Event Count, Period Measurement Mode | Motorola MC68340 specs

Freescale Semiconductor, Inc.

COUNTER

CLOCK

COUNTER 0	f	f	f	f	f	f	f	f
	f	f	f	f	f	f	f	f
	f	f	f	f	f	f	f	f
	f	e	d	c	b	a	9	9
TGATE
ENABLE
ENABLE			PERIOD MEASURED
			PERIOD MEASURED
START							STOP	NO EFFECT
COUNTING							COUNTING

MODEx Bits in Control Register = 101

TGE Bit of Control Register = 1

Figure 8-9. Period Measurement Mode

If the counter counts down to the value stored in the COM register, the COM and TC bits in the SR are set. If the counter counts down to $0000, a timeout is detected. This sets the SR TO bit, and clears the SR COM bit. At timeout, the next falling edge of the counter clock reloads the counter with $FFFF. TOUTx transitions at timeout or is disabled as programmed by the OCx bits of the CR, and the OUT bit in the SR reflects the level on TOUTx.

To determine the number of cycles counted, the value in the CNTR must be read, inverted, and incremented by 1 (the first count is $FFFF which, in effect, includes a count of zero). The counter counts in a true 216 fashion. For measuring pulses of even greater duration, the value in the POx bits in the SR are readable and can be thought of as an extension of the least significant bits in the CNTR.

NOTE

Once the timer has been enabled, do not clear the SR TG bit until the pulse has been measured and TGATE≈ has been negated.

8.3.7 Event Count

This mode is used to count events by interpreting the falling edges of the counter clock as events (see Figure 8-10). These events may be external or internal to the chip—for example, counting the number of system clock cycles required to execute a sequence of instructions. As another example, by connecting AS to TINx, the number of bus cycles to complete a sequence of instructions could be counted. This mode can be selected by programming the CR MODEx bits to 110.

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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 Event Count, Period Measurement Mode

Models: MC68340

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

Figure 8-9. Period Measurement Mode

8.3.7 Event Count

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MC68340 specifications