Analogshield and ChipKIT Wi-FIRE

[adralencar]

Does anyone know if AnalogShield will work on the new ChipKit Wi-FIRE (with few modifications) ?

I look inside the library and I saw several " #ifdef __PIC32MX__ "

However the new ChipKit WI-FIRE is " PIC32MZ ", MZ not MX. In other words, without any modification it will not work. However, if the chip is similar, as described in this forum, should be easy.

Thanks

[mwingerson]

Hello adralencar,

I moved your post to a new thread since it is a great question.

The library for the analogShield would be easy to modify for the Wi-FIRE.  Simply, replace all of the

      "#if defined (__PIC32MX__)"

with

      "#if defined (__PIC32MX__) || defined (__PIC32MZXX__)".  

and 

      "#if defined (__PIC32MX__) || defined (__SAM3X8E__)"

with

     "#if defined (__PIC32MX__) || defined (__PIC32MZXX__) || defined (__SAM3X8E__)"

I would definitely pull your changes into the master branch, if you update the library for this.

Tell me how it goes.

Marshall

[adralencar]

Thank you Marshall!

Currently I already made my application to run using Chipkit UNO32 and MAX32 (together with AnalogShield). My next step is to test in a Arduino DUE (I already got one).

My application is in scientific research, so I need as much speed as I can get (to increase time resolution). Thus very soon I will buy the Wi-FIRE to test it.

Do you have any suggestion to speed up the SPI transmission (ChipKit to AnalogShield)? In my application, once I reach 500 Hz wave, or above, I start to see time quantization, probable due the SPI speed. I realize that the AnalogShield do not use the buffered DSPI. Any clue?

This is the piece of my current code, which is inside a loop:

          time=micros()-time0; 
          mag_out = -1 + MED_VALUE*(1+sin(pi2_mil* time));
          #ifdef ANALOG_SHIELD
            analog.write(0,MAG_value_out);
          #endif

 

Thank you,

Adriano

 

[mwingerson]

I haven't been able to test the latest build of the AnalogShield library on the DUE since I do not have a DUE.  I suspect the DUE will not perform as well as the ChipKIT due to the optimizations in place for PIC32.  Regardless, I would like to know the results.

Unfortunately, I never got around to putting the DSPI library into the ChipKIT part of the library.  If I remember right, the SPI module on the PIC32 can run up to 20MHz.  I do not know what the stock speed is in the SPI library.  

I am surprised that you are seeing distortion at that slow of a speed.  I got the library running about as fast as the ADC and DAC can run on a UC32.  Can you post your entire sketch and I might be able to spot something that might cause the slow down?

Marshall