How to connect CW305 via python?

I have a trouble connecting my CW305 via python.
I installed “Chipwhisperer.v5.5.0.Setup.64-bit.exe” directly for my windows computer.
When running below code it showed that USB Device no found.
But device manager has recognized CW305!

Did I miss some installation/operation steps so it doesn’t work?

from chipwhisperer.capture.targets.CW305 import CW305
import chipwhisperer as cw
bitstream_file = r"D:\APP\ChipWhisperer5_64\git\home\portable\chipwhisperer\hardware\victims\cw305_artixtarget\fpga\vivado_examples" \

scope = cw.scope()
self.scope = scope

target =, fpga_id='35t',bsfile=bitstream_file, force=False) = target

OSError Traceback (most recent call last)
5 r"\aes128_verilog\aes128_verilog.runs\impl_35t\cw305_top.bit"
----> 7 scope = cw.scope()
8 self.scope = scope

d:\app\chipwhisperer5_64\git\home\portable\chipwhisperer\software\ in scope(scope_type, sn)
226 from chipwhisperer.common.utils.util import get_cw_type
227 if scope_type is None:
–> 228 scope_type = get_cw_type(sn)
229 scope = scope_type()
230 try:

d:\app\chipwhisperer5_64\git\home\portable\chipwhisperer\software\chipwhisperer\common\utils\ in get_cw_type(sn)
501 name = “”
502 if len(possible_sn) == 0:
–> 503 raise OSError(“USB Device not found. Did you connect it first?”)
505 if (len(possible_sn) > 1):

OSError: USB Device not found. Did you connect it first?


If you’re just connecting the CW305, you can skip the scope = cw.scope() part and just run

target =, cw.targets.CW305, fpga_id='35t', bsfile=bitstream_file, force=False)

I’d recommend taking a look at for basic usage and for API documentation.


Thank you, now it is working fine.

I have other questions.

Is it possible to generate clock glitch and voltage glitch like below image only using CW305 board?

How can I read the output signals (i.e. values stored in registers) of FPGA on CW305 board by python?

No, you’ll need a ChipWhisperer capture board (Nano, Lite or Pro) for that.

You can read/write register values via target.fpga_read() and target.fpga_write(), which are implemented here: