AVR-Dopper in HVSP propably cannot work for t11/t12/13!

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AVR-Dopper in HVSP propably cannot work for t11/t12/13!

Post by butrus.butrus » Wed Sep 12, 2007 8:12 pm


I tried to look and compare the datasheets for HVSP and I found, that the HVSP algorithm differs for ATtiny45(etc) and ATtiny11/12 and for ATtiny13! It seems, that in order to get the device's singature into the latch one must pulse at least 6x (t13) or 4x (t11/t12) the SCI clock before bringing the RESET into 12V (see the datasheets for more details).

I would be glad to help with debugging any new firmware, but ATM I only have tiny11 and tiny12 to try.

(BTW, maybe it wouldn't be bad idea to add the possibility to "debug" the 12V wiritng by extending the firmware to listen for a specific vendor command that would put the HVSP reset line into 0V/5V/12V on user request. It would be easier to see whether something with the analog circuit is wrong or there is another - software - problem..)

And Yes, Christian, do You have plans to support PP in some future version? I have seen some code in the hvprog.c. Do you think ATmega16 (or compatible) would be enough for a complete ICP/HVPP/HVSP programmer?

(And Yet another note, I have look at the specification of HVPP initialization for M8 and M16 and seems really strange: one has to "clear" some fuses if for example the RESET bin is disabled BEFORE starting HV programming :-((((( )

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Post by christian » Mon Sep 17, 2007 6:22 pm

I have heard reports that some of the 8 pin devices don't work in HVSP mode, maybe due to the difference you found! I have not gone through all the tedious diagrams in all data sheets when writing the original firmware.

I'm quite confident that the Tiny11/12, 13 and 45 can be programmed in the same way, the STK500 would have to know the device type otherwise. If you make a firmware change, I can easily test it with a Tiny45 and an old AT90Sxxx here. I don't have a Tiny11 or 12, though.

The code is prepared to support HVPP mode, but the Mega8 does not have enough pins. An ATMega16 should be sufficient for that. I don't have plans to support this mode myself because I never found ISP a limiting factor with the bigger devices. But if you want to start this project, I can give you hints.

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