Audio codec shield with Intel Edison

[youthreewire]

Hello,

Greetings!

After developing a library successfully for the Arduino Due I am planning to extend the same to Intel Edison. So what functionality do we need? Edison does I2C, it can mimic timers and interrupts though actually it does not have them. I think I might have to see how to use an external clock signal to generate interrupts on the edison.

Apart from the external clock interrupt I dont see what problem there could be.Please pour in your suggestions.I will also start a thread in the edison forums.

Thanks

[youthreewire]

So what is the relation between the CLKOUT signal at 11 mhz from the the codec and the ISR at 44 khz. I mean how should the CLKOUT signal and SS pin wave together look like in the oscilloscope?

[guest]

i dont know anything about the edison, but i have a friend i can ask.

as for the clk_out, that should really be at 5.5MHz. its ok if its 11MHz, but the CK/2 bit should be set in the setup registers. the SS output and the clock signal should be synchronized with each other. ie, if you look at them on the scope, they should not move with respect to each other.

[youthreewire]

So when I am using SCL and SDA in I2C what among them is output or input. I think SCL might be output and SDA an input pin. Because in doing I2C communication I need to set the output and input pins. I will first try I2C with BYPASS enable and see if first I2C is working. Then I will code for ISR and timers and then SPI.

[youthreewire]

Just tested I2C, it is working and configuring the codec as needed.I will move onto interrupts,SS and SPI.

[youthreewire]

The question you might want to ask your friend is how do you track at external interrupt signal at 11Mhz/256 (for 44 Khz) and this timing should drive the ISR.

[youthreewire]

You told me in the past that the first pulse of SS should be aligned with the falling edge of SPI Clock. I understood that but now I want to know how should the SS pin wave be aligned to the 11Mhz or 5.5Mhz CLKOUT signal from the codec? Since I am not able to track the CLKOUT in edison I will try to read the moment when it is high and start the timer with respect to the rising edge of the CLKOUT signal. If align them this way at the beginning will it remain aligned for the rest of the time or should we see the RISING edge every time?Please let me know.

[youthreewire]

[guest]

i asked my friend about the edison, and he said it doesnt have any hardware timers that are usable. im not sure how interrupts even work on it. you could put an external counter chip on, but it ultimately may not work. the codecshield is set to work in slave mode, which is not very conducive to most larger platforms. with the edison you can just put a usb sound card on it.

with the master clock and SS signals, i dont think it matters whether its aligned to rising or falling edge, just as long as its consistent.

[youthreewire]

Software emulation of timers and interrupts is there on edison.I am able to get an 8khz interrupt on the edison.Here is the scope shot:

IMG_20150811_144937.jpg (115.75 KiB) Viewed 17662 times