The following section details the features and support for the CPLD Demonstration Board.
The demonstration board uses a surface-mounted 555 timer, with resistor and capacitor values set for 14 Hz operation. This oscillator clocks a simple test design (a Johnson counter) implemented in the XC9536; this counter drives LEDs used to verify operation.
The CPLD Demonstration Board is shipped with two short "ribbon" style cables for device configuration. The board also supports the Parallel Cable III and the XChecker (serial) cables.
Make sure to connect the cables properly to your host and target system. For information on connecting cables and powering up the demonstration board, refer to the “Cable Hardware” chapter.
This demonstration board is supported by the JTAG Programmer Software. For more information about using this software, refer to the JTAG Programmer Guide.
The Printed Circuit Board is shipped with a 44-pin VQFP XC9536 device with two bypass capacitors, 8 LEDs with current limiting resistors, and a header for attaching the download cable.
The PCB will accept a DPDT switch or a permanent jumper at location SW1. The switch is used to connect or disconnect an external DC voltage from the +5V regulator.
A prototyping area is included on the PCB. This area has 299 holes (13 columns x 23 rows) for attaching additional circuitry. The holes are 0.038 inch diameter on 0.10 inch centers. Two pairs of these holes are connected to + 5V and GND along the left side of the prototyping area.
The Demonstration Board allows the attachment of an external regulated +5V power supply via the pads at J2. If a +5V regulator is installed at location U2 with a 22uF (or larger) filter capacitor at C4, an external DC voltage of 7V to 12V can be applied at location J3.
You can also install an outer case, battery, 5V regulator, filter capacitor, and on-off switch on the demonstration board. These power supply components can be purchased from Digi-Key, as shown in the following table.
| Quantity | Description | Reference | Digi-Key Part Number |
|---|---|---|---|
| 1 | DPDT Switch, right angle | SW1 | EG1909 |
| 1 | 5V, 1A, low dropout reg. | U2 | LM2940CT-5.0 |
| 1 | 22uf, 16V, Tantalum cap. | C4 | P2040 |
