Interrupt Request Level IRQ7, IRQ6, IRQ5, IRQ3

Freescale Semiconductor, Inc...

Freescale Semiconductor, Inc.

Port B4, B2, B1, AVEC

This signal group functions as three bits of parallel I/O and the autovector input. AVEC requests an automatic vector during an interrupt acknowledge cycle.

2.6 INTERRUPT REQUEST LEVEL (IRQ7, IRQ6, IRQ5, IRQ3)

These pins can be programmed to be either prioritized interrupt request lines or port B parallel I/O.

IRQ7, IRQ6, IRQ5, IRQ3

IRQ7, the highest priority, is nonmaskable. IRQ6–IRQ1are internally maskable interrupts. Refer to Section 5 CPU32 for more information on interrupt request lines.

Port B7, B6, B5, B3

These pins can be used as port B parallel I/O. Refer to Section 4 System Integration Module for more information on parallel I/O signals.

2.7 BUS CONTROL SIGNALS

These signals control the bus transfer operations of the MC68340. Refer to Section 3 Bus Operation for more information on these signals.

2.7.1 Data and Size Acknowledge (DSACK1, DSACK0)

These two active-low input signals allow asynchronous data transfers and dynamic data bus sizing between the MC68340 and external devices as listed in Table 2-3. During bus cycles, external devices assert DSACK1 and/or DSACK0 as part of the bus protocol. During a read cycle, this signals the MC68340 to terminate the bus cycle and to latch the data. During a write cycle, this indicates that the external device has successfully stored the data and that the cycle may terminate.

Table 2-3. DSACK≈ Encoding

DSACK	DSACK	Result
1	0
1	1	Insert Wait States in Current Bus Cycle
1	0	Complete Cycle—Data Bus Port Size Is 8 Bits
0	1	Complete Cycle—Data Bus Port Size Is 16 Bits

00 Reserved—Defaults to 16-Bit Port Size Can Be Used for 32-Bit DMA Cycles

2.7.2Address Strobe (AS)

AS is an output timing signal that indicates the validity of both an address on the address bus and many control signals. AS is asserted approximately one-half clock cycle after the beginning of a bus cycle.

2- 6MC68340 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.

Motorola MC68340 manual Interrupt Request Level IRQ7, IRQ6, IRQ5, IRQ3, BUS Control Signals

Models: MC68340