Hifiduino Adapted to Graphic Display
A diyaudio user had adapted the Hifiduino code to use a graphic display. Cool project.
More information about the project here: diyaudio. User “bigpandahk” has put together Ian’s FIFO reclocker with a Buffalo III. On paper this is the “lowest” jitter DAC solution currently available.
A later implementation looks like this:
Another implementation by dimdim looks like this. bigpandahk based his design on dimdim’s code
Even though these screens are all text based, they are already pretty good looking. For those inclined to further modify the code, you can do much more with the graphic display like using icons and even using the touch interface to change DAC parameters and volume.
User DQ828 has this implementation here: [link]
Additional information on the Arduino libraries for the display here and here.
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Hi GLT
Let me say that I have been checking Your site pretty often waiting on impression on Your IAN Re-clocker and I wonder that You did not post anything on it.
Your, as usual, in depth evaluation would be very interesting.
Any info on: “On paper this is the “lowest” jitter DAC solution” ?
Hope all is OK….
Best Regards
Rosendorfer
Thanks for your interest. Right now life is busy, not much time left for hobbies. Based on my own listening experience, I wouldn’t expect to hear any noticeable differences. On paper thought, it is the best way to get rid of jitter and feeding a DAC.
GLT
Do you know if using PWM pins for the Touch pins is mandatory, the have got them on 6 to 2 but I want to move them to 42 to 46?
DQ
Hello,
That is a very interesting question. I wouldn’t think it would make a difference as there are digital devices. But I have not tried the touch feature. If you check my post on the display module http://hifiduino.wordpress.com/2012/04/13/iteadstudio-tft-display-for-arduino/ I have link to the touch controller datasheet. A quick look at the datasheet shows that the connections to the microprocessor are all digital. (Digital meaning it does not require “analog” levels provided by the PWM). Let me know what you find as that would also be helpful to me. Good Luck.
Thanks,
I have tried to wire straight from the mega to the screen for all pins without the shield in between, but have not been able to get the screen (anything) to work. I’m wondering if the shield does more than just link the pins?
Any ideas
Of course I could have just wired it wrong, there ar so many wires & it it SO confusing
Yes, the shield has a 3.3v regulator and also a bunch of resistors for each of the signal lines (not sure how those resistors are configured but maybe used for level conversion)
I’m rebuilding from scratch so the screen shield will be incorporated in the prototype. Probably should have done that from the start.
The new version doesn’t have the resistors, anyway it doesn’t matter now I’m %70 through the rebuild but need sleep badly
The new version has logic chips that convert the 5V from the Arduino to the 3.3V of the display module, in addition to the 3.3V regulator. The old version has current limiting resistors to provide some additional protection to the inputs for the display which I assume are 5V tolerant. But the display operates at 3.3V and cannot be applied 5v power
All done all working
, except the Touch, which seems to have a life of its own.
Any thoughts on how I could dim the backlight and or turn the screen off while leaving the mega on, that wasn’t so hard when the shield wasn’t involved.
Good job. Although the library has functions for on/off and contrast, they are not implemented for the controller in the display you are using. There is a backlight pin, but don’t know how to use to dim the display. The other obvious mod is to tap the power line in the shield and install a relay
I’m thinking the back-light gets its power from the 3.3v, I could cut that pin & feed it from a PWM pin with a resistor inline to reduce the voltage. I dont know what mA the backlight draws though.
When I purchased the screen I thought it did the whole contrast on/off thing it was only when I read closer I realised it didn’t.
You could try using PWM pin to control the base of an n-channel bipolar transistor
Hmm, I’ll have to do some reading, I’m an electronics dummy
I assume what you are getting at is the n-channel bipolar transistor uses a separate power source for the back light & all the PWM pin does is vary the voltage coming out of the transistor.
You will be modulating the current through the backlight look for examples of LEDs with the transistor on the high side (next to the voltage source). In such case you will need a p-channel transistor. Seems the Backlight circuit does not have independent ground
I thought I’d just go with the relay option for the moment. I have disconnected both the 3.3v & the 5v that are next to each other on the Mega board but the screen is still getting power? I thought the other 5v power pins on the Mega weren’t connected to the screen.
I have looked at the shield schematic but I am schematic challenged
Any ideas?
According to the schematics, the 5V from Arduino is the only power pin feeding the display. It feeds a 3.3V regulator. You may want to trace the line coming into the regulator and measure the voltage.