Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

Internal Bus Monitor

The SIM40 provides an internal bus monitor to monitor the DSACK≈ response time for all internal bus accesses. An option allows the monitoring of external bus accesses. For external bus accesses, four selectable response times are provided to allow for variations in response speed of memory and peripherals used in the system. A bus error signal is asserted internally if the DSACK≈ response limit is exceeded. BERR is not asserted externally. This monitor can be disabled for external bus cycles only.

Double Bus Fault Monitor

The double bus fault monitor causes a reset to occur if the internal HALT is asserted by the CPU32, indicating a double bus fault. A double bus fault results when a bus or address error occurs during the exception processing sequence for a previous bus or address error, a reset, or while the CPU32 is loading information from a bus error stack frame during an RTE instruction. This function can be disabled. See Section 3 Bus Operation for more information.

Spurious Interrupt Monitor

If no interrupt arbitration occurs during an interrupt acknowledge (IACK) cycle, the bus error signal is asserted internally. This function cannot be disabled.

Software Watchdog

The software watchdog asserts reset or a level 7 interrupt (as selected by the system protection and control register) if the software fails to service the software watchdog for a designated period of time (i.e., because it is trapped in a loop or lost). There are eight selectable timeout periods. This function can be disabled.

Periodic Interrupt Timer

The SIM40 provides a timer to generate periodic interrupts. The periodic interrupt time period can vary from 122 ∝s to 15.94 s (with a 32.768-kHz crystal used to generate the system clock). This function can be disabled.

Figure 4-2 shows a block diagram of the system configuration and protection function.

4- 4MC68340 USER’S MANUALMOTOROLA

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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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