wt is the difference bw PWM driver and PWM Library example

RE: wt is the difference bw PWM driver and PWM Library example

saiteja — Wed, 15 Mar 2017 10:19:40 GMT

The motor is keep on running without GPIO i/p connection also.

RE: wt is the difference bw PWM driver and PWM Library example

Jørn — Wed, 15 Mar 2017 10:16:40 GMT

Voltage over the capacitor will be 5V as it is connected directly to VCC3, I assume this is a decoupling capacitor. If you have 0 volts over the motor I suspect the transistor never starts conducting properly as you would then have 5 V on both sides of the motor.

RE: wt is the difference bw PWM driver and PWM Library example

saiteja — Wed, 15 Mar 2017 08:05:30 GMT

hi, if i observe the voltage drop through motor i am getting 0. and the voltage drop through the capacitor is 5v. please observe my circuit in above Q. here i am applying 5v to VCC3. and connected GPIO to resistor. GPIO is giveing Puse waveform of max 2.8 volts. still i am not able to run motor. plz help me from this.

RE: wt is the difference bw PWM driver and PWM Library example

Jørn — Tue, 14 Mar 2017 13:44:43 GMT

The maximum output voltage from GPIO on the nRF52 series is VDD, so your maximum output voltage is dependent on the supply voltage. You need to make sure the output voltage from your low pass filter is within the specifications of your motor (2.7-3.3 V DC), considering your maximum PWM voltage is 2.8 V you may need to amplify the output of the filter.

RE: wt is the difference bw PWM driver and PWM Library example

saiteja — Tue, 14 Mar 2017 13:23:58 GMT

hi, i have connected LPF but the motor not vibrating. i am drived GPIO pin as PWM. if i observe the GPIO pin voltage its varying from 2.8 volts to 0 volts.

RE: wt is the difference bw PWM driver and PWM Library example

Jørn — Wed, 08 Mar 2017 12:47:17 GMT

You can use either the PWM driver with its dedicated hardware or you can use the PWM library.

In the PWM library example you can change the frequency of the PWM signal by uninitializing the PWM instance, changing the .period_us value in pwm1_cfg, and then initializing the PWM instance again.

The while loops in the example are used to change how quickly the leds ramp up and down by changing the duty cycle of the PWM signal. These are not needed if you only intend to change the frequency.

To only send for a few seconds you can use a timer, and in the callback function you can stop the PWM and change its frequency if needed.

What voltage do you have on the output of your LPF? According to the datasheet of the C0820B006F it has an operating voltage requirement of 2.7 – 3.3 V DC.

Best regards

Jørn Frøysa

RE: wt is the difference bw PWM driver and PWM Library example

saiteja — Mon, 06 Mar 2017 17:52:53 GMT

and also when i drive a GPIOT pin using PWM library (the code shown above Edit:- ) i was stuck in while loop that means it keep on giving PWM signal. with max voltage varying between 2.5v to 0v. the problem is 1)i need to drive GPIOT only for few seconds. 2)when i connect vibrator( C0820B006F) through MOSFET LPF it is unable to vibrate.

RE: wt is the difference bw PWM driver and PWM Library example

saiteja — Mon, 06 Mar 2017 17:44:11 GMT

hey thank you for your time, as per my requirement i want to drive a vibrator for few seconds with defferent frequencies through a GPIOTE so that i need to use PWM Library right?

RE: wt is the difference bw PWM driver and PWM Library example

Jørn — Mon, 06 Mar 2017 15:24:00 GMT

Hello saiteja

The PWM driver and library provide two ways of generating a PWM signal on the nRF52. The PWM driver uses dedicated hardware to generate the signal, while the PWM library uses GPIOTE, PPI and timers in combination.

For more information on the two and their properties please see the following links to the infocenter

PWM driver (dedicated hardware):

infocenter.nordicsemi.com/index.jsp

PWM library (GPIOTE, PPI and timers):

infocenter.nordicsemi.com/.../lib_pwm.html

You can find links to descriptions of the examples you mentioned (pwm_driver and pwm_library in the examples->peripheral folder) on the pages of the infocenter links above.

Best regards

Jørn Frøysa