mirror of
https://github.com/DCC-EX/CommandStation-EX.git
synced 2024-11-26 17:46:14 +01:00
Allow frequency of PWM to be set for PCA9685 drivers.
It's a parameter on the create() call, e.g. PCA9685::create(vpin, npins, address, frequency);
This commit is contained in:
Neil McKechnie
parent
3292c93192
commit
21c82b37b0
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@ -326,6 +326,7 @@ private:
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// structures for setting up non-blocking writes to servo controller
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I2CRB requestBlock;
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uint8_t outputBuffer[5];
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uint8_t prescaler; // clock prescaler for setting PWM frequency
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};
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/////////////////////////////////////////////////////////////////////////////////////////////////////
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@ -31,22 +31,21 @@ static const byte MODE1_AI=0x20; /**< Auto-Increment enabled */
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static const byte MODE1_RESTART=0x80; /**< Restart enabled */
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static const float FREQUENCY_OSCILLATOR=25000000.0; /** Accurate enough for our purposes */
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static const uint8_t PRESCALE_50HZ = (uint8_t)(((FREQUENCY_OSCILLATOR / (50.0 * 4096.0)) + 0.5) - 1);
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static const uint32_t MAX_I2C_SPEED = 1000000L; // PCA9685 rated up to 1MHz I2C clock speed
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// Predeclare helper function
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static void writeRegister(byte address, byte reg, byte value);
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// Create device driver instance.
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void PCA9685::create(VPIN firstVpin, int nPins, I2CAddress i2cAddress) {
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if (checkNoOverlap(firstVpin, nPins,i2cAddress)) new PCA9685(firstVpin, nPins, i2cAddress);
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void PCA9685::create(VPIN firstVpin, int nPins, I2CAddress i2cAddress, uint16_t frequency) {
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if (checkNoOverlap(firstVpin, nPins,i2cAddress)) new PCA9685(firstVpin, nPins, i2cAddress, frequency);
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}
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// Configure a port on the PCA9685.
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bool PCA9685::_configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) {
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if (configType != CONFIGURE_SERVO) return false;
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if (paramCount != 5) return false;
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#ifdef DIAG_IO
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#if DIAG_IO >= 3
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DIAG(F("PCA9685 Configure VPIN:%d Apos:%d Ipos:%d Profile:%d Duration:%d state:%d"),
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vpin, params[0], params[1], params[2], params[3], params[4]);
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#endif
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@ -73,10 +72,14 @@ bool PCA9685::_configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, i
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}
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// Constructor
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PCA9685::PCA9685(VPIN firstVpin, int nPins, I2CAddress i2cAddress) {
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PCA9685::PCA9685(VPIN firstVpin, int nPins, I2CAddress i2cAddress, uint16_t frequency) {
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_firstVpin = firstVpin;
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_nPins = (nPins > 16) ? 16 : nPins;
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_I2CAddress = i2cAddress;
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// Calculate prescaler value for PWM clock
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if (frequency > 1526) frequency = 1526;
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else if (frequency < 24) frequency = 24;
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prescaler = FREQUENCY_OSCILLATOR / 4096 / frequency;
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// To save RAM, space for servo configuration is not allocated unless a pin is used.
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// Initialise the pointers to NULL.
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for (int i=0; i<_nPins; i++)
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@ -98,7 +101,7 @@ void PCA9685::_begin() {
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// Initialise I/O module here.
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if (I2CManager.exists(_I2CAddress)) {
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writeRegister(_I2CAddress, PCA9685_MODE1, MODE1_SLEEP | MODE1_AI);
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writeRegister(_I2CAddress, PCA9685_PRESCALE, PRESCALE_50HZ); // 50Hz clock, 20ms pulse period.
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writeRegister(_I2CAddress, PCA9685_PRESCALE, prescaler);
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writeRegister(_I2CAddress, PCA9685_MODE1, MODE1_AI);
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writeRegister(_I2CAddress, PCA9685_MODE1, MODE1_RESTART | MODE1_AI);
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// In theory, we should wait 500us before sending any other commands to each device, to allow
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@ -114,7 +117,7 @@ void PCA9685::_begin() {
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// Device-specific write function, invoked from IODevice::write().
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// For this function, the configured profile is used.
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void PCA9685::_write(VPIN vpin, int value) {
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#ifdef DIAG_IO
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#if DIAG_IO >= 3
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DIAG(F("PCA9685 Write Vpin:%d Value:%d"), vpin, value);
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#endif
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int pin = vpin - _firstVpin;
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@ -141,7 +144,7 @@ void PCA9685::_write(VPIN vpin, int value) {
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// 4 (Bounce) Servo 'bounces' at extremes.
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//
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void PCA9685::_writeAnalogue(VPIN vpin, int value, uint8_t profile, uint16_t duration) {
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#ifdef DIAG_IO
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#if DIAG_IO >= 3
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DIAG(F("PCA9685 WriteAnalogue Vpin:%d Value:%d Profile:%d Duration:%d %S"),
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vpin, value, profile, duration, _deviceState == DEVSTATE_FAILED?F("DEVSTATE_FAILED"):F(""));
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#endif
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@ -23,6 +23,22 @@
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* commands the device to set the PWM mark-to-period ratio accordingly.
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* The call to IODevice::writeAnalogue(vpin, value) specifies the
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* desired value in the range 0-4095 (0=0% and 4095=100%).
