Tba, Tbb, Ipcr | Motorola MC68340 instruction

Freescale Semiconductor, Inc.

characters until the shift register is ready to accept more data. When the shift register is empty, it checks to see if the holding register has a valid character to be sent (TxRDY bit cleared). If there is a valid character, the shift register loads the character and reasserts the TxRDY bit in the channel's SR. Writes to the transmitter buffer when the channel's SR TxRDY bit is clear and when the transmitter is disabled have no effect on the transmitter buffer. This register can only be written when the serial module is enabled (i.e., the STP bit in the MCR is cleared).

TBA, TBB						$713, $71B
7	6	5	4	3	2	1	0
TB7	TB6	TB5	TB4	TB3	TB2	TB1	TB0
RESET:
0	0	0	0	0	0	0	0
Write Only					Supervisor/User

TB7–TB0—These bits contain the character in the transmitter buffer.

7.4.1.10INPUT PORT CHANGE REGISTER (IPCR). The IPCR shows the current state and the change-of-state for the CTSA and CTSB pins. This register can only be read when the serial module is enabled (i.e., the STP bit in the MCR is cleared).

IPCR							$714
7	6	5	4	3	2	1	0
0	0	COSB	COSA	0	0	CTSB	CTSA
RESET:
0	0	0	0	0	0	U	U
Read Only					Supervisor/User

Bits 7, 6, 3, 2—Reserved

COSB, COSA—Change-of-State

1 = A change-of-state (high-to-low or low-to-high transition), lasting longer than 25–

50 ∝s when using a crystal as the sampling clock or longer than one or two periods when using SCLK, has occurred at the corresponding CTS≈ input (MCR ICCS bit controls selection of the sampling clock for clear-to-send operation). When these bits are set, the ACR can be programmed to generate an interrupt to the CPU32.

0 = The CPU32 has read the IPCR. No change-of-state has occurred. A read of the IPCR also clears the ISR COS bit.

CTSB, CTSA—Current State

Starting two serial clock periods after reset, the CTS≈ bits reflect the state of the CTS≈ pins. If a CTS≈ pin is detected as asserted at that time, the associated COSx bit will be set, which will initiate an interrupt if the corresponding IECx bit of the ACR register is enabled.

1 = The current state of the respective CTS≈ input is negated.

0 = The current state of the respective CTS≈ input is asserted.

MOTOROLAMC68340 USER’S MANUAL7- 31

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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 Tba, Tbb, Ipcr

Models: MC68340

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

TBA, TBB

IPCR

MOTOROLAMC68340 USER’S MANUAL7- 31

MC68340 specifications