• A single 3.3V supply voltage (voltage regulation provided on Cmod board where required)
• Adequate bypass capacitance on all CPLD voltage supply pins
• All available user I/O signals brought out to DIP pins
• Once programmed, CPLD designs are non-volatile

Cmod boards combine a Xilinx CPLD, a JTAG programming port, and power supply circuits in a convenient 600-mil, 40-pin DIP package. Cmods are ideally suited for breadboard or other prototype circuit designs where the use of small surface mount packages is impractical.

Cmods were created to make the latest Xilinx CPLDs more practical for experimental and prototype circuits. They can plug directly in to breadboards or IC sockets, and they can mate with the Digilent Ceres board to utilize a collection of ready-made I/O circuits. Cmods are available with CoolRunner-II CPLD C2. C-Mod boards are especially useful for investigating designs across a variety of CPLD families.

Cmod boards, which measure just 0.7" by 2.16", allow designers to experiment with CPLD-based designs in a variety of state-of-the art devices. Designs can easily be ported from one Cmod to another, so that design performance in different devices can be compared and contrasted. The 40- pin DIP form factor allows Cmods to be used in breadboard or other through-hole circuits where surface-mount devices are impractical. They can be configured with a wide range logic circuits, from simple logic functions to sequential controllers. All available CPLD I/O signals are routed to the 40-pin DIP connections.

When used in conjunction with the Ceres board, Cmods can be used to rapidly implement CPLD based circuits, or to gain exposure to Xilinx CAD tools and CPLD-oriented design methods. The Ceres board provides Cmods with a power supply, a clock source, input buttons and switches, and various output LEDs. The Ceres/Cmod combination makes an excellent platform for use in teaching labs.

Cmods are programmed with a sample design during manufacturing. This design, available at the Digilent website, can be used to verify Cmod/Ceres function. It also provides a simple reference design example of a Xilinx project.