I am using CW lite to test voltage glitching on an STM32G0 microcontroller. I’ve set up a really basic test circuit with 10 ohms shunt resistor, and the CW connected to the board via a coaxial cable. Currently I am able to glitch the target somewhat successfully, but I’d like to ask a few questions.
The picture below shows a capture of a glitch without the target being in the circuit. The glitch shape is fairly distinct.
The second image show the same glitch issued when the target is in place. No external components are added to the circuit:
Now the crowbar circuit cannot pull the rail to ground; that only happens at the end of the glitch. The MCU gets reset though. Here are my scope settings:
cwlite Device
fw_version =
major = 0
minor = 50
debug = 0
gain =
mode = high
gain = 30
db = 24.8359375
adc =
state = True
basic_mode = rising_edge
timeout = 2
offset = 0
presamples = 0
samples = 5000
decimate = 1
trig_count = 1040748980
fifo_fill_mode = normal
clock =
adc_src = clkgen_x1
adc_phase = 0
adc_freq = 99999996
adc_rate = 99999996.0
adc_locked = True
freq_ctr = 0
freq_ctr_src = extclk
clkgen_src = system
extclk_freq = 10000000
clkgen_mul = 25
clkgen_div = 24
clkgen_freq = 100000000.0
clkgen_locked = True
trigger =
triggers = nrst
module = basic
io =
tio1 = serial_rx
tio2 = serial_tx
tio3 = high_z
tio4 = high_z
pdid = high_z
pdic = high_z
nrst = high_z
glitch_hp = True
glitch_lp = False
extclk_src = hs1
hs2 = clkgen
target_pwr = True
tio_states = (0, 0, 1, 0)
cdc_settings = bytearray(b'\x00\x00\x00\x00')
glitch =
clk_src = clkgen
width = 48.828125
width_fine = 0
offset = 10.15625
offset_fine = 0
trigger_src = manual
arm_timing = after_scope
ext_offset = 101
repeat = 100
output = enable_only
I’d like to know what could be causing that behavior, and if there’s a way for rectifying it. I will also use the topic for asking a few other things:
- What is the difference between glitch_hp and glitch_lp, and more importantly, what factors should we concider when selecting one or the orher?
- Can they be used simultaneously?
Thanks