System Configuration and Protection Registers

Freescale Semiconductor, Inc.

NOTE

An access to this register does not affect external space since the cycle is not run externally.

Example code for accessing the MBAR is as follows:

MOVE.L	#7,D0	load D0 with the CPU space function code
MOVEC.L	D0,SFC	load SFC to indicate CPU space
LEA.L	$0003FF00,A0	load A0 with the address of MBAR
MOVES.L	(A0),D0	load D0 with the contents of MBAR

Address $0003FF00 in CPU space (MBAR) will be loaded with the value $FFFFF001. This value will set the base address of the internal registers to $FFFFF. MBAR can be written to using the following code:

MOVE.L	#7,D0	load D0 with the CPU space function code
MOVEC.L	D0,DFC	load DFC to indicate CPU space
LEA.L	$0003FF00,A0	load A0 with the address of MBAR
MOVE.L	#$FFFFF001,D0	load D0 with the value to be written into MBAR
MOVES.L	D0,(A0)	write the value contained in D0 into MBAR

4.3.2 System Configuration and Protection Registers

The following paragraphs provide descriptions of the system configuration and protection registers.

4.3.2.1MODULE CONFIGURATION REGISTER (MCR). The MCR, which controls the SIM40 configuration, can be read or written at any time.

MCR															$000
15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
0	FRZ1	FRZ0	FIRQ	0	0	SHEN1	SHEN0	SUPV	0	0	0	IARB3	IARB2	IARB1	IARB0
RESET:
0	1	1	0	0	0	0	0	1	0	0	0	1	1	1	1

Supervisor Only

Bits 15, 11, 10, 6–4—Reserved

FRZ1—Freeze Software Enable

1 = When FREEZE is asserted, the software watchdog and periodic interrupt timer counters are disabled, preventing interrupts from occurring during software debug.

0 = When FREEZE is asserted, the software watchdog and periodic interrupt timer counters continue to run. See 4.2.7 Freeze for more information.

MOTOROLAMC68340 USER’S MANUAL4- 21

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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 System Configuration and Protection Registers, Mcr

Models: MC68340

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

4.3.2 System Configuration and Protection Registers

MCR

MC68340 specifications