Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

load capacitance on the chip-select (CS≈) signal is not exceeded. (Address buffers may be needed, however.)

10.1.4 ROM Interface

Using the programmable chip selects creates a very straightforward ROM interface. As shown in Figure 10-6, no external circuitry is needed. Care must be used, however, not to overload the address bus. Address buffers may be required to ensure that the total system input capacitance on the address signals does not exceed the CL specification.

MC68340

 

A16–A1

 

D15–D0

16-BIT

ROM

CS0

CE

 

CE

 

 

Figure 10-6. ROM Interface

10.1.5 Serial Interface

The necessary circuitry to create an RS-232 interface with the MC68340 includes an external crystal and an RS-232 receiver/driver (see Figure 10-7). The resistor and capacitor values shown are typical; the crystal manufacturer's documentation should be consulted for specific recommendations on external component values. The circuit shown does not include modem support (ready-to-send (RTS) and clear-to-send (CTS) are not shown); however, these signals can be connected to the receiver/driver and to the connector in a similar manner as the connections for TxDx and RxDx.

10-4MC68340 USER’S MANUALMOTOROLA

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Motorola MC68340 manual ROM Interface, Serial Interface
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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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