What is the Difference Between CPLD and FPGA

The main difference between CPLD and FPGA is that the FPGA provides more logic resources and storage elements than CPLD.

An electronic circuit is a structure that consists of electronic components such as resistors, transistor, etc. Wires or traces help to connect all these components. An electric current passes through the components in an electric circuit. Two technologies that we can use to build electronic circuits are CPLD and FPGA.

Key Areas Covered

1. What is CPLD
     – Definition, Features
2. What is FPGA
     – Definition, Features
3. What is the Difference Between CPLD and FPGA
     – Comparison of Key Differences

Key Terms

CPLD, Electronic Circuits, FPGA

What is CPLD

CPLD stands for Complex Programmable Logic Devices. It is an integrated circuit that helps to implement digital systems. CPLD consist of a set of programmable functional blocks. There are macrocells in each block. Macrocells are the main building blocks of the CPLD. The inputs and outputs of functional blocks are connected via Global Interconnection Matrix (GIM). This interconnection matrix is reconfigurable so, it is not possible to change the contacts among the functional blocks. These functional blocks are similar to an array of logic gates.

When designing CPLDs, it is important to pay attention to programming technology, I/P capability, and functional block capabilities. Overall, CPLDs are nonvolatile and easy to use. Moreover, they are cost-effective.

What is FPGA

FPGA stands for Field Programmable Gate Array. It is a semiconductor device that consists of a matrix of configurable logic blocks connected using programmable interconnects. It is possible to reprogram an FPGA according to the requirements after manufacturing. There are around 330000 logic blocks with 1100 inputs and outputs in modern FPGAs.

Users can design the circuit using Hardware Description Language and configure that circuit to perform a simple gate such as an AND gate or a complex system such as a multi-core processor. It stores all the configurations in the RAM. Therefore, a power failure can erase these configurations.

The major components of FPGA are as follows.

Programmable Logic Blocks – It allows implementing logic functions.

Programmable Routing (interconnects) – It allows implementing functions.

IO blocks – It is used to make of chip connections.

Difference Between CPLD and FPGA

Definition

CPLD is an integrated circuit that helps to implement digital systems whereas FPGA is an integrated circuit designed to be configured by a customer or a designer after manufacturing. These definitions explain the main difference between CPLD and FPGA.

Long Form

CPLD stands for Complex Programmable Logic Device while FPGA stands for Field Programmable Gate Array.

Logic Resources

Logic resources is also a major difference between CPLD and FPGA. CPLD provides minimum logic resources while FPGA provides a massive amount of logic resources and storage elements to create complex systems.

Cost

Moreover, CPLDs are cost-effective, but FPGAs are expensive than CPLDs.

Blocks

Also, CPLDs are made up of larger blocks while FPGAs are made up of tiny logic blocks.

Memory

Another difference between CPLD and FPGA is their memory. CPLD uses EEPROM (nonvolatile) while FPGA uses RAM (volatile).

Delays

Besides, it is easier to predict the delays in CPLD than in FPGA.

Power Consumption

Furthermore, power consumption is also a difference between CPLD and FPGA. CPLD consumes low power while FPGA consumes more power.

Security

Security is another difference between CPLD and FPGA. CPLD is more secure than FPGA because it has a built-in nonvolatile memory.

Applications

Finally, CPLD is suitable for small to medium scale applications whereas FPGA is suitable for complex applications.

Conclusion

CPLD and FPGA are used to implement electronic devices. The main difference between CPLD and FPGA is that FPGA provides more logic resources and storage elements than CPLD.

Reference:

1. “Complex Programmable Logic Device.” Wikipedia, Wikimedia Foundation, 4 Oct. 2018, Available here.
2. “Field-Programmable Gate Array.” Wikipedia, Wikimedia Foundation, 19 Jan. 2019, Available here.
3. “Applications of Complex Programmable Logic Device (CPLD).” ElProCus – Electronic Projects for Engineering Students, 30 Sept. 2016, Available here.
4. “Field Programmable Gate Array (FPGA).” FPGA Design Flow Overview, Available here.
5. Agarwal, Tarun, et al. “Home.” Buy Electronics & Electrical Projects in India, 13 Nov. 2017, Available here.

Image Courtesy:

1. “XC9500XL CPLD breakout board” by Dangerous Prototypes (CC BY-SA 2.0) via Flickr
2. “Fpga xilinx spartan” By Dake – Dake (CC BY-SA 3.0) via Commons Wikimedia