CoolRunner-II Starter Board: Advanced Development Platform for Xilinx CPLD
The CoolRunner-II Starter Board serves as a robust, USB-powered circuit development platform for Xilinx's CoolRunner-II CPLD, integrating efficient power management, flexible clock options, and comprehensive I/O features. Designed for complex digital design and prototyping, this board facilitates seamless external circuit integration with five expansion connectors, exposing 64 CPLD signals.
Key Features and Capabilities
- Powerful CPLD in Compact Package: The board features a 256-macrocell CoolRunner-II CPLD in a TQ-144 package, balancing high processing capability with a compact footprint.
- Multi-Function USB2 Port: Provides board power, JTAG programming, and data transfers, offering flexibility and ease of use in a single interface.
- Flexible Clocking: Includes an 8MHz fixed-frequency oscillator, plus a socket for an optional crystal oscillator, supporting diverse application needs.
- Expansion Options: 64 I/O signals available through four Pmod connectors and a 40-pin parallel connector, allowing extensive peripheral integration.
- Integrated EEPROM: Equipped with a DS28E01Q EEPROM for additional memory requirements.
Configuration and Programming
To function, the CoolRunner-II board’s CPLD must be configured by the user, either through schematic diagrams or HDL code, using Xilinx's free ISE WebPack software. Configuration files are transferred via USB with Xilinx's iMPACT software or an external programming cable. The CPLD retains its programmed state indefinitely, reinitializing to the last loaded configuration upon power-up. This flexibility allows users to update configurations dynamically, redefining the board’s behavior as needed.
Power Supply Options
The CoolRunner-II board can draw power through its USB port or an external source via the JP3 connector, with jumper JP2 switching between USB and external power. When using an external power source (4.5V to 9V), it is routed through a Maxim LT3028 regulator to provide the CPLD’s required 3.3V I/O and 1.8V core voltages. The four-layer PCB design, with dedicated VCC and GND planes and strategically placed bypass capacitors, ensures a stable and low-noise power supply, ideal for sensitive digital applications.
Clocking
The primary 8MHz oscillator output, routed to the CPLD’s GCLK2 pin, offers a stable clock source, while an additional socket is available for a standard half-size DIP oscillator, offering flexibility for custom clock rates.
User I/O Interface
Designed for intuitive operation, the CoolRunner-II board includes:
- Inputs: Two pushbuttons and two slide switches with built-in short-circuit protection.
- Outputs: Four red LEDs and a four-digit LED display, providing immediate visual feedback.
- Power Indicators: LEDs indicating USB power good (LD4), board power good (LD5), and USB link status (LD6).
Expansion Connectors
Supporting versatile expansion, the board includes:
- Four 12-Pin Pmod Connectors: Each connector provides two VDD and GND connections and eight unique CPLD signals, accommodating a variety of Pmod modules, such as speaker, H-bridge, and sensor modules.
- 40-Pin Expansion Connector: Supplies three power signals and 37 individual I/O signals, facilitating extensive external circuit integration.
With the rapid advancement of technology, CoolRunner-II CPLD has been retired, and other CoolRunner-II products may also gradually withdraw from the stage of history. However, the innovations they brought in digital circuit development and low-power design have provided strong support and valuable experimental platforms for engineers and developers. Their influence will continue to inspire future technological development and leave a profound mark on the field of electronic engineering.
