupData.pin[pin].pulseResolutions = resolution;
moduleData->setupData.pin[pin].divisableFrequency = divisableFreq;
moduleData->setupData.pin[pin].frequencyDivisor = freqDivisor;
moduleData->setupData.pin[pin].resolutionCPUTicks = enduserFreqToCPUTicks(divisableFreq, freqDivisor, resolution);
moduleData->interruptData.pin[pin].gpioMask = getPinGpioMask(pin);
reCalculateCommonToAllPinsData(moduleData);
set_duty(moduleData, pin, initDuty);
}
void pwm2_release_pin(const uint8_t pin) {
moduleData->setupData.pin[pin].pulseResolutions = 0;
moduleData->interruptData.pin[pin].gpioMask = 0;
}
void pwm2_stop() {
if (!moduleData->setupData.isStarted) {
return;
}
platform_hw_timer_close_exclusive();
GPIO_REG_WRITE(GPIO_ENABLE_W1TC_ADDRESS, moduleData->interruptData.enabledGpioMask); // clear pins of being gpio output
moduleData->setupData.isStarted = false;
}
bool pwm2_start() {
if (moduleData->setupData.isStarted) {
return true;
}
if (!platform_hw_timer_init_exclusive(FRC1_SOURCE, TRUE, timerInterruptHandler, (os_param_t)&moduleData->interruptData, (void (*)(void))NULL)) {
return false;
}
configureAllPinsAsGpioOutput(moduleData);
resetPinCounters(moduleData);
GPIO_REG_WRITE(GPIO_ENABLE_W1TS_ADDRESS, moduleData->interruptData.enabledGpioMask); // set pins as gpio output
moduleData->setupData.isStarted = true;
platform_hw_timer_arm_ticks_exclusive(moduleData->setupData.interruptTimerTicks);
return true;
}
bool pwm2_is_started() {
return moduleData->setupData.isStarted;
}
void pwm2_set_duty(const uint8_t pin, const uint32_t duty) {
set_duty(moduleData, pin, duty);
}