The T80251XC3 core implements a compact 16-bit microcontroller that executes the MCS®251 & MCS®51 instruction sets and includes a configurable range of features and integrated peripherals.
The core’s advanced architectural design enables a high-performance 8051/80251-compatible MCU in a relatively small silicon footprint. The CPU itself (including the register files) is smaller than 13,000 gates, and can deliver 0.1455 DMIPS/MHz.
The T80251XC3 is extremely energy efficient, especially for applications that process 8- or 16-bit data. Its small footprint translates to very little power leakage, and its better performance than other 8-bit or 16-bit MCUs allows clocking at lower frequencies. Users can also adjust the core’s energy consumption to match the processing workload via dynamic frequency scaling and independent control of the CPU and peripherals clocks. Finally, the 80251 ISA’s complex addressing modes minimize the number of load/store operations, which typically comprise 20% or more of a RISC processor’s code. With denser code needing smaller firmware memory and fewer required memory accesses, the energy consumption of the MCU’s memory subsystem can be significantly less with the T80251XC3.
The core has a rich set of optional features and pre-integrated peripherals, allowing function, performance, and area to be balanced for each specific application. Software development is facilitated by a single-wire or JTAG debugging interface that operates seamlessly within the ARM® Keil® C251 integrated development environment. Inexpensive debug pods and a complete reference design board package are available.
This 80251 core 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 or asynchronous reset, and no internal tri-states.
- Fully compatible with the MCS®251 & MCS®51 instruction sets
- Small Silicon Footprint
- CPU is below 13k gates on 180nm
- Smaller memory footprint, due to denser code for 8- and 16-bit data processing
- ISA Addressing modes minimize load/store operation typically comprising 20%-25% with RISC CPUs
- Energy Efficient
- Low leakage and static CPU power on the CPU, due to small silicon footprint
- Low energy for instruction and data transfers and storage due to addressing modes that minimizes the need for load/store operations
- Advanced power management supports dynamic frequency scaling and CPU and/or peripherals clock gating
- 0.1455 DMIPS/MHz for a 15.48x speed-up over the original 8051 at the same clock frequency
- Hundreds of times faster than the original 8051 when clocked at maximum frequency
- Configurable Microcontroller
- Automatic instantiation of user selectable MCU peripherals
- Pre-integration with other CAST IP on request
- Easy Firmware Development
- CDP-XC on-chip debug interface, supports JTAG and Single-Wire
- USB-to-Serial and USB-JTAG, low cost CDP-XC debug pods
- Seamless integration with Keil µVisionTM
- Flexible Memory Architecture
- 16MB program and data address space; 64kB stack space
- Acknowledged transactions feature makes integration with slow memoires or peripherals easy
- 14x32-bit general purpose registers
- Up to 23 interrupts, with two or four interrupt priority levels
- The core is available in Verilog RTL or as a targeted FPGA netlist. Its deliverables include everything required for a successful implementation, including a behavioral model, an automated constrained random verification (CRV) testbench, comprehensive documentation, and sample synthesis and simulation scripts.
- The T80251XC3 is a low-power and relatively inexpensive processor that can be used for a variety of tasks, for example as a peripheral microcontroller in complex SoCs, a sensor subsystem MCU in IoT applications, or an embedded processor in mixed-signal ICs.
Block Diagram of the Tiny, Configurable, 16-bit 80251 Microcontroller