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*
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* This driver can be used for simple servo control by writing values between
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* about 102 and 450 (extremes of movement for 9g micro servos) or 150 to 250
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* for a more restricted range (corresponding to 1.5ms to 2.5ms pulse length).
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* A value of zero will switch off the servo. To create the device, use
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* the following syntax:
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*
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* PCA9685_basic::create(vpin, npins, i2caddress);
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*
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* For LED control, a value of 0 is fully off, and 4095 is fully on. It is
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* recommended, to reduce flicker of LEDs, that the frequency be configured
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* to a value higher than the default of 50Hz. To do this, create the device
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* as follows, for a frequency of 200Hz.:
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*
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* PCA9685_basic::create(vpin, npins, i2caddress, 200);
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*
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*/
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#ifndef PCA9685_BASIC_H
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@ -39,34 +55,38 @@
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class PCA9685pwm : public IODevice {
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public:
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// Create device driver instance.
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static void create(VPIN firstVpin, int nPins, I2CAddress i2cAddress) {
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if (checkNoOverlap(firstVpin, nPins, i2cAddress)) new PCA9685pwm(firstVpin, nPins, i2cAddress);
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static void create(VPIN firstVpin, int nPins, I2CAddress i2cAddress, uint16_t frequency = 50) {
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if (checkNoOverlap(firstVpin, nPins, i2cAddress)) new PCA9685pwm(firstVpin, nPins, i2cAddress, frequency);
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}
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private:
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// structures for setting up non-blocking writes to servo controller
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// structures for setting up non-blocking writes to PWM controller
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I2CRB requestBlock;
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uint8_t outputBuffer[5];
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uint16_t prescaler;
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// REGISTER ADDRESSES
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const uint8_t PCA9685_MODE1=0x00; // Mode Register
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const uint8_t PCA9685_FIRST_SERVO=0x06; /** low uint8_t first servo register ON*/
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const uint8_t PCA9685_FIRST_SERVO=0x06; /** low uint8_t first PWM register ON*/
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const uint8_t PCA9685_PRESCALE=0xFE; /** Prescale register for PWM output frequency */
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// MODE1 bits
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const uint8_t MODE1_SLEEP=0x10; /**< Low power mode. Oscillator off */
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const uint8_t MODE1_AI=0x20; /**< Auto-Increment enabled */
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const uint8_t MODE1_RESTART=0x80; /**< Restart enabled */
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const float FREQUENCY_OSCILLATOR=25000000.0; /** Accurate enough for our purposes */
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const uint32_t FREQUENCY_OSCILLATOR=25000000; /** Accurate enough for our purposes */
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const uint8_t PRESCALE_50HZ = (uint8_t)(((FREQUENCY_OSCILLATOR / (50.0 * 4096.0)) + 0.5) - 1);
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const uint32_t MAX_I2C_SPEED = 1000000L; // PCA9685 rated up to 1MHz I2C clock speed
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// Constructor
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PCA9685pwm(VPIN firstVpin, int nPins, I2CAddress i2cAddress) {
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PCA9685pwm(VPIN firstVpin, int nPins, I2CAddress i2cAddress, uint16_t frequency) {
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_firstVpin = firstVpin;
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_nPins = (nPins>16) ? 16 : nPins;
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_I2CAddress = i2cAddress;
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if (frequency > 1526) frequency = 1526;
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else if (frequency < 24) frequency = 24;
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prescaler = FREQUENCY_OSCILLATOR / 4096 / frequency;
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addDevice(this);
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// Initialise structure used for setting pulse rate
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@ -83,7 +103,7 @@ private:
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// Initialise I/O module here.
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if (I2CManager.exists(_I2CAddress)) {
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writeRegister(_I2CAddress, PCA9685_MODE1, MODE1_SLEEP | MODE1_AI);
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writeRegister(_I2CAddress, PCA9685_PRESCALE, PRESCALE_50HZ); // 50Hz clock, 20ms pulse period.
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writeRegister(_I2CAddress, PCA9685_PRESCALE, prescaler);
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writeRegister(_I2CAddress, PCA9685_MODE1, MODE1_AI);
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writeRegister(_I2CAddress, PCA9685_MODE1, MODE1_RESTART | MODE1_AI);
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// In theory, we should wait 500us before sending any other commands to each device, to allow
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@ -100,7 +120,7 @@ private:
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//
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void _writeAnalogue(VPIN vpin, int value, uint8_t param1, uint16_t param2) override {
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(void)param1; (void)param2; // suppress compiler warning
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#ifdef DIAG_IO
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#if DIAG_IO >= 3
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DIAG(F("PCA9685pwm WriteAnalogue Vpin:%d Value:%d %S"),
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vpin, value, _deviceState == DEVSTATE_FAILED?F("DEVSTATE_FAILED"):F(""));
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#endif
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@ -121,7 +141,7 @@ private:
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// writeDevice (helper function) takes a pin in range 0 to _nPins-1 within the device, and a value
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// between 0 and 4095 for the PWM mark-to-period ratio, with 4095 being 100%.
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void writeDevice(uint8_t pin, int value) {
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#ifdef DIAG_IO
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#if DIAG_IO >= 3
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DIAG(F("PCA9685pwm I2C:%s WriteDevice Pin:%d Value:%d"), _I2CAddress.toString(), pin, value);
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#endif
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// Wait for previous request to complete
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