Use PWM D/A convertor

Started by haoyeshen in Freescale DSPs14 years ago 3 replies

I am trying to develop a small application for speech signal by using dsp56f801. One of the problem i am having is how to use PWM...

I am trying to develop a small application for speech signal by using dsp56f801. One of the problem i am having is how to use PWM as a D/A convertor. My understanding of how the PWM work is as follow: - PWM in dsp56f801 has 15 bit resolution - PWM uses a counter to deci


56803 PWM duty cycle sweep speed

Started by Corey, Rick in Freescale DSPs15 years ago 4 replies

Hi We are presently trying to use the DSP56F803 PWM (channel 4) as a simple independent PWM output. We are sweeping the output...

Hi We are presently trying to use the DSP56F803 PWM (channel 4) as a simple independent PWM output. We are sweeping the output duty cycle from 0% to 100% and therefore, updating and reloading the PWM timer on every timeout interrupt of the PWM. When we then observ


fastest PWM clock source in 56F805

Started by steveroverdrive in Freescale DSPs13 years ago 1 reply

It appears that the only clock source for the PWM unit is the IPBUS, which is always 1/2 the chip operating frequency (section 11.5.2). My ...

It appears that the only clock source for the PWM unit is the IPBUS, which is always 1/2 the chip operating frequency (section 11.5.2). My chip is running at 80 MHz, so I get a 40MHz clock at the PWM unit. I need a faster PWM clock speed, for smaller pulse-width deltas at high pwm rates. Is there any way in the 56F805 to clock the PWM unit at the full chip operat


DSP56F805 Synchronous sampling twice per PWM period

Started by Mstr in Freescale DSPs12 years ago 1 reply

Hello, I've got a sensorless BLDC motor control application on a DSP56F805. I'm sampling the entire ADC bank, including phase currents and...

Hello, I've got a sensorless BLDC motor control application on a DSP56F805. I'm sampling the entire ADC bank, including phase currents and voltages, at the trough of the PWM carrier (center aligned PWM) in order to measure average current. I'm using a minimum-ripple PWM scheme in which the top switch turns off and the current circulates around GND for part of the PWM cycle. For better ...


PWM vs PWMMC

Started by Ko Ihara in Freescale DSPs13 years ago 1 reply

I'm using 56F805 to control a number of DC controllers. The DSP is hooked up to a separate H-bridge, which receives two digital signals for...

I'm using 56F805 to control a number of DC controllers. The DSP is hooked up to a separate H-bridge, which receives two digital signals for direction, and one PWM for current control (for 1 motor). Is there an advantage to using PWMMC over the regular PWM bean? All the functionality seems to be in PWM already, so what's the advantage of PWMMC?


DSP56F807: Synchronization of on chip ADC to PWM

Started by wjschint in Freescale DSPs16 years ago

I'm trying to synchronize the ADC's (both A and B) to the PWM, as described in Mot. app. note AN1933/D, section 5.2. I am using ...

I'm trying to synchronize the ADC's (both A and B) to the PWM, as described in Mot. app. note AN1933/D, section 5.2. I am using center-aligned PWM technique (Fig. 5-4 in app note). I want to have a sample at a specific location in each PWM half-cycle. I have two questions related to


How to reset PWM Counter Register on a 56F805?

Started by Bruno Tremblay in Freescale DSPs16 years ago

Hi, I want to know when PWMEN is put to 0 does that reset the PWM Counter Register? If not, can someone have an idea on how I...

Hi, I want to know when PWMEN is put to 0 does that reset the PWM Counter Register? If not, can someone have an idea on how I can reset or put a value in the PWM Counter Register (read only) without changing the other registers of the PWM? The reason I want to do this is that


Application brief BR1544/D

Started by Roelof Oelofsen in Freescale DSPs17 years ago 2 replies

Hi all, In the motorola app. brief to design a class D amplifier, the author states that to work out the PWM value register,...

Hi all, In the motorola app. brief to design a class D amplifier, the author states that to work out the PWM value register, the following formula applies: PWM Value = (Input Data Sample) x (PWM Modulus) However, in the 56f80x user's manual, it is stated th


PWM problem

Started by in Freescale DSPs15 years ago 2 replies

hi! i am trying to learn pwm module of 56f8323 in my 56f8300 demo board. i have used pwm init. bean. here the code which generated...

hi! i am trying to learn pwm module of 56f8323 in my 56f8300 demo board. i have used pwm init. bean. here the code which generated by PE: setReg( PWMA_PMFCTL, 0x0000); setReg( PWMA_PWMCM, 0x02EE); setReg( PWMA_PWMVAL0, 0x02BC); setReg( PWMA_PWM


phase-shift pwm control with DSP

Started by Robert Imhoff in Freescale DSPs15 years ago 7 replies

Hello I would like to inquire if anyone has attempted to implement a phase-shift PWM control for a full-bridge DC-DC converter...

