The goal of this project is to build a brute-force decoder for traditional PAL and GAL (such as 22V10) programmable logic parts. The implementation is not complete, but at this point, it can decode simple combinatorial gate devices to point which looks similar to what WinCUPL might take as input.
The rev1 directory contains board design files for the first version of this board. There is a bug in the design which causes 5V to always be applied to the inserted PLD's VCC rail, although some protection can be afforded as the PLD's GND rail is correctly switched by firmware. This bug is fixed in the Rev 2 design.
The rev2 directory contains board design files for the second version of this board. This is the current version of Brutus. Improvements over the first version include bug fixes, the addition of a PLCC-20 socket, options for both narrow and wide DIP sockets, and optional LEDs which can show the state of each of the 28 pins for analysis progress.
The fw directory contains STM32 firmware for all board revisions. You will need to change the Makefile to build for the rev1 board, if you have that design.
The sw directory contains software which runs on your Linux or MacOS host to do analysis of the output from the STM32 firmware. With current software, you must manually capture to a file the terminal output from the firmware. The host software can then perform an analysis on the captured file and provide decoded operations.
As this is still a work in progress, there is still much debug output scattered throughout both the software and firmware.
Acquiring the Brutus board files, software, and firmware:
git clone https://github.com/cdhooper/brutus28
Building Brutus host-side software from Linux:
cd brutus28/sw
make
Building Brutus firmware from Linux:
git clone https://github.com/cdhooper/brutus28 cd brutus28/fw make
Setting up permissions
-
Depending on your particular OS and version, you will likely need to allow
your user access to have direct interation with Brutus and the programming
hardware. In most versions, the easiest way to get access to the /dev/ttyACM*
devices is to add your user to the dialup group. You'll need to logout and
back in before permission changes take effect. For other USB interfaces,
such as for DFU programming or ST-Link, it may be easier to create a new
rule in /etc/udev/rules.d. Here is an example file "70-stm-rules" as a
starting point:
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0483", ATTRS{idProduct}=="3748", MODE="0666"
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0483", ATTRS{idProduct}=="df11", MODE="666"
Installing Brutus firmware on the Brutus-28 board from Linux (DFU method):
- Connect the board to your computer via the USB-C port
- Hold down the Abort button and then press and release the RESET button. Continue holding the ABORT button for three seconds.
- Wait about 10 seconds and a new device should appear on your Linux host. As seen by lsusb:
Bus 001 Device 032: ID 0483:df11 STMicroelectronics STM Device in DFU Mode<
- In the brutus28/fw directory, type make dfu
- After firmware programming is complete, you may need to press the reset button on your Brutus board. DFU mode exit does not always drop the USB link. You should notice the Green power LED illuminate on your Brutus board.
Installing Brutus firmware on the board from Linux (ST-Link method):
- Connect the board to an ST-Link device, making sure that all pins are connected to their proper positions. The Brutus ST-Link connector pinout is identical to the one on the STM32F4-Discovery board, so if you have one of those boards and a ribbon cable, it's an easy connection.
- Connect the ST-Link to your PC by USB (on the STM32F4-Discovery board, this is the USB Mini-B port).
- In the brutus28/fw directory, type make flash
- After firmware programming is complete, you should notice the Green power LED illuminate on your Brutus board.
Capturing and analyzing
- Install the IC to analyze in a compatible socket with pin 1 of the chip facing pin 1 of the socket.
- Set the VCC and GND jumpers as appropriate for your device. Pin 28 is typically VCC with most parts. Note that if you are installing a DIP IC with less than 28 pins, then pin 28 will correspond to the highest pin number of your device.
- Connect the Brutus board by USB to your computer. It is not necessary to unplug Brutus while changing chips to analyze. Power is automatically removed from the chip when it's not in use.
- There is not yet an easy way to capture from Brutus. Under Linux, I use a program I wrote called term for this. Example:
echo pld walk dip18 -9 -18 raw | term /dev/ttyACM0 > chip.cap
- Once you have a capture file, you can then run the software to analyze it.
brutus chip.cap -d dip18
The output from the brutus utility includes an analysis followed by logic statements in a format compatible with the WinCUPL language used for programming Lattice parts.Further information will eventually be made available here: http://eebugs.com/brutus28