Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

Each communication channel is completely independent. Data formats can be 5, 6, 7, or 8 bits with even, odd, or no parity and stop bits up to 2 in 1/16 increments. Four-byte receive buffers and two-byte transmit buffers minimize CPU service calls. A wide variety of error detection and maskable interrupt capability is provided on each channel. Full-duplex, autoecho loopback, local loopback, and remote loopback modes can be selected. Multidrop applications are supported.

A 3.6864-MHz crystal drives the baud rate generators. Each transmit and receive channel can be programmed for a different baud rate, or an external 1 ⋅ and 16⋅ clock input can be selected. Full modem support is provided with separate request-to-send (RTS) and clear- to-send (CTS) signals for each channel. One channel also provides service request signals. The two serial ports can sustain rates of 9.8 Mbps with a 25-MHz system clock in 1⋅ mode, 612 kbps in 16⋅ mode (6.5 Mbps and 410 kbps @ 16.78 MHz).

1.3.4 Timer Modules

Timers and counters are used in a system to monitor elapsed time, generate waveforms, measure signals, keep time-of-day clocks, initiate DRAM refresh cycles, count events, and provide “time slices” to ensure that no task dominates the activity of the processor. A counter that counts clock pulses makes a timer, which is most useful when it causes certain actions to occur in response to reaching desired counts.

The MC68340 has two, identical, versatile, on-chip counter/timers as well as a simple timer in the SIM40. These general-purpose counter/timers can be used for precisely timed events without the errors to which software-based counters and timers are susceptible— e.g., errors caused by dynamic memory refreshing, DMA cycle steals, and interrupt servicing. The programmable timer operating modes are input capture, output compare, square-wave generation, variable duty-cycle square-wave generation, variable-width single-shot pulse generation, event counting, period measurement, and pulse-width measurement.

Each timer consists of a 16-bit countdown counter with an 8-bit countdown prescaler for a composite 24-bit resolution. The two timers can be externally cascaded for a maximum count width of 48 bits. The counter/timer can be clocked by the internal system clock generated by the SIM40 (⎟2) or by an external clock input. Either the processor or external stimuli can trigger the starting and stopping of the counter. When a counter reaches a predetermined value, either an external output signal can be driven, or an interrupt can be made to the CPU32. The finest resolution of the timer is 80 ns with a 25-MHz system clock (125 ns @ 16.78 MHz).

1.4 POWER CONSUMPTION MANAGEMENT

The MC68340 is very power efficient due to its advanced 0.8-∝HCMOS process technology and its static logic design. The resulting power consumption is typically 900 mW in full operation @ 25 MHz (650 mW @ 16.78 MHz)—far less than the comparable discrete component implementation the MC68340 can replace. For applications employing reduced voltage operation, selection of the MC68340V, which

1- 8MC68340 USER’S MANUALMOTOROLA

For More Information On This Product,

Go to: www.freescale.com

Page 31 Page 33
Page 32
Image 32
Motorola MC68340 manual Timer Modules, Power Consumption Management
Page 31 Page 33

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.
Top Page Image Contents