Motorola MC68340 manual OP0 OP1 Data BUS

Models: MC68340

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Freescale Semiconductor, Inc...

Freescale Semiconductor, Inc.

3.2.3.3BYTE OPERAND TO 16-BIT PORT, ODD (A0 = 1). The MC68340 drives the address bus with the desired address and the SIZx pins to indicate a single-byte operand.

BYTE OPERAND

 

 

 

OP0

 

 

 

 

 

 

 

 

7

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DATA BUS

D15

D8 D7

 

D0

SIZ1

SIZ0

A0

DSACK1

DSACK0

CYCLE 1

(OP0)

 

 

OP0

0

1

1

0

 

X

For a read operation, the slave responds by placing data on bits 7–0 of the data bus and asserting DSACK1 to indicate a 16-bit port. The MC68340 then reads the operand byte from bits 7–0 and ignores bits 15–8.

For a write operation, the MC68340 drives the single-byte operand on both bytes of the data bus because it does not know the port size until the DSACKsignals are read. The slave device reads the operand from bits 7–0 of the data bus and uses the address to place the operand in the specified location. The slave then asserts DSACK1 to terminate the bus cycle.

3.2.3.4WORD OPERAND TO 8-BIT PORT, ALIGNED. The MC68340 drives the address bus with the desired address and the SIZx pins to indicate a word operand.

WORD OPERAND

 

OP0

 

OP1

 

 

 

 

 

 

 

15

 

8

7

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DATA BUS

D15

 

D8

D7

D0

SIZ1

SIZ0

A0

DSACK1

DSACK0

CYCLE 1

 

OP0

 

(OP1)

1

0

0

1

 

0

CYCLE 2

 

OP1

 

(OP1)

0

1

1

1

 

0

For a read operation, the slave responds by placing the most significant byte of the operand on bits 15–8 of the data bus and asserting DSACK0 to indicate an 8-bit port. The MC68340 reads the most significant byte of the operand from bits 15–8 and ignores bits 7–0. The MC68340 then decrements the transfer size counter, increments the address, and reads the least significant byte of the operand from bits 15–8 of the data bus.

For a write operation, the MC68340 drives the word operand on bits 15–0 of the data bus. The slave device then reads the most significant byte of the operand from bits 15–8 of the data bus and asserts DSACK0 to indicate that it received the data but is an 8-bit port. The MC68340 then decrements the transfer size counter, increments the address, and writes the least significant byte of the operand to bits 15–8 of the data bus.

MOTOROLAMC68340 USER’S MANUAL3- 9

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Motorola MC68340 manual OP0 OP1 Data BUS

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.