USBAsp firmware and schematic ?

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#1
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Guys,

Do you know where I can find a schematic and firmware for USBasp from china, I bought one and want to create myself USBasp....

I saw USBasp website, is it compatible with the chinese USBasp ?

Thanks

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Yes, the hardware is compatible. Most Chinese boards have additional 3.3V LDO regulator.
No, most Chinese USBASPs have superior firmware. e.g. auto-SCK

The Chinese firmware is probably locked.
The fischl.de firmware is openly available.

There are many alternative firmwares that will run on the USBASP hardware.

I suggest that you study the fischl.de schematic and source code.

David.

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Thanks for the information, and how can I upload the firmware to USBAsp I will make ? use my USBAsp (the one I bought from china) to upload it ? th port is from MOSI,MISO,SCK ?

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Why do you want to make a USBASP if you already own a perfectly good one ?

Just make a regular STK500 type programmer with your mega128 board.
Use this temporary programmer to upload different firmware to the Chinese board.

If you own an Arduino, you can make it into a temporary ArduinoISP.

Or simply flash out another $3.50 for another Chinese USBASP.

If you just want to experiment with V-USB projects, make the USB hardware interface with proper USB receptacle, zeners, resistors, capacitors.

The actual V-USB software can run on anything from a Tiny to your mega128.

David.

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I want to have an experiment on creating AVR programmer...I'm thinking on uploading the hex file into my new USBASP board with USBASP I have now...

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Well, just goforit.

AFIK, you understand hardware. If you have constructed the hardware according to the schematic, everything will work just fine.

Note that you need to use the exact components. Especially the zeners and 12MHz crystal.

David.

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Ok, I will follow your advice about the components, wish me luck

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In case you did not follow the importance of 300mW 3.6V zeners, you have to look at the voltage curves for < 1mA and not 10mA.

Big zeners start conducting 1mA below 2.5V even though they are rated for 3.3V at 100mA.

David.

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Is it ok using 3.3V ZD ? and why can't I read USBAsp I have using another USBAsp, I got "Chip Enable error", any workaround or it's somekind of reading protection ?
thanks

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Provide a part number for your "3.3V ZD" and its data sheet. Then look at its transfer curves.

Alternatively, simply apply 5V to R2 and read the voltage at D1 with your DMM. If it is between 3.0V and 3.6V then you are golden.

I would guess that you will read about 2.5V which is out of spec for the USB signal.
Then do some Ohms Law. (5.0V - 2.5V) / 68R = 36mA.

If you use the correct small 3.6V zener, you have (5.0V - 3.3V) / 68R = 25mA.

Now consider what happens with say 3.5V rather than 5.0V.
(3.5V - 2.5V) / 68R = 14mA
(3.5V - 3.3V) / 68R = 3mA

The BZY79 series are specified @ Iz = 5mA.
The BZY85 series are specified @ Iz = 80mA.
The 1N5333B is specified @ Iz = 380mA.

This is why you choose a BZY79C3V6 rather than a big zener.

Oh, you can read the USBASP firmware when you make jumper J2.

David.

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I'M USING A 328P TO MAKE A USBASP PROGRAMMER. I FALLOWED THE STEPS THAT CLAWSON MENTIONED  AND I PUT A FIRMWARE TO MY CHIP 328P USING USBTINYASP PROGRAMMER THROUGH THE BITBURNER. I LEAVE THE FUSER BITS THE WAY IT HAS IN MAKE FILE (BELONGS TO THE ATMEGA8).

THEN I TRIED TO PROGRAM ARDUINO UNO USING NEWLY CREATED USBASP PROGRAMMER THROUGH THE ARDUINO IDE AND THE BITBURNER. BUT IT GIVE ME ERROR WITH "RC=-1". THEN I CHANGED THE FUSER BITS TO LFUSE=62, HFUSE=D9, EFUSE=FF, THEN THE COMPUTER CANNOT RECOGNIZED THE PROGRAMMER.

THEN I TRIED TO INTALL THE DRIVERS AND IT COULDN'T (I'M USING WINDOWS 8.1 AND I TURNED OFF THE SIGNATURE SECURITY).

PLEASE CAN YOU HELP ME TO RESOLVE THIS PROBLEM. 

THARINDU GURUSINGHE

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What's wrong with your keyboard? Is the Cap locks button broken?

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly