rem100: EM100-Pro library and command-line utility

rem100 provides both:

• the em100 Rust library for controlling Dediprog EM100-Pro hardware; and
• the rem100 command-line utility built on that library.

It supports both the original EM100-Pro and the newer EM100-Pro-G2.

The 'em100' device provides a way to emulate a SPI-flash chip. Various connectors are available to allow it to take over from the in-circuit SPI chip so that the SoC sees the em100's internal memory as the contents of the SPI flash. Images can be loaded into the em100 over USB in a few seconds, thus providing a much faster development cycle than is possible by reprogramming the SPI flash each time.

Features

Major features provided by the tool include:

• Set the chip being emulated (the tool supports about 600)
• Adjust the state of the hold pin, which supports overriding the internal SPI
• Use of several em100 devices, distinguished by their serial number
• Terminal mode, allowing the SoC to send messages
• Output a trace of SPI commands issued by the SoC
• Reading / writing em100 firmware (dangerous as it can brick your em100)

Linux USB Permissions

On Linux, you need to set up udev rules to access the EM100 without root permissions. Create a udev rule:

echo 'SUBSYSTEM=="usb", ATTR{idVendor}=="04b4", ATTR{idProduct}=="1235", MODE="0666", TAG+="uaccess"' | sudo tee /etc/udev/rules.d/99-em100.rules
sudo udevadm control --reload-rules
sudo udevadm trigger

Then unplug and replug the EM100.

Installation and library use

Command-line utility

Install the rem100 binary from crates.io:

cargo install rem100

For a local build:

cargo build --release --bin rem100

The binary will be available at target/release/rem100.

Rust library

The crates.io package is named rem100, while its library crate is named em100. Disable the default cli feature when only the library is needed:

[dependencies]
rem100 = { version = "0.1", default-features = false }

use em100::{list_devices, Em100, Result};

fn main() -> Result<()> {
    for (bus, address, serial) in list_devices()? {
        println!("{bus}:{address} {serial}");
    }

    let device = Em100::open(None, None, None)?;
    println!("{}", device.serial_string());
    Ok(())
}

The core native library API does not require the cli feature. CLI-only downloading and archive helpers are behind cli.

Web Interface

A GUI interface is available in two variants:

Native Desktop GUI

cargo run --no-default-features --features native-gui --bin rem100-web

Web (WASM) Interface

A WebUSB-based web interface using egui/eframe:

# Install trunk (if not already installed)
cargo install trunk

# Build and serve the web interface
trunk serve

Then open http://127.0.0.1:8081 in Chrome or Edge (WebUSB is not supported in Firefox).

Note: The Linux udev rules above are also required for the web interface.

For detailed web interface documentation including architecture, feature flags, and development setup, see README-web.md.

A prebuilt web version is available at https://rem100.9elements.com.

Usage

Example:

rem100 --stop --set M25P80 -d file.bin -v --start -t -O 0xfff00000

Command-line options

-c, --set CHIP                      Select chip emulation
-d, --download FILE                 Download FILE into EM100pro
-a, --start-address ADDRESS         Start address for download (e.g., -a 0x300000)
-m, --address-mode MODE             Force 3 or 4 byte address mode
-u, --upload FILE                   Upload from EM100pro into FILE
-r, --start                         Start emulation
-s, --stop                          Stop emulation
-v, --verify                        Verify EM100 content matches the file
-t, --trace                         Enable trace mode
-O, --offset HEX_VAL                Address offset for trace mode
-T, --terminal                      Enable terminal mode
-R, --traceconsole                  Enable trace console mode
-L, --length HEX_VAL                Length of buffer for traceconsole mode
-b, --brief                         Brief mode for traces
-F, --firmware-update FILE|auto     Update EM100pro firmware (dangerous)
-f, --firmware-dump FILE            Export raw EM100pro firmware to file
-g, --firmware-write FILE           Export EM100pro firmware to DPFW file
-S, --set-serialno NUM              Set serial number to NUM
-V, --set-voltage [1.8|3.3]         Switch FPGA voltage
-p, --holdpin [LOW|FLOAT|INPUT]     Set the hold pin state
-x, --device BUS:DEV                Use EM100pro on USB bus/device
-x, --device EMxxxxxx               Use EM100pro with serial no EMxxxxxx
-l, --list-devices                  List all connected EM100pro devices
-U, --update-files                  Update device (chip) and firmware database
-C, --compatible                    Enable compatibility mode (patch image for EM100Pro)
-D, --debug                         Print debug information
-h, --help                          Display help text

License

This project is licensed under the GNU General Public License v2.0 only - see the COPYING file for details.

References

[1] https://www.dediprog.com/product/EM100Pro-G2