I have built a circuit for glitching PIC12F1822, an 8-bit MCU running from internal 8 MHz oscillator. The code that’s running on the PIC is similar to the XMEGA code from the Fault 101 tutorials:
loop: if serial command received: set trigger high increment variable set trigger low send variable over uart goto loop
I’ve been trying to find the correct voltage glitch parameters for over a day now. The procedure I follow is:
- Find the glitch parameters which will result in about 20% target reset (this step is working)
- Select a point in time after the trigger
- Inject a number of glitches around that point and watch for unusual output from the UART (the only results are a normal output or a reset)
So far nothing I do works, and I’ve done quite a bit of experiments. I hope that means I’m missing something and not that the PIC micro is immune to voltage glitching. The glitch settings are:
glitch = clk_src = clkgen width = 46.09375 width_fine = 0 offset = 1.171875 offset_fine = 0 trigger_src = ext_single arm_timing = after_scope ext_offset = 14 repeat = 19 output = glitch_only
The CW clock is set to 64 MHz.
My strategy will benefit from some comments.