Motorola MC68340 manual DMA Channel Example Configuration Code, DMACH1 EQU, DMAMCR1 EQU

Models: MC68340

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Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

If using internal request, select the amount of bus bandwidth to be used by the DMA (BB field).

Clear the S/D bit for dual-address transfer.

Channel Status Register (CSR)

Clear the CSR by writing $7C into it. The DMA cannot be started until the DONE, BES, BED, CONF, and BRKP bits are cleared.

Function Code Register (FCR)

• Encode the source and destination function codes.

Address Registers (SAR and DAR)

• Write the source and destination addresses.

Byte Transfer Counter (BTC)

• Encode the number of bytes to be transferred.

Channel Control Register (CCR)

• Write a one to the start bit (STR) to allow the transfer to begin.

6.9.2 DMA Channel Example Configuration Code

The following are examples of configuration sequences for a DMA channel in single- and dual-addressing modes.

***************************************************************************

*MC68340 basic DMA channel register initialization example code.

*This code is used to initialize the 68340's internal DMA channel

*registers, providing basic functions for operation.

*The code sets up channel 1 for external burst request generation,

*single-address mode, long word size transfers.

*Control signals are asserted on the DMA read cycle.

***************************************************************************

Example 1: External Burst Request Generation, Single-Address Transfers.

***************************************************************************

*SIM40 equates

***************************************************************************

MBAR

EQU

$0003FF00

Address of SIM40 Module Base Address Reg.

MODBASE

EQU

$FFFFF000

SIM40 MBAR address value

 

***************************************************************************

 

* DMA Channel 1 equates

 

 

DMACH1

EQU

$780

Offset from MBAR for channel 1 regs

 

DMAMCR1

EQU

$0

MCR for channel 1

 

* Channel 1 register offsets from channel 1 base address

 

6- 38

 

 

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Motorola MC68340 manual DMA Channel Example Configuration Code, DMACH1 EQU, DMAMCR1 EQU

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.