My son Paul is the author of this guest post.
This Arduino sketch is useful for rescuing ATtiny microcontrollers rendered useless by incorrect fuse settings. It does this by putting the bricked tiny into high-voltage serial programming mode and writing the fuses to safe values.
Connection Diagram
Click to enlarge
The Arduino is connected to the tiny though 1k resistors and a 2N3904 transistor is used to switch 12 volts applied to the tiny’s reset pin. After uploading the sketch the Arduino sends “Hello?” repeatedly until
communications are established by sending a byte through the serial monitor. The Arduino then programs the fuses.
Serial Monitor log
Hello?
Hello?
Hello?
1
Entering programming Mode
lfuse reads as 62
hfuse reads as 5F
efuse reads as FF
Writing hfuse
Writing lfuse
lfuse reads as 62
hfuse reads as DF
efuse reads as FF
Exiting programming Mode
Download the program: hv_serial_prog.pde
Based on work by Jeff Keyzer.
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