Reading Locked Flash Rom

hajix · Joined: 19 Apr 2006 Posts: 15

hello,
I'm using a Atmega16 MCU in my project.
it's written by someone else and lockbit 1 & Lockbit 2 are enabled.
when i use my programmer to read it, the buffer will be full of ascii codes from 0 to 255.
so how can i read the flash rom?
help me.......... Sad

Luciano · Joined: 29 Nov 2004 Posts: 3149 Location: Italy

Hi,

The Lock bits can only be erased with a chip erase command.
During a chip erase the flash memory and EEPROM memory are erased.

Best regards,

Luciano

cloudnine · Joined: 29 May 2007 Posts: 58

Hi there, on this topic, I have two ATtiny2313's that i have set the fuse bits incorrectly and now the chip is "locked" when I go and compile and send a program to it, I have tried the external crystal set up AND set up an external clock system and neither appear to unlock the chips any advise anyone. Or even send me to a forum here if the answer has already been published. Many thanks again

Luciano · Joined: 29 Nov 2004 Posts: 3149 Location: Italy

Hi,

You have disabled the RESET pin. (RSTDISBL fuse bit).

You need a programmer supporting the High-voltage
Programming mode like the Atmel STK500.

Best regards,

Luciano

cloudnine · Joined: 29 May 2007 Posts: 58

Well, once again I thank you for you assistance. Much appreciated but not having the stk500 I will have to put it down to experience and be more coareful. I am fortunate enough to purchase these micro's for "loose change' so not to much loss.