@@ -42,33 +42,51 @@ ws_ledc::~ws_ledc() {
4242 }
4343}
4444
45+ /* *************************************************************************/
46+ /* !
47+ @brief Checks if a channel has already been allocated for a pin.
48+ @param pin Desired GPIO pin number.
49+ @return The channel number if the pin was successfully or already
50+ attached, otherwise LEDC_CH_ERR.
51+ */
52+ /* *************************************************************************/
53+ uint8_t ws_ledc::_getChannel (uint8_t pin) {
54+ // have we already attached this pin?
55+ for (int i = 0 ; i < MAX_LEDC_PWMS; i++) {
56+ if (_ledcPins[i].pin == pin)
57+ return _ledcPins[i].chan ;
58+ }
59+ return LEDC_CH_ERR;
60+ }
61+
4562/* *************************************************************************/
4663/* !
4764 @brief Allocates a timer + channel for a pin and attaches it.
4865 @param pin Desired GPIO pin number.
49- @param freq Desired LEDC timer frequency, in Hz.
50- @param resolution Desired LEDC timer resolution, in bits.
51- @return The channel number if the pin was successfully attached,
52- otherwise 255.
66+ @param freq Desired timer frequency, in Hz.
67+ @param resolution Desired timer resolution, in bits.
68+ @return The channel number if the pin was successfully or already
69+ attached, otherwise 255.
5370*/
5471/* *************************************************************************/
5572uint8_t ws_ledc::attachPin (uint8_t pin, double freq, uint8_t resolution) {
5673 // have we already attached this pin?
5774 for (int i = 0 ; i < MAX_LEDC_PWMS; i++) {
5875 if (_ledcPins[i].pin == pin)
59- return 255 ;
76+ return _ledcPins[i]. chan ;
6077 }
6178
6279 // allocate chanel
6380 uint8_t chanNum = _allocateChannel (freq, resolution);
64- if (chanNum == 255 )
81+ if (chanNum == LEDC_CH_ERR )
6582 return chanNum;
6683
6784 // attach pin to channel
6885 ledcAttachPin (pin, chanNum);
6986
7087 // allocate pin in pool
7188 _ledcPins[chanNum].pin = pin;
89+ _ledcPins[chanNum].chan = chanNum;
7290
7391 return chanNum;
7492}
@@ -97,25 +115,17 @@ void ws_ledc::detachPin(uint8_t pin) {
97115/* *************************************************************************/
98116/* !
99117 @brief Allocates a channel and timer.
100- @param freq Desired LEDC timer frequency, in Hz.
101- @param resolution Desired LEDC timer resolution, in bits.
118+ @param freq Timer frequency, in Hz.
119+ @param resolution Timer resolution, in bits.
102120 @return The channel number if the timer was successfully initialized,
103121 otherwise 255.
104122*/
105123/* *************************************************************************/
106- uint8_t ws_ledc::_allocateChannel (double freq, uint8_t resolution) {
107- // attempt to allocate an inactive channel
108- uint8_t chanNum = 255 ;
109- for (int i = 0 ; i < MAX_LEDC_PWMS; i++) {
110- if (_ledcPins[i].isActive == false ) {
111- chanNum = i;
112- break ;
113- }
114- }
115-
116- // did we fail to allocate?
117- if (chanNum == 255 )
118- return 255 ;
124+ uint8_t ws_ledc::_allocateChannel (double freq, uint8_t resolution = 16 ) {
125+ // obtain an inactive channel number
126+ uint8_t chanNum = _getInactiveChannel ();
127+ if (chanNum == LEDC_CH_ERR)
128+ return LEDC_CH_ERR; // failed to obtain inactive channel #
119129
120130 // attempt to set up a ledc_timer on the free channel
121131 double rc = ledcSetup (uint8_t (chanNum), freq, resolution);
@@ -129,6 +139,47 @@ uint8_t ws_ledc::_allocateChannel(double freq, uint8_t resolution) {
129139 return chanNum;
130140}
131141
142+ /* *************************************************************************/
143+ /* !
144+ @brief Returns an inactive LEDC channel number.
145+ @returns Inactive channel number if free, otherwise LEDC_CH_ERR.
146+ */
147+ /* *************************************************************************/
148+ uint8_t ws_ledc::_getInactiveChannel () {
149+ for (int ch = 0 ; ch < sizeof (_ledcPins); ch++) {
150+ if (_ledcPins[ch].isActive == false ) {
151+ return ch;
152+ }
153+ }
154+ return LEDC_CH_ERR;
155+ }
156+
157+ /* *************************************************************************/
158+ /* !
159+ @brief Arduino AnalogWrite function, but for ESP32's LEDC.
160+ @param pin The desired pin to write to.
161+ @param value The duty cycle.
162+ */
163+ /* *************************************************************************/
164+ void ws_ledc::analogWrite (uint8_t pin, int value) {
165+ if (value > 255 || value < 0 )
166+ return ;
167+
168+ uint8_t ch;
169+ ch = _getChannel (pin);
170+ if (ch == LEDC_CH_ERR) {
171+ Serial.println (" ERROR: Pin not attached to channel"
172+ return ;
173+ }
174+
175+ // perform duty cycle calculation provided value
176+ // (assumes 12-bit resolution, 2^12)
177+ uint32_t dutyCycle = (4095 / 255 ) * min (value, 255 );
178+
179+ // set the duty cycle of the pin
180+ setDuty (pin, dutyCycle);
181+ }
182+
132183/* *************************************************************************/
133184/* !
134185 @brief Sets the duty cycle of a pin
@@ -150,4 +201,21 @@ void ws_ledc::setDuty(uint8_t pin, uint32_t duty) {
150201 ledcWrite (chan, duty);
151202}
152203
204+ /* *************************************************************************/
205+ /* !
206+ @brief Writes a square wave with a fixed duty cycle and variable
207+ frequency to a pin. Used by piezo buzzers and speakers.
208+ @param pin The desired pin to write to.
209+ @param freq The frequency of the tone, in Hz.
210+ */
211+ /* *************************************************************************/
212+ void ws_ledc::tone (uint8_t pin, uint32_t freq) {
213+ uint8_t ch;
214+ ch = _getChannel (pin);
215+ if (ch == LEDC_CH_ERR) {
216+ // Serial.println("ERROR: Pin not previously attached!");
217+ }
218+ ledcWriteTone (ch, freq);
219+ }
220+
153221#endif // ARDUINO_ARCH_ESP32
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