Capture Qei position and send to usb

the Leaflet (for Thorlabs Z825) says: ....

that does not change that
When the encoder stop exactly over a border in the optical disc a minuscule vibration ........

the Leaflet (for Thorlabs Z825) says: ....

that does not change that
When the encoder stop exactly over a border in the optical disc a minuscule vibration ........

I want to run the motor for 2 seconds and record the data during first 1.9 secs. does it affected by this vibration? I just want to plot the diagram in PC. I can ignore first and last pulses in my observations (due to my application). so does such high frequency pulses occurs during other middle counts?
the moutor is mounted on an active vibration isolated table. does vibration from motor also causes high freqency pulses??

thanks

I want to run the motor for 2 seconds and record the data during first 1.9 secs. does it affected by this vibration?
not likely, the main 'vibration pulsing' happen at stop and start

I can ignore first and last pulses in my observations
then all you get is constant speed, why 'plot' that

Erik

thanks
no its not constant. there is a transient state between on & off. I want to plot step response!
do you have any idea about my first question at the top the page?

Best regards

> I want to draw graphs of position of 2-phased QEI versus time.

As of QEI unit of LPC17xx, an ENCLK_Int interrupt occurs at the every transition of the encoder. In this ISR, your firmware reads out a timer value, which runs freely, to know the interval of the every transition. Cortex-M3 NVIC has fixed interrupt latency of 12 cycle. You may get exact interval with this method.

Erik,

> When the encoder stop exactly over a border in the optical disc a minuscule vibration (which is there in any mechanical desogn) will cause a higher frequency of pulses.

Such a noise is filtered by,
1) R/C (or L/C) filter at the input pins of the QEI unit.
And
2) The integrated digital filter of the LPC17xx QEI unit.

Tsuneo

thanks:

Such a noise is filtered by,
1) R/C (or L/C) filter at the input pins of the QEI unit.
And
2) The integrated digital filter of the LPC17xx QEI unit.
Is it embedded in the IC or Should I do ?
LPC_QEI->FILTER =???(What should i put??)

As of QEI unit of LPC17xx, an ENCLK_Int interrupt occurs at the every transition of the encoder....
I have written below codes to send the data to usb using usbhost lite.
FILE_Open, FILE_Write & FILE_Close belong to USBHostlite part:

void qei_main(){
        //Basic Configuration:
        LPC_SC->PCONP |= (1<<18);
        LPC_SC->PCLKSEL1  |= (0x01);
        //configuration for the pins:
        LPC_PINCON->PINSEL3 |=((1<<8)|(1<<14)|(1<<16));//PH A&B & index
        LPC_QEI->QEICONF =(1<<2);//PhA and PhB function as quadrature encoder inputs.(4x)
        LPC_QEI->QEICON = 0x02;//Control register: Reset position counter on index.(RESPI)
        LPC_QEI->INXCMP = 0x00;//QEI Index Compare register                                                                                                           LPC_QEI->QEILOAD = 0x00;//QEI Timer Reload register
        LPC_QEI->QEICLR = 0xFFFFFFFF;
        LPC_QEI->QEIIEC = 0xFFFFFFFF;
        LPC_QEI->QEIIES = 0x00000020;//enable ENCLK_EN
}
NVIC_EnableIRQ(QEI_IRQn);               /*enable the interrupt*/
NVIC_SetPriority (USB_IRQn, 1);         /*2nd priority--is it correct??*/

void QEI_IRQHandler(void){
        USB_INT32S  fdw;
        fdw = FILE_Open(FILENAME_W, RDWR);
        if (fdw>0) {
                *UserBuffer=LPC_QEI->QEITIME;
                FILE_Write(fdw,UserBuffer,4);
                FILE_Close(fdw);
        }else{
                return;
        }
        LPC_QEI->QEICLR = 0xFFFFFFFF;   // clear all interrupts
}

Is it correct set priority of USB to 0 and QEI to 1??

kind regards

> LPC_QEI->FILTER =???(What should i put??

The time constant of the passive input RC (LC) filter is determined by the PCLK frequency of QEI.
It's much less than (1/8 - 1/16) of PCLK
QEI FILTER register holds a minimum expected interval of encoder transition, counted in PCLK scale.

> Is it correct set priority of USB to 0 and QEI to 1??

