Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

1.2.1 CPU32

The CPU32 is an M68000 family processor specially designed for use as a 32-bit core processor and for operation over the intermodule bus (IMB). Designers used the MC68020 as a model and included advances of the later M68000 family processors, resulting in an instruction execution performance of 4 MIPS (VAX-equivalent) at 25.16 MHz.

The powerful and flexible M68000 architecture is the basis of the CPU32. MC68000 (including the MC68HC000 and the MC68EC000) and MC68010 user programs will run unmodified on the CPU32. The programmer can use any of the eight 32-bit data registers for fast manipulation of data and any of the eight 32-bit address registers for indexing data in memory. The CPU32 can operate on data types of single bits, binary-coded decimal (BCD) digits, and 8, 16, and 32 bits. Peripherals and data in memory can reside anywhere in the 4-Gbyte linear address space. A supervisor operating mode protects system-level resources from the more restricted user mode, allowing a true virtual environment to be developed.

Flexible instructions for data movement, arithmetic functions, logical operations, shifts and rotates, bit set and clear, conditional and unconditional program branches, and overall system control are supported, including a fast 32 ⋅ 32 multiply and 32-bit conditional branches. New instructions, such as table lookup and interpolate and low power stop, support the specific requirements of embedded control applications. Many addressing modes complement these instructions, including predecrement and postincrement, which allow simple stack and queue maintenance and scaled indexed for efficient table accesses. Data types and addressing modes are supported orthogonally by all data operations and with all appropriate addressing modes. Position-independent code is easily written.

The CPU32 is specially optimized to run with the MC68340's 16-bit data bus. Most instructions execute in one-half the number of clocks compared to the original MC68000, yielding an overall 1.6 times the performance of the same-speed MC68000 and measuring 10,045 Dhrystones/sec @ 25.16 MHz (6,742 Dhrystones/sec @ 16.78 MHz).

Like all M68000 family processors, the CPU32 recognizes interrupts of seven different priority levels and allows the peripheral to vector the processor to the desired service routine. Internal trap exceptions ensure proper instruction execution with good addresses and data, allow operating system intervention in special situations, and permit instruction tracing. Hardware signals can either terminate or rerun bad memory accesses before instructions process data incorrectly.

The CPU32 offers the programmer full 32-bit data processing performance with complete M68000 compatibility, yet with more compact code than is available with RISC processors. The CPU32 is identical in all CPU32-based M68300 family products.

1.2.2 Background Debug Mode

A special operating mode is available in the CPU32 in which normal instruction execution is suspended while special on-chip microcode performs the functions of a debugger.

1- 4MC68340 USER’S MANUALMOTOROLA

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Motorola MC68340 manual Freescale Semiconductor, Inc 1 CPU32, Background Debug Mode
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MC68340 specifications

The Motorola MC68340 is a highly integrated microprocessor that was introduced in the early 1990s. It belongs to the 68000 family of microprocessors and is designed to cater to the demands of embedded systems, particularly in telecommunications and networking applications. This chip represents a significant evolution in microprocessor technology by combining a microprocessor core with additional peripherals on a single chip, making it an attractive solution for engineers looking to design compact and efficient systems.

One of the key features of the MC68340 is its 32-bit architecture, which allows for significant processing power and data handling capabilities. This architecture enables the processor to handle larger data sizes and perform more complex calculations compared to its 16-bit predecessors. The MC68340 operates at clock speeds typically ranging from 16 MHz to 25 MHz. Its dual instruction pipeline enhances throughput, allowing for simultaneous instruction fetches and executions, which significantly boosts performance.

A notable characteristic of the MC68340 is the inclusion of integrated peripherals, which help reduce the overall component count in a system. Key integrated components include a memory management unit (MMU), a direct memory access (DMA) controller, and various communication interfaces such as serial ports. The memory management capabilities enhance the processor's ability to manage memory resources efficiently, enabling it to support multitasking environments commonly found in modern computing.

In terms of connectivity, the MC68340 features connections for both synchronous and asynchronous serial communication, making it well-suited for networking tasks. The processor supports a range of bus standards, including address and data buses, which facilitate seamless interaction with peripheral devices.

Another important aspect of the MC68340 is its flexibility. The processor supports multiple operating modes, including multiple CPU configurations and compatibility with the Motorola 68000 family, allowing for easier integration into existing systems.

Moreover, the MC68340 boasts low power consumption compared to many of its contemporaries, making it an excellent choice for battery-operated applications, enhancing its appeal in sectors like telecommunications, industrial control, and automotive systems. Its combination of performance, integration, versatility, and efficiency has secured the MC68340 a reputable position in the annals of embedded systems technology, proving to be a valuable asset for developers and engineers alike.
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