Complex Programmable Logic Devices

EE 365

PLDs16V8 (20 Pins)

• can have 16 inputs (max) and/or 8 outputs (marcrocells)• has 32 inputs to each of the AND gates (product terms)

22V10 (24 pins)

• can have 22 inputs and/or 10 outputs (max)• has 44 inputs to each of the AND gates How about a “128V64” for larger applications? It will be slower and will more wasted silicon space

Solution? Use CPLDs

GAL16V8(review seq_1.ppt)

• Each output is programmable as combinational or registered

• Also has programmable output polarity

And PlaneAnd Plane

The OR gatesThe OR gates

XOR gates tomake inverting or

non-inverting buffer

XOR gates tomake inverting or

non-inverting buffer

A General CPLD structure

A collection of PLDs on a single chip withProgrammble interconnects

Who makes the CPLDs?

Manufacturer CPLD Products URL

Altera MAX 5000, 7000 & 9000 www.altera.com Altmel ATF & ATV www.atmel.com Cypress FLASH370, Ultra37000 www.cypress.com Lattice ispLSI 1000 to 8000 www.latticesemi.com Philips XPLA www.philips.com Vantis MACH 1 to 5 www.vantis.com Xilinx XC9500 www.xilinx.com

Manufacturer CPLD Products URL

Altera MAX 5000, 7000 & 9000 www.altera.com Altmel ATF & ATV www.atmel.com Cypress FLASH370, Ultra37000 www.cypress.com Lattice ispLSI 1000 to 8000 www.latticesemi.com Philips XPLA www.philips.com Vantis MACH 1 to 5 www.vantis.com Xilinx XC9500 www.xilinx.com

Let’s takes a look at thisLet’s takes a look at this

The Xilinx 9500-series CPLD

• The internal PLDs are called Configurable Functional Blocks (FBs or CFBs)

• Each FB has 36 inputs and 18 Macrocells (effectively a “36V18”)

• Each CLPD is packaged in a plastic-leaded chip carrier (PLCC)

• The number of I/O pins are much less than the total number of Macrocells in family of devices

Xinlinx CPLDs

Architecture of Xilinx 9500-family CPLD

Global set/resetGlobal set/reset

Global 3 state controlGlobal 3 state control

Global ClockGlobal Clock

36 Signal pins36 Signal pins

18 outputs18 outputs

18 Outputenable signals

18 Outputenable signals

Architecture of Xilinx FB

Most CLPDs have fewer AND terms per macrocellXC9500 has 5 whereas 16V8 has 8 and 22V10 has 8-16

But…each macrocell can use unused ANDs froms its neigboring macrocells using the “product-term-allocators”

XC9500 Productterm allocator and

macrocell

XC9500 Productterm allocator and

macrocell

ISPISP

XC9500 I/O BlockXC9500 I/O Block

1

• Could be anything from a limited set of multiplexers to a full crossbar.

• Multiplexer -- small, fast, but difficult fitting

• Crossbar -- easy fitting but large and slow

Switch matrix for XC95108

XC4000E I/O Block