QEI should have the highest priority (0), and USB is assigned to lower priority than QEI.

> I have written below codes to send the data to usb using usbhost lite.

FILE_Open, FILE_Write and FILE_Close are too slow to run in the QEI ISR.
Also, it is efficient to write data of sector size at a time.

In the QEI ISR, the timer value is written to a buffer of 1024 bytes.
When the buffer holds 512 bytes (sector size) or more, one sector of data is written to the USB drive.

Tsuneo

>The time constant of the passive input RC (LC) filter is determined by the PCLK frequency of QEI.
It's much less than (1/8 - 1/16) of PCLK

So, if i want to filter pulses less than 2us, what should i write?(clk=100mhz)
LPC_QEI->FILTER =0xc8; /*200*/
Is it correct?

>When the buffer holds 512 bytes (sector size) or more, one sector of data is written to the USB drive.

Oh, I am a beginner!
I don't know how to access to the buffer. How can i get access to this Buffer?
what should i write instead of *UserBuffer=LPC_QEI->QEITIME; ??
can you help me with the codes?
thanks

>When the buffer holds 512 bytes (sector size) or more, one sector of data is written to the USB drive.

Thanks Dr Tsuneo Chinzei

But how can i detect that number of bytes written in QEITIME is 512?
And how to Empty the buffer after writing data?

An other Question: Is it correct to write LPC_QEI->FILTER =0xc8; /*200*/ to filter less than 2us when clock is 100mhz?

Best Regards?

I still haven't got answered my previous questions!
I don't know how to get access to the buffer that included timer(QEITIME) values?

another question:
what is the practical difference between set register & enable register(QEISET & QEIIES)? Can you give me an example please?

Amir
hejazi1365[at]gmail[dot]com
Best regards

Hi Dear Erik
It seems that Tsuneo rarely comes here!
due to low rate of USB functions, i must buffer data and send them in batch. And in the end, i should reset the timer.
so how can i buffer the data? should i use an auxiliary register?
how can i detect that number of bytes written in QEITIME(or auxilary Buffer) is 512?
should i pend the interrupt to send the data(buffer) to USB? cause the usb functions are too slow?

Amir
hejazi1365[at]gmail[dot]com
Best regards

I got really disappointed!!
Any body couldn't help me with the buffer?

thanks
Amir
hejazi1365[at]gmail[dot]com

I got really disappointed!!
Any body couldn't help me with the buffer?

not trying to 'disappoint' you but I can't simply because I have never worked with this specific issue (have no idea what QEITIME is)
how can i detect that number of bytes written in QEITIME(or auxilary Buffer) is 512?
for the usual buffer which is written by address[index] 'index', of course will hol;d the count.

Erik

Maybe you would care to expand why you feel "really disappointed".

It isn't like you are paying to get support from this web forum.

The only way other Keil users can help you is by spending their time retrieving the available information and read it. The big question is why other people should invest their own, private, time to do that when they don't have any incentive to do so. That time could instead be spent listening to music, walking the dog or maybe earn $$$ by developing applications.

You, on the other hand, should have specific incentives to spend time with the available sample source code, application notes and processor user manual.

>Aren't you a funny guy?

>Maybe you would care to expand why you feel "really disappointed".

I don't care you are an active user or a KEIL Employee. but is it your amusement to visit this forum to write such sentences?

Some people usually share their information & knowledge through forum and some other ask (or even beg) other people to help them.
I didn't forced Mr Tsuneo & Mr Erik to answer me! Both of them kindly answered some of my questions. And speaking about "disappointing" won't oblige them to answer and I think it does not contain any insults.

Amir
Hejazi.1365@gmail.com

What amusement do you find in the sentence "Maybe you would care to expand why you feel 'really disappointed'"?

Did you _really_ read what I wrote?

"Some people usually share their information & knowledge through forum and some other ask (or even beg) other people to help them."

Share information requires that the helper already know the answer. If no one who reads your question knows the answer, then no one will be able to share that answer too, unless they invest own time to figure out the answer. And here is where you _do_ have to care about people just being other users of the Keil tools like your self, or if this is a payed support service where people are payed to supply help.

By the way - all your posting of email addresses implies that you want answers sent directly to you instead of having the answers posted on this forum. Private answers do have the big disadvantage that they can't be picked up by Google. So they would not help anyone else.