Bdm, Size Field Encoding, Encoding Operand Size

Freescale Semiconductor, Inc.

DSCLK, the gated serial clock, is normally high, but it pulses low for each bit to be transferred. At the end of the seventeenth clock period, it remains high until the start of the next transmission. Clock frequency is implementation dependent and may range from DC to the maximum specified frequency. Although performance considerations might dictate a hardware implementation, software solutions can be used provided serial bus timing is maintained.

5.6.2.8COMMAND SET. The following paragraphs describe the command set available in

BDM.

5.6.2.8.1Command Format. The following standard bit format is utilized by all BDM commands.

15	10	9	8	7	6	5	4	3	2	0
OPERATION		0	R/W	OP SIZE		0	0	A/D		REGISTER
			EXTENSION WORD(S)

Bits 15–0—Operation Field

The operation field specifies the commands. This 6-bit field provides for a maximum of 64 unique commands.

R/W Field

The R/W field specifies the direction of operand transfer. When the bit is set, the transfer is from CPU to development system. When the bit is cleared, data is written to the CPU or to memory from the development system.

Operand Size

For sized operations, this field specifies the operand data size. All addresses are expressed as 32-bit absolute values. The size field is encoded as listed in Table 5-22.

Table 5-22. Size Field Encoding

Encoding	Operand Size
00	Byte
01	Word
10	Long
11	Reserved

Address/Data (A/D) Field

The A/D field is used by commands that operate on address and data registers. It determines whether the register field specifies a data or address register. One indicates an address register; zero indicates a data register. For other commands, this field may be interpreted differently.

MOTOROLAMC68340 USER’S MANUAL5- 73

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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 Bdm, Size Field Encoding, Encoding Operand Size

Models: MC68340

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

BDM.

Table 5-22. Size Field Encoding

Encoding

Operand Size

MC68340 specifications