ChipWhisperer Lite Capture 2: Troubleshooting ADC and CLKGEN Lock

1

Hardware: ChipWhisperer Lite Capture 2

I have been successfully experimenting with clock glitching on an external Arduino board for some time without any issues. However, today I encountered a problem where the LED indicators for ADC lock and CLKGEN lock are both blinking red. This issue occurs whenever I attempt to connect to the ChipWhisperer, such as when executing the command %run "Setup_Scripts/Setup_Generic.ipynb". While the ChipWhisperer is detected, the red LEDs suggest a potential issue with the clock and ADC.

What are the recommended steps or troubleshooting methods to address this issue? Any guidance or suggestions on resolving the ADC and clock lock problems would be greatly appreciated.

cwlite Device
sn = 50203220343043543130332032323039
fw_version =
major = 0
minor = 64
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 = 761455493
fifo_fill_mode = normal
clock =
adc_src = clkgen_x4
adc_phase = 0
adc_freq = 29538459
adc_rate = 29538459.0
adc_locked = True
freq_ctr = 0
freq_ctr_src = extclk
clkgen_src = system
extclk_freq = 10000000
clkgen_mul = 2
clkgen_div = 26
clkgen_freq = 7384615.384615385
clkgen_locked = True
trigger =
triggers = tio4
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 = False
glitch_lp = False
extclk_src = hs1
hs2 = clkgen
target_pwr = True
tio_states = (0, 1, 0, 1)
cdc_settings = bytearray(b’\x00\x00\x00\x00’)
glitch =
clk_src = target
width = 10.15625
width_fine = 0
offset = 10.15625
offset_fine = 0
trigger_src = manual
arm_timing = after_scope
ext_offset = 0
repeat = 1
output = clock_xor

2

That is pretty strange, on CW-lite those LEDs come straight from the FPGA PLL’s lock status and I’ve never seen them blink. What is the blinking rate (roughly)?

Can you try different USB cables / ports / host computers?

3

Hi @jpthibault, thanks for your answer. To address the situation correctly, as I mentioned in my post, the red blinking (ADC, CLKGEN) is only noticeable “once” (a quick red blink for few micro second, then off) after executing the following command, for example:

%run "Setup_Scripts/Setup_Generic.ipynb"
or scope.clock.clkgen_freq = 16E6

I’m not sure if that kind of blinking is considered normal behavior or not ? However, I can still see that ChipWhisperer’s locked status is True, and my host computer is able to identify it.

Unfortunately, I don’t have another host to test the ChipWhisperer. Is there any command that I can try instead to check the FPGA PLL status or something similar?

4

Ah, your original post didn’t make it clear that the blinking is only once and very brief. In that case, according to your description there is nothing at all to worry about. Whenever you change a PLL’s settings, it’s normal for it to become unlocked momentarily, and that is all that the red “lock failed” LEDs are indicating.