Our family of microcontroller and microprocessor related cores includes capable and competitive 32-bit BA22s and the best-available set of proven 8051s.

32-bit Processors
BA2x Family Overview

Application Processors
BA25 Adv. App. Processor
BA22 Basic App. Processor

Cache-Enabled Embedded
BA22 Cache-Embedded

Embedded Processors
BA22 Deeply Embedded
BA21 Low Power
BA20 PipelineZero

Peripheral Platforms
& AMBA Infrastructure

BA2x AHB Platform
BA2x AXI Platform


GPUs & Peripherals
See Graphics &
  Peripherals Cores >

These video and image compression cores and subsystems help you handle video compression for demanding, high-quality applications or choose the best type of image compression for your specific system.

JPEG 2000
J2K Platform

Lossless Compression
LJPEG Encoder
LJPEG Decoder
JPEG-LS Encoder

Complement or replace system processors with GPUs and easily integrate memories, peripherals, and hardware networking stacks into SoCs.

Graphics Processors
Nema Embedded GPU
ThinkVG vector GPU
2D/2.5D Graphic Accelerator

Display Controllers
Multilayer LCD Display Processor

Device Controllers
smart card reader

Legacy Peripherals
DMA Controllers
8237, 82380
16450S, 16550S, 16750S

AMBA Infrastructure
AMBA Infrastructure Cores
AHB 32-bit DMA

Interconnect Peripherals

See Interconnect Cores >

Quickly complete the standard parts of your SoC with these memory and peripheral controllers, interfaces, and interconnect cores.

• Receiver

Ethernet MAC
• 1G eMAC Controller

Data Link Controllers

PCI — Target
32-bit multi
PCI — Master
32-bit multi
PCI — Host Bridge
32 bit
32 bit - AHB
32 bit & device - AHB

These encryption cores make it easy to build security into a variety of systems.

DES single
DES triple

  • Fully compatible with the MCS® 51 instruction set
  • Single clock per cycle and efficient architecture for up to 12.1 times the performance of original 8051
  • Fewer machine cycles means lower average power usage in most applications
  • Extensive set of optional features and peripherals: choose configurable or less-expensive fixed versions
  • Debugging option: On-Chip Debug Support (OCDS) block that interfaces through IEEE1149.1 (JTAG) port; external debugging pod with JTAG and single-wire SWAT; and debugging software with interface to Keil & IAR tools

Options and Peripherals

Full user-configurable version includes all of these; other versions include a subset (see Versions).

External Memory Interface:

  • Addresses up to 8 MB of Program and Data Memory each (when using memory banking)
  • One, two or eight Data Pointers for fast data block transfer
  • Additional Arithmetic Unit supports data pointers, auto-increment/-decrement, and auto-switch
  • Supports external DMA controller through HOLD function
  • Program memory write mode

Direct Memory Access (DMA) Controller:

  • Up to eight independent channels
  • Read/Write Access to all memory spaces (incl. SFR)
  • Linear addressing (up to 8MB)
  • Address auto-increment/decrement
  • Synchronous/asynchronous Mode
  • Software/Hardware Triggers

Multiplication-Division Unit:

  • 16 x 16-bit multiplication,
  • 32/16- and 16/16-bit division,
  • 32-bit normalization and L/R shifting

Special Function Registers Interface:

  • services from 36 to 119 external SFRs

Interrupt Controller:

  • Four priority levels with eighteen interrupt sources, or
  • Two priority levels with six sources

Input/Output Interfaces

  • Parallel Ports: up to six 8-bit Input/Output ports
  • Serial 0 interface:
    • Full-duplex serial interface (80C51-like),
    • Equipped with an additional baud rate generator
  • Serial 1 interface:
    • an asynchronous-only version of Serial 0
  • SPI Master/Slave interface
  • I2C™ Master/Slave interfaces: one or two

Timers and Counters

  • 16-bit Timers/Counters:
    • Timers 0 and 1: 80C51-like simple timers
    • Timer 2: 80C515-like, operates as timer, event counter or gated timer
  • Watchdog Timer: 15-bit programmable

Power Management Unit with power-down modes (IDLE/STOP)


  • all versions include sophisticated self-checking Testbench (Verilog versions use Verilog 2001) with CPU behavioral model, memory models, and more.

