MCR1, MCR2, FRZx Control Bits, Action | Motorola MC68340 guide

Freescale Semiconductor, Inc.

MCR1, MCR2														$780, $7A0
15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
STP	FRZ1	FRZ0	SE	0		ISM		SUPV		MAID				IARB
RESET:
0	0	0	0	0	0	0	0	1	0	0	0	0	0	0	0

Supervisor Only

STP—Stop Bit

1 = Setting the STP bit stops all clocks within the DMA module except for the clock from the IMB. The clock from the IMB remains active to allow the CPU32 access to the MCR. The clock stops on the low phase of the clock and remains stopped until the STP bit is cleared by the CPU32 or a hardware reset. Accesses to DMA module registers while in stop mode produce a bus error. The DMA module should be disabled in a known state before setting the STP bit. The STP bit should be set prior to executing the LPSTOP instruction to reduce overall power consumption.

0 = The channel operates in normal mode.

NOTE

The DMA module uses only one STP bit for both channels. A read or write to either MCR accesses the same STP control bit.

FRZ1, FRZ0—Freeze

These bits determine the action taken when the FREEZE signal is asserted on the IMB when the CPU32 has entered background debug mode. The DMA module negates BR and keeps it negated until FREEZE is negated or reset. Table 6-1 lists the action taken for each bit combination.

Table 6-1. FRZx Control Bits

FRZ1	FRZ0	Action
0	0	Ignore FREEZE
0	1	Reserved
1	0	Freeze on Boundary*
1	1	Reserved

*The boundary is defined as any bus cycle by the DMA module.

NOTE

The DMA module uses only one set of FRZx bits for both channels. A read or write to either MCR accesses the same FRZx control bits.

6- 24MC68340 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 MCR1, MCR2, FRZx Control Bits, Action

Models: MC68340

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

MCR1, MCR2

Table 6-1. FRZx Control Bits

FRZ1

FRZ0

Action

MC68340 specifications