COR24-TB FPGA Development Board

The COR24-TB FPGA Development Board was created to aid in the demonstration and development of the COR24 soft CPU. This board, powered by a Lattice Semiconductor MachXO* FPGA, is a small computer system, with a console, via an externally connected USB/UART bridge, 1 MB of SRAM, and several I/O pins that may be used for I2C, SPI, or other general purposes. The COR24-TB is shipped with the latest version of the open-source COR24 soft CPU. The COR24 CPU is written in Verilog, and the full project, for use with Lattice's "Diamond"* FPGA development software, is available for download from this site.

This board can be used to develop and test many different kinds of programs, to exrecise various aspects of the COR24 CPU architecture, and the I/O that is included on the COR24-TB. Several demonstration programs, their images loadable through the high speed (921600 baud) serial port, are included in the downloadable archive.

OR, this board can be used as a general purpose Lattice MachXO* FPGA development tool. The FPGA bitstream can be programmed through a JTAG conector, using the Lattice HW-USBN-2B programmer,  from a Lattice Diamond* project. So you can write your own HDL code, and you are free to use all the code provided in the COR24 project (UART, SRAM access, etc.), under an MIT open-source license.

* Lattice MachXO and Lattice Diamond are trademarks of Lattice Semiconductor, Inc.

COR24-TB connected to a USB/UART bridge, on the small breadboard, via one of the I/O connectors; connected to Lattice HW-USBN-2B programmer through the JTAG connector, oscilloscope probe on the on-board oscillator output.

On-board oscillator output, into FPGA, 33.9 MHz, +/- 0.5%. The COR24 CPU uses the FPGA's PLL to multiply this by 3, and runs at 101.7 MHz, +/- 0.5%.

COR24-TB features:

- Lattice LCMXO2280C-5TN144C FPGA

- ISSI IS61WV10248EDBLL-10TLI 1 MB SRAM

- Onboard oscillator, input to FPGA, 33.9 MHz +/- 0.5%

   (COR24 CPU project uses PLL to run at 3x, or 101.7 MHz, +/- 0.5%)

- USB mini-B power (only) connector +5V/GND

- USB/UART bridge support, e.g. FTDI FT232R, or any similar module, at 921600 baud

- JTAG header for use with Lattice HW-USBN-2B programmer

- Multiple +3.3V and board GND sources for use by external circuitry (100 mA)

- 10 general purpose I/O pins

- 1 user LED, 1 user input pushbutton switch

- Reset button