This page is about the "production" version of the setup described in ICE40_based_passive_tap.
It is a bi-directional, high-impedance passive tap for E1 (PRI/S2M) tracing. It traces both directions of a link simultaneously via two LIU (Line Interface Units) attached to an iCE40 FPGA with E1 framer + USB softcores.
The traces are sent as isochronous USB transfers to the host PC, where they can (for example) be stored on disk.
Hardware files can be found at: http://git.osmocom.org/osmo-e1-hardware/tree/hardware/e1-tracer and are available as Open Source Hardware.
We originally started with a prototype from an iCE40 evaluation board plus two osmo-e1-xcvr and one e1-tap as described in ICE40_based_passive_tap.Meanwhile, we have designed a fully integrated board. Design files are part of the
- Board layout
- Bill of Materials
gateware + firmware¶
The FPGA gateware and RISC-V softcore firmware are found in the
osmo-e1-hardware.git repository, under the
firmware/ice40-riscv/e1-tracer directories respectively.
Fully assembled products based on this hardware are going to be made available by sysmocom
The host software is found in the
e1-recorder branch of
ice40playground.git, see https://github.com/smunaut/ice40-playground/tree/e1-recorder/projects/riscv_usb/sw
There are two related programs:
main- the program used to perform recordings and store them
dump- the program to analyze recordings