Contact Sales
Call or click.
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PDF Datasheets

Altera, Xilinx

Related Products

The 8051 family also includes:


  • L8051XC1 Legacy-Configurable 8051-Compatible Microcontroller IP Core
  • S8051XC3 Super-Fast 8051 Microcontroller Core with Configurable Features and Peripherals
  • T8051XC3 Ultra-Small 8051-Compatible Microcontroller IP Core

Options for this Core

Several versions of this 8051 core are available; see below.

A native on-chip debug package with external adapter (pod) is available for JTAG or single-wire SWAT debugging, with support for Keil and IAR tools.

Try It Yourself

evaluate CAST 32-bit processor IP cores with the Talos Eval KitEvaluate the R8051XC2's features and performance in your own environment with the Talos Series Evalation Kit.

Related Information

News Releases


Understanding Interrupt Latency in Modern 8051s by Nikos Zervas at ChipEstimate.com

CAST Announces World's Fastest 8051-Compatible MCU Core by Max Maxfield, EE Times

CAST’s 8051 IP core is going strong
Article by Clive Maxwell, EE Times

Using 8-bit 8051s in a 32-bit World
Article by Bill FInch, in Extension Media's Engineers' Guide to 8/16-bit Technologies

Blog Posts

Third-Party Tools

The R8051XC2 is supported by leading development and debug tools, including:


IAR supports CAST S8051XC3 core  IAR Embedded Workbench



Keil supports CAST S8051XC3 core  Keil 8051 Development Tools


Develop software for this 8051 core with the ARM® Keil™ µVision4 Integrated Development Environment

"The µVision®4 IDE builds on the success of what is widely acknowledged as the most popular development environment for microcontrollers," said Mark Onions, Director of Marketing, System Design Division at ARM. "Now, with support for the R8051XC2 processor, developers using the 8051 architectures can benefit from faster hardware and software development and verification." 8/10/09

R8051XC2 High-Performance, Configurable, 8051-Compatible, 8-bit Microcontroller Core

This 8051 IP core implements a range of fast, 8-bit, 8051-compatible microcontrollers that execute the MCS®51 instruction set.

The R8051XC2 IP core runs with a single clock per machine cycle, and requires an average of 2.12 machine cycles per instruction. Dhrystone 2.1 tests show it to run from 9.4 to 12.1 times faster than the original 8051 at the same frequency. Representative 90 nm ASIC results have reached 430 MHz, for an effective speed-up of 400 times over 80C51 chips.

The configurable core has a rich set of optional features and peripherals. Designers can choose from several versions, including the easy-to-configure full version with all options included; a custom, non-configurable version with options specified at purchase; and pre-packaged versions with different sets of options and degrees of configurability.

All versions of this 8051 core benefit from power-saving architectural efficiency—the R8051XC2 is 10% better in milliwats/DMIP than our previous generation—and various power-management options are available. System development is facilitated through a native on-chip debugging option and support by development tools from Keil and IAR.

This product builds on CAST’s experience with hundreds of 8051 IP customers going back to 1997. Designed for easy reuse in ASICs, structured ASICs, or FPGAs, the core is strictly synchronous, with positive-edge clocking (except in the optional debug & SPI modules), synchronous reset, and no internal tri-states. Representative 90nm ASIC results show the core to be conservative in its use of space, requiring just 8,000 to 71,000 gates.

See representative implementation results (in a new pop-up window):

ASIC numbers Xilinx numbers


The 8051 continues to be a rigorous and cost-effective solution for many applications, and the fast, flexible R8051XC2 is an especially good choice for many systems. Popular uses include data management control for complex systems, and interface control for analog and sensing chips.


The core as delivered is warranted against defects for ninety days from purchase. Thirty days of phone and email technical support are included, starting with the first interaction. Additional maintenance and support options are available; contact CAST Sales.


The core has been verified through extensive simulation and rigorous code coverage measurements. All subcomponents were functionally verified with an HDL testbench using their individual test suites. The CPU and ALU have been verified against a proprietary hardware modeler and behavioral models. The peripherals have also been verified in their own testbenches, based on either hardware or behavioral models. An extensive constrained random verification was performed to verify the CPU, DMA and OCDS.


The core is available in ASIC (synthesizable HDL) and FPGA (netlist) forms, and includes everything required for successful implementation:

A reference design board is available; contact CAST Sales for information.

