Re: tiny12 lock bits
Hi Rooftop,
Since the SPIEN fuse is unprogrammed, the t12's ISP programming interface is disabled. You can only use HVSP to restore the SPIEN fuse. Erasing the chip resets the lock-bits but does not restore the fuses.
In order to re-enable the ISP programming interface, use the STK500 in high-voltage serial programming mode to program the SPIEN fuse, plugging t12 to the appropriate STK socket. You can find the latest STK500 user manual at the AVR Studio's on-line help system: Help > AVR Tools User Guide > STK500.
George