[ts-7000] Generating a 25Khz wave on DIO pins

["yasbug" <>]

Hi all,

I have a 7250 board and am looking to generate a 25Khz square wave on 
a DIO pin.

I am also running debian linux from a USB flash drive. 

I am able to generate a waveform (as seen on an oscilloscope) but 
only at a maximum of 25Hz. I can not achieve a higher frequency. Here 
is a snippit of my C code:

while (1){

     *PBDR = 0x01;
     usleep(20);
     *PBDR = 0x00;
     usleep(20);
}

The usleep() function SHOULD sleep for 20us. However, I can only read 
a 25Hz wave on the oscilloscope meaning that each pulse length is 
20ms. 

A 25Khz wave should have a period of 40useconds with each period 
consisting of a 20us high and a 20us low. For some reason, I cannot 
achieve a frequency over 25Hz on the DIO pins. 

Is there a pulse limitation on the DIO pins? Does the fact that I am 
running Debian off of a USB flash have any affect? Should there be a 
different behavior on the A/D or LCD pins? Any suggestions or ideas?

Thanks,
Yas





 
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