Memory Interface Information | Motorola MC68340 specification

Freescale Semiconductor, Inc.

Inc.

15 pF

	3.6864 MHz
X2
MC68340	5 pF
MC68340

RxDx		R
TxDx	T
	MC145407
10 ∝F	C1+	C2+
10 ∝F	C1-	C1-
	C1-	C1-
10 ∝ F	VSS	C2+
10 ∝ F	GND	C2-
	GND	C2-

Rx1

Tx1

VCC

10 ∝F

10 ∝ F

RS 232 CONNECTOR

Freescale Semiconductor,

Figure 10-7. Serial Interface

10.2 MEMORY INTERFACE INFORMATION

The following paragraphs contain information on using an 8-bit boot ROM, performing access time calculations, calculating frequency-adjusted outputs, and interfacing an 8-bit device to 16-bit memory using the DMA channel single-address mode.

10.2.1 Using an 8-Bit Boot ROM

Upon power-up, the MC68340 uses CS0 to begin operation. CS0 is a three-wait-state, 16- bit chip select, until otherwise programmed. If an 8-bit ROM is desired, external circuitry can be added to return an 8-bit DSACK≈ in two wait states (see Figure 10-8).

		'393
CLKOUT	CP	Q0
		Q1	DSACK0
		Q2
CS0	MR	Q3

Figure 10-8. External Circuitry for 8-Bit Boot ROM

The `393 is a falling edge-triggered counter; thus, CS0 is stable during the time in which it is being clocked. CS0 acts as the asynchronous reset—i.e., when it is asserted, the `393 is allowed to count. The falling edge of S2 provides the first counting edge. Q1 does not transition on this falling edge, but transitions to a logic one on the subsequent edge. DSACK0 is Q1 inverted; thus, on the next falling edge, DSACK0 is seen as asserted, indicating an 8-bit port. When CS0 is negated, Q1 is again held in reset and DSACK0 is negated. The timing diagram in Figure 10-9 illustrates this operation.

MOTOROLAMC68340 USER’S MANUAL10-5

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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.

Motorola MC68340 manual Memory Interface Information, Using an 8-Bit Boot ROM

Models: MC68340