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아두이노 센서 ATMEGA128 PWM LED 초음파 AVR 블루투스 LCD UART 모터 적외선


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작성자 키트 작성일2017-08-22 16:29 조회1,870회 댓글0건

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VGA on ATmega128

Although I've done VGA signals from micro controllers many times before, I've been pondering lately on introducing a 74LS165 PISO shift register into the circuit. This would increase the resolution from the controller based on the memory available. I'm aiming for 40x25, but I wouldn't be surprised if it were capable of more.

I didn't finish it last night, but I'll show you the progress so far. Here's the breadboard with the shift register attached, and a crystal to it. I also decided to do all, if not most of it, in pure C.

ATmega128 VGA on breadboard

Here's a quick VGA adapter board I made. Who said vero boards are passe?

ATmega128 VGA adapter

Here's the graphics being produced by the ATmega. Not much to show, really, but I was able to verify that the timing was spot-on and the voltage levels were acceptable.

ATmega128 graphics output on the oscilloscope

It's at a very experimental stage right now, I'm only setting the background color, playing with a few on/off's horizontally. The image is perfectly stable, no flickering or shivering.

ATmega128 VGA screen

Here's proof the signal is fine. For some reason I expected 60Hz but ended up with 59... not quite sure why, but we'll see if it's worth digging into. As of now, I don't really care.

ATmega128 VGA screen verification

All right, that's as far as I got last night. Next time I'll have some text on the screen! Oh, and the schematics and sources will obviously be released when I'm done.

Edit: Success. See here.


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 3660040653_8riWzKwv_t.png 3660040653_mQsDI3cS_r.png 3660040653_WZzC3AoI_su.png

 

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  • …A on the ATmega, and fought some timing issues. This is a followup on the test I did earlier ("VGA on ATmega128"), but today, I got a small breakthrough and a proof-of-concept up and running:It's based on a…

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vgavr

About
VGAVR is a simple program for generating text on a VGA monitor using a 16MHz ATmega MCU.

The source is written in 100% C and was developed on an ATmega128 using AVR Studio 4. It is believed to run just fine on other ATmegas at the same speed.

It has been tested on two monitors, and should comply to the 640x480@60Hz industry standard. However, do note that it is currently at a beta stage, so some tweaking may be required.

License
VGAVR is released under the GNU General Public License, see this page for details.

Download
The source can be downloaded here: vgavr-0.3b.zip (dated 2012-08-27)

Hook it up
R, G and B has a voltage level of max 0.7v, so the graphics output pin (MOSI, PB2 on ATmega128) must be via a divider to obtain the correct voltage level. VSYNC and HSYNC are TTL levels and does not require a divider.

Sample layout

Screenshots
3660040653_KXYaNGoc_vgavrscreenshot.jpg

3660040653_VQ2LtBSK_vgavrcloseup.jpg

 

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