Available Versions

Three versions of this 8051 core are available, offering a range of capabilities and prices. (See block diagrams below.)

R8051XC2-F includes the full set of options, and is user-configurable (i.e., options may be included or excluded prior to synthesis).

R8051XC2-A includes options that match the original Intel 8051 peripheral set: 64kB memory interface, two timers, one serial port, four parallel I/O Ports, two-level interrupt controller, and two DPTR registers. These options are user-configurable (i.e., may be deleted prior to synthesis).

R8051XC2-B includes options that match the Infineon 80515/80517 peripheral set: 64kB memory interface, three timers, two serial ports, four parallel I/O ports, watchdog timer, multiplication-division unit, and two DPTR registers. These options are user-configurable (i.e., may be deleted prior to synthesis).

ASIC (RTL) and FPGA (netlist) deliverables are available; FPGA packages are not user-configurable.



Block Diagrams for Standard Versions

R8051XC2-F Block Diagram

r8015xc2 block diagram

R8051XC2-A Block Diagram

r8015xc2 block diagram

R8051XC2-B Block Diagram

r8015xc2 block diagram

Comparing 8051 Cores



Fast, Mature




DMIPS/MHz vs Original 80C51

1x or 2.1x




8x8 Multiply (Cycles)

24 or 12



1 or 2

16x16 Multiply w/o MDU (Cycles) 50 50 67 32

16x16 Multiply with MDU (Cycles)





32-bit Code/Data Bus

not supported

not supported

not supported


DPTR Arithmetic Acceleration





Advanced Execution Architecture

not supported

not supported

not supported



Program/Data Address Space

64K Bytes

64KB or 8MB

64K Bytes

64KB or 8MB

Configurable Set of Peripherals





24-bit DPTR

not supported

not supported

not supported

not supported

Optional Extra 16-bit DPTRs

1 to 7

1 to 7

0 to 1

0 to 1

32-bit Code/Data Bus

not supported

not supported

not supported


Separate XDATA Bus

not supported

not supported

not supported


Peripherals: 80C51-Like

TIMER 0 — 16-bit Counter/Timer





TIMER 1 — 16-bit Counter/Timer





SERIAL — Full duplex sync/async serial port





GPIO 0 — 8-bit Paralell Port included included included included
GPIO 1-3 — 8-bit Paralell Ports included included optional included
ISR — Interrupt Controller: 6 sources and 2 priority levels included included included included

Peripherals: SAB80C515-Like

TIMER 2 — 16-bit Counter/ Timer/ Event Counter & Capture Compare Unit included included not supported not supported
WDT — 15-bit Watchdog timer included included not supported not supported
MDU — 32-bit Multiplication Division Unit included included optional optional
ISR — Interrupt Controller: 18 sources and 4 priority levels included included not supported not supported
GPIO 4,5,6 — 8-bit Parallel Ports included included optional optional
SERIAL 0 — Full duplex sync/async serial port included included optional optional
SERIAL 1 — Full duplex sync/async serial port included included optional optional

Peripherals: Dallas 80C530-Like

RTC — Real time clock optional included optional optional

Peripherals: 8025-Like

TIMER 2 — 16-bit Timer not supported not supported optional included
WDT — 14-bit Watchdog timer optional not supported optional included
PCA — Programmable Counter Array: Fice 16-bit PWM channels optional not supported optional included

Peripherals: Proprietary

MAC — 40-bit Multiply Accumulator Unit not supported not supported not supported included
PMU/DFS — Power Mgmt Unit with Dynamic Frequency Scaling not supported not supported optional included
PMU — Power Mgmt Unit included included included not supported
I2C 0, 1 — I2C Master/Slave with SMBUS extension included included optional included
SPI_MS — SPI Master/Slave included included optional included
DMA — DMA Controller optional included not supported optional
OCDS — On Chip Debug Support (JTAG and Single-Wire) included included included included
XWDT — Extended Watchdog Timer not supported optional not supported not supported
ISR — Interrupt Controller: 23 sources and 4 priority levels not supported not supported optional included
CAN — CAN Bus Controller optional optional optional optional
LIN — LIN Bus Controller optional optional optional optional
LCD — LCD/TFT Display Controller optional optional optional optional

included= Included or user-configurable option  optional= On request  not supported= Not supported


1. Performance data correspond to maximum performance configuration, compared to 0.00941 DMIPS/MHz of the original 80C51