Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

PREL1

 

 

 

 

 

 

 

 

 

 

 

 

 

$60C, $64C

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

PR1-15 PR1-14 PR1-13 PR1-12 PR1-11 PR1-10

PR1-9

PR1-8

PR1-7

PR1-6

PR1-5

PR1-4

PR1-3

PR1-2

PR1-1

PR1-0

RESET:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Supervisor/User

For some modes of operation, this register is also used to reload the counter one falling clock edge after a timeout occurs. Refer to 8.3 Operating Modes for more information on the individual modes.

8.4.7 Preload 2 Register (PREL2)

PREL2 is used in addition to PREL1 in the variable duty-cycle square-wave generator and variable-width single-shot pulse generator modes. When in either of these modes, the value in PREL1 is loaded into the counter on the first falling edge of the counter clock after the counter is enabled. After timeout, the value in PREL2 is loaded into the counter. This register can be be read and written when the timer module is enabled (i.e., the STP bit in the MCR is cleared). However, a write to this register must be completed before timeout for the new value to be reliably loaded into the counter.

PREL2

 

 

 

 

 

 

 

 

 

 

 

 

 

$60E, $64E

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

PR2-15 PR2-14 PR2-13 PR2-12 PR2-11 PR2-10

PR2-9

PR2-8

PR2-7

PR2-6

PR2-5

PR2-4

PR2-3

PR2-2

PR2-1

PR2-0

RESET:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Supervisor/User

8.4.8 Compare Register (COM)

The COM can be used in any mode. When the 16-bit counter reaches the value in the COM, the TC and COM bits in the SR are set. In the input capture/output compare mode, a compare event can be programmed to set, clear, or toggle TOUTx. The register can be be read and written when the timer module is enabled (i.e., the STP bit in the MCR is cleared).

COM

 

 

 

 

 

 

 

 

 

 

 

 

 

$610, $650

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

COM15 COM14 COM13 COM12 COM11 COM10

COM9

COM8

COM7

COM6

COM5

COM4

COM3

COM2

COM1

COM0

RESET:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Supervisor/User

The COM can be used to produce an interrupt when the SR TC bit has been enabled to produce an interrupt and the counter counts down to a preselected value. The COM can also be used to indicate that the timer is approaching timeout.

8- 26MC68340 USER’S MANUALMOTOROLA

For More Information On This Product,

Go to: www.freescale.com

Page 369 Page 371
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Image 370
Motorola MC68340 manual Preload 2 Register PREL2, Compare Register COM, PREL1
Page 369 Page 371

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.
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