Hello I would like to inquire if anyone has attempted to implement a phase-shift PWM control for a full-bridge DC-DC converter with the built-in PWM module of the 56800E DSPs, or is that too complicated and one should use a separate dedicated chip? The idea is to


ADC sync with PWM

Started by Bruno Tremblay in Freescale DSPs16 years ago 1 reply

Hi, I'm trying to use the synchronization feature of the ADC with PWM on a DSP56F805 and I don't find user manual clear on this...

Hi, I'm trying to use the synchronization feature of the ADC with PWM on a DSP56F805 and I don't find user manual clear on this subject. Form what I can understand, the PWM outputs a synchronization pulse connected as an input to the quad timer module C, input of TC2 at each r


DSP56F807 PWM Automatic Fault Clearing

Started by frankbertling in Freescale DSPs16 years ago

Dear All, In contradiction to the behaviour described in the User?s Manual (DSP56F801-7UM/D - Rev. 3.0, Chapter 11.5.8.2), we...

Dear All, In contradiction to the behaviour described in the User?s Manual (DSP56F801-7UM/D - Rev. 3.0, Chapter 11.5.8.2), we observe PWM outputs being re-enabled within a PWM cycle as soon as the Fault input (configured for automatic fault clearing) returns to zero.


DSP56F80x Pwm port directly drive Leds or optocoupler?

Started by hao yuan in Freescale DSPs17 years ago

Hi everybody, May I use the pwm port with resistors drive the leds and/or optocouplers directly? I mean without any buffers...

Hi everybody, May I use the pwm port with resistors drive the leds and/or optocouplers directly? I mean without any buffers as 74ls06 or 74ls07. The max current of pwm is 20ma and we can confine the currents 10ma. Is that ok? or will it do any harm to the whole DSP


Calculation for PWM using 827

Started by Nitin Madhukar Yewale in Freescale DSPs17 years ago 1 reply

Hi, I am using 827 processor for my application. Core freq is 80Mhz so peripheral freq is 40Mhz. I want to generate PWM (under...

Hi, I am using 827 processor for my application. Core freq is 80Mhz so peripheral freq is 40Mhz. I want to generate PWM (under variable freq PWM mode) of 10 Hz frq and 1.5 mili seconds [Pulse width]. Here are the calculation for the same. If I use prescaler of 64 t


Increase resolution for a high frequency PWM on DSP56803

Started by Bruno Tremblay in Freescale DSPs16 years ago 1 reply

Hi, Is it possible to increase the resolution for the PWM output when using it at a frequency of about 100kHz? I looked at the...

Hi, Is it possible to increase the resolution for the PWM output when using it at a frequency of about 100kHz? I looked at the chapter 11 of the user's manual and I didn't found my answer. Can I put an external fast clock on an input to speedup timer the PWM timer/counter.


Reloading of on off time for quad timer for PWM mode.

Started by Nitin Madhukar Yewale in Freescale DSPs16 years ago

Hi, I have an application for 56F827 processor, in which I am using Quad timer in PWM mode. On and off time for PWM mode of...

Hi, I have an application for 56F827 processor, in which I am using Quad timer in PWM mode. On and off time for PWM mode of Quad timer will change according to the input (Dynamically). I have initialized quad timer as follows:- **********************


PWM signal from DSP EVM

Started by millindala in Freescale DSPs17 years ago 1 reply

Hi, I am using a DSP56805EVM to generate the PWM signals for a three- phase inverter. I have created a C program for open-loop...

Hi, I am using a DSP56805EVM to generate the PWM signals for a three- phase inverter. I have created a C program for open-loop V/Hz control of PWM inverter (on the lines of the 3 phase open-loop V/Hz control sample program). In the execution of the program, the 8


56F800DEMO problem with FIR Filter

Started by los_...@yahoo.com.ar in Freescale DSPs12 years ago

Hi, I'm Mateo We are Trying to implement a FIR Filter with a 56F800DEMO Board, outputing the signal via PWM, in audio band. The timer C2 is...

Hi, I'm Mateo We are Trying to implement a FIR Filter with a 56F800DEMO Board, outputing the signal via PWM, in audio band. The timer C2 is set for 8Khz, so the ADC is sampling with that clock base. The PWM is set for reload every cycle and its Frequency is also 8KHz. No matter the taps setting, we always have at the PWM output, some sort of impulse response "drived" by the input signal. ...


PWM

Started by joemccarr in Freescale DSPs17 years ago 1 reply

Hello, Any body got any sample code for setting up the pwm registers and controlling the duty cycle. Have been working on...

Hello, Any body got any sample code for setting up the pwm registers and controlling the duty cycle. Have been working on this for three nights and havent had any success. Thanks Joe


PWM Signals

Started by Fredj Rouatbi in Freescale DSPs16 years ago

I'm looking for C code to control the PWM signal of a 56800 using a sine wave. Fredj

I'm looking for C code to control the PWM signal of a 56800 using a sine wave. Fredj