XC9500XL CPLD breakout board

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Project Summary
Name: XC9500XL CPLD breakout board
Buy it: Get one for $15 at Seeed Studio
Price: $15
Status: Test production
Manufacturing: Shipping
Forum: XC9500XL CPLD breakout board Forum
Xc9572-cpld-breakoutvib.jpg

Ever get stuck choosing the right logic chip combination or voltage level translator? Give up the hunt and create your own custom logic chip. CPLDs can give you the logic you need, with the pinout you want, while saving board space and board revisions.

The Xilinx XC9500XL family has some of the cheapest and readily-available CPLDs. This development board from Dangerous Prototypes will help you build your first custom logic chip using simple schematic entry, Verilog, or VHDL.

  • XC9572XL CPLD with 72 macrocells
  • 5volt tolerant inputs
  • On-board 3.3volt power supply for core and pins
  • Selectable 3.3volt or external supply for pins (1.8volt to 3.3volt)
  • LEDs for output
  • Push button for input
  • Populated JTAG header
  • Unpopulated oscillator footprint on the bottom
  • Easy to program with the Bus Pirate
  • Pre-programmed with LED inverse toggle demo
  • Open source (CC-BY-SA)

Available for $15 at Seeed Studio

Contents

Overview

XC9572XL-CPLD-breakout-dia.png

Hardware

Cct-XC9572XL-CPLD-breakout-lv.png

Click for a full size schematic image. Schematic and PCB were designed with the freeware version of Cadsoft Eagle, download the latest project files from our Google Code project SVN.

XC9572XL CPLD

XC9572XL-CPLD-breakout-cpld.jpg

The XC9572XL (U1) is a 72 macrocell CPLD with 5volt tolerant pins. It is one of the smallest CPLDs made by Xilinx, and is readily available from Digikey for around $2.40.

The CPLD core requires a 3.3volt supply to each VINT pin. This supply is provided by the on board 3.3volt regulator.

The IO pins operate from a separate supply of 1.2volts to 3.3volts. An external supply can be connected to either IO pin, or place a jumper on VIO to connect the on board 3.3volt power supply.

Each supply pin has a 0.1uF capacitor (C1,C2,C3,C4).

The JTAG programming pins are brought to header JT. The JTAG interface is powered by the 3.3volt core supply.

Power supply

A 3.3volt regulator (U2) powers the CPLD core and (optionally) the IO pins. C5 and C6 are 3.3uF input and out capacitors. Capacitor C7 is an optional feedback bypass capacitor that can be used with some voltage regulators, it is not used here.

The 3.3volt regulator is supplied through pin V+. The supply can be up to 5volts. Up to 100mA is available from the 3v3 pin when using the on-board regulator.

LED PWR lights if the power supply is active.

Button and LEDs

XC9572XL-CPLD-breakout-userio.jpg

Two LEDs (D1, D2) and a push button (PB) are included for a little user IO.

LED D1 and D2 source current from the CPLD. Generally, designers sink current from CPLDs and FPGAs - the chip connects the LED to ground instead of power - because many parts can sink 20mA but only source a few. On this chip, however, the maximum current is a paltry 8mA for both source and sink. The LEDs have 2K resistors (R2,R3) that keep the current at an acceptable 2mA.

A push button (PB) provides a way for user input. Resistor R1 holds the CPLD pin high when the button is not pressed. When the button is pressed the pin is connect to ground and taken low.

Pinout table

Pinout
FB4/2 DescriptionDescription FB3/FB1
GND Ground connection Ground connection GND
V+ Supply voltage (max 5volts)Supply voltage V+
3V33.3volt output (max 100mA) IO external supply (1.2-3.3volts) IO
IOIO external supplyPush button 18
19 16
20 14
21 13
22 12
23 8
27 6
28 5
29 3
30 2
31 1
32 44
33 43
34 42
36 41
37 40
38LED D2LED D1 39

PCB

Pcb-XC9572XL-CPLD-breakout-lv.jpg

We used the freeware version of Cadsoft Eagle to make the schematic and PCB. Download the latest board files from SVN.

Partslist

Board-XC9572XL-CPLD-breakout-iv.png

Click for a full size placement image.

partlist
Parts Quantity Value Package
C1,C2,C3,C4 4 0.1uF C603
C5,C6 2 3.3uF tantalum SMC_A
D1, D2, PWR 3 Yellow LED LED-805
JTAG 1 0.1” Pin header 1X06
PB 1 SMD button, small TACT_SWITCH_SMALL
R1 1 10K R603
R2,R3, R4 3 2K R603
VIO 1 0.1” Pin header M1X2
U1 1 XC9572XL_VQ44 VQ44
U2 1 3.3volt LDO voltage regulator 150mA SOT-23-5

The latest sources and distributors are in the master partlist. See something missing? Please let us know.


Q1 on the bottom of the PCB is for an optional 3.3volt oscillator. It feeds into a global clock pin. Some suitable values are:

Programming

Development and programming tutorials are on the main CPLD page.

Get one!

Xc9572-cpld-breakoutvib.jpg

Get one for $15 at Seeed Studio.

Your purchases keep the open source projects coming, we sincerely appreciate your support!

Resources

License

  • CC-BY-SA