Avr too slow?

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uze6666
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Re: Avr too slow?

Post by uze6666 »

What device are you using to program the chip (i.e ARVISP, etc?) and which software (AVRDUDE)? After you get an oscillator module if you still have some problems it could well be the fuses. Wrong fuses is a very common cause of all sort of glitches as you described. From the wiki page http://uzebox.org/wiki/index.php?title= ... itch_noise:
No image and High pitch noise

There's nothing in the screen or bunch of random lines/dots appears
The sound is a horrible high pitched noise out the speaker

Mega644s ships with CKDIV8 AND JTAGEN activated and *must* be uncheked/unprogrammed. CKDIV8 internally divides the master clock by 8, so your Uzebox runs at 3.57Mhz. No chance it will generate video with that! Also JTAGEN activates the debug port, which is on the VIDEO DAC port and will screw up some color component if left active.
Insure *only* these fuses are written (this means checked in AVRStudio) (written fuse=0, unwritten fuse=1):
IF you are using a crystal:
-SPIEN (pre-written in the factory)
-EESAVE
-CKSEL3
-SUT1
-These fuses correspond to a setting of 0xD7 for lfuse and 0xD7 for hfuse
IF you are using an oscillator module:
-SPIEN (pre-written in the factory)
-EESAVE
-CKSEL0
-CKSEL1
-CKSEL2
-CKSEL3
-SUT0
-SUT1
-These fuses correspond to a setting of 0xC0 for lfuse and 0xD7 for hfuse
EESAVE preserves the eeprom between flash writes (will be useful later on). CKSEL=0111 SUT=01 starts with a full swing oscillator 16K delay+0ms.
anercomp
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Joined: Fri Jan 09, 2015 4:16 pm

Re: Avr too slow?

Post by anercomp »

So i tried a few things and now it works with the help of a 74HC14 as oscillator :mrgreen: :mrgreen: :mrgreen: :mrgreen: will buy the controllers now :D
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uze6666
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Joined: Tue Aug 12, 2008 9:13 pm
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Re: Avr too slow?

Post by uze6666 »

Great news! :P For the benefits of other that may hit the same snags in the future, can you elaborate a bit what you did? Thanks!
anercomp
Posts: 10
Joined: Fri Jan 09, 2015 4:16 pm

Re: Avr too slow?

Post by anercomp »

Here is what i did, Hope You guys can read it :D
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