Reset Circuitry, Sram Interface | Motorola MC68340 manual

Semiconductor, Inc.

Freescale Semiconductor, Inc.

	VCCSYN
VCCSYN
MC68340	0.1 ∝F 1	0.1 ∝F	0.01 ∝F
XFC

NOTE 1: Must be a low-leakage capacitor.

Figure 10-4. XFC and V CCSYN Capacitor Connections

10.1.2 Reset Circuitry

Because it is optional, reset circuitry is not shown in Figure 10-1. The MC68340 holds itself in reset after power-up and asserts RESET to the rest of the system. If an external reset pushbutton switch is desired, an external reset circuit is easily constructed by using open-collector cross-coupled NAND gates to debounce the output from the switch.

10.1.3 SRAM Interface

The SRAM interface is very simple when the programmable chip selects are used. External circuitry to decode address information and circuitry to return data and size acknowledge (DSACK≈) is not required. However, external ICs are required to provide write enables for the high and low bytes of data.

Freescale

A15-A1	SIZ0
	A0	UWE	.
	AS	...	.
		...
		MCM6206-35
MC68340		R/W
		LWE
		CE
		E

...	.		...	.		..	.	.

		MCM6206-35
			R/W
			CE
	..		E		.		. .
.

R/W

D15-D0 CS

D7-D0

.		.
	D15-D8

Figure 10-5. SRAM Interface

The SRAM interface shown in Figure 10-5 is a two-clock interface at 16.78-MHz operating frequency. The MCM6206C-35 memories provide an access time of 15 ns when the chip enable (E) input is low. If buffers are required to reduce signal loading or if slower and less expensive memories are desired, a three-clock cycle can be used. In the circuit shown in Figure 10-5, additional memories can be used provided the MC68340 specification for

MOTOROLAMC68340 USER’S MANUAL10-3

For More Information On This Product,

Go to: www.freescale.com

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 Reset Circuitry, Sram Interface

Models: MC68340