TMS320C5535: Getting an analogue square signal out from the DSP

Hi Osmar,

The simplest answer is that you can only get boolean values (high/low) from the GPIO. So in order to get analog data you need to use external ADC module in your project.
There is a possible hint about reading analog sensors with GPIO which is described at:
www.raspberrypi-spy.co.uk/.../

BR
Tsvetolin Shulev

Hello Tsvetolin,

This boolean values, can I get them out from the DSP into another device, for example; a PIC microcontroller? Do they oscillate between 0v and 1v or something like that?


Osmar

Mark,

Thank you very much for your contribution. I actually took a look at that example code, but it seems a little bit complicated for me to implement... You see, I am not very good at coding, and what I am trying to do is to add, if possible, a command line to an already existing code I have that is also an example code from TI.

So I was wondering if there was a particular command that would let me create such an output signal in an already existing code.

Is there a way to do that?

Sincerely, Osmar

It is probably easier to connect a wire from a GPIO. And the CSL code can be reduced to a few register writes if you look at the TRM. However, it is easier and preferred for us to support CSL-based software on this e2e forum.

Maybe you can start with the XF pin which is basically a dedicated GPO pin (output only).

On the C5535 eZdsp, the XF pin is connected to LED DS2. You can watch it blink, and then perhaps solder a wire between the LED (or R17) to the PIC input pin.

Something like should make it toggle.

//// top of file
#define DELAY 32000
Uint16 i;
//////

while(1){
asm(" BCLR XF");   //Set XF ouput low

for(i=0; i< DELAY; i++)
{
    asm(" NOP");  //wait some delay
}

asm(" BSET XF");   //Set XF ouput high

for(i=0; i< DELAY; i++)
{
    asm(" NOP");  //wait some delay
}}

If when you build your project, it complains about using algebraic assembly instead of mnemonic assembly, then use these assembly calls instead...

asm("    bit(ST1, #ST1_XF) = #0");   //Set XF ouput low
asm("    bit(ST1, #ST1_XF) = #1");   //Set XF ouput high

Hope this helps,
Mark

Mark,

I am sorry, what do you mean by connecting a wire from a GPIO. Also, what is the TRM?

And to the XF alternative, isn't there a less invasive solution to get that pulse so I don't have to solder anything to the board?

Sincerely, Osmar