PULSE-WIDTH MODULATOR

Table 9-2. PWM Control and Status Registers

Mnemonic

Address

Description

 

 

 

CON_REG0

1FB6H

PWM Control Register

 

 

This register controls the clock prescaler.

 

 

Bit 0 (CLK0) controls the output period of the PWM

 

 

channels by enabling or disabling the divide-by-two clock

 

 

prescaler (8XC196NP only).

 

 

Bits 0 and 1 (CLK0, CLK1) control the output period of the

 

 

PWM channels by enabling or disabling the divide-by-two

 

 

or divide-by-four clock prescaler (80C196NU only).

 

 

 

PWM0_CONTROL

1FB0H

PWM Duty Cycle

PWM1_CONTROL

1FB2H

This register controls the PWM duty cycle. A zero loaded

PWM2_CONTROL

1FB4H

into this register causes the PWM to output a low continu-

 

 

 

 

ously (0% duty cycle). An FFH in this register causes the

 

 

PWM to have its maximum duty cycle (99.6% duty cycle).

 

 

 

P4_DIR

1FDBH

Port 4 Direction

 

 

The P4_DIR register determines the I/O mode for each

 

 

port 4 pin. The register settings for an open-drain output or

 

 

a high-impedance input are identical. An open-drain

 

 

output configuration requires an external pull-up. A high-

 

 

impedance input configuration requires that the corre-

 

 

sponding bit in P4_REG be set. This port has a higher

 

 

drive capability than the other ports in order to support

 

 

PWM high-drive output requirements.

 

 

 

P4_MODE

1FD9H

Port 4 Mode

 

 

Each bit in this register determines whether the corre-

 

 

sponding pin functions as a standard I/O port pin or is

 

 

used for a special-function signal.

 

 

 

P4_PIN

1FDFH

Port 4 Pin State

 

 

P4_PIN contains the current state of each port pin,

 

 

regardless of the pin mode setting.

 

 

 

P4_REG

1FDDH

Port 4 Output Data

 

 

P4_REG contains data to be driven out by the respective

 

 

pins. When a port pin is configured as an input, the corre-

 

 

sponding bit in P4_REG must be set.

 

 

 

9.3PWM OPERATION

For the 8XC196NP, CON_REG0.0 (CLK0) controls the PWM output frequency by enabling or disabling the divide-by-two clock prescaler. Enabling the prescaler causes the 8-bit counter to in- crement once every two state times; disabling it causes the counter to increment once every state time.

9-3

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Intel Microcontroller, 80C196NU, 8XC196NP manual PWM Operation, PWM Control and Status Registers

Microcontroller, 80C196NU, 8XC196NP specifications

The Intel 8XC196NP and 80C196NU microcontrollers are part of Intel's renowned 16-bit microcontroller series that gained popularity in the 1980s and 1990s for embedded systems applications. Designed for a variety of applications, these microcontrollers are characterized by their robust performance, versatility, and industry-standard architecture.

The 8XC196NP features an enhanced instruction set with over 100 instructions, allowing for efficient code execution. It operates at clock speeds up to 16 MHz, which contributes to improved performance in time-sensitive applications. The microcontroller is equipped with a 16-bit data bus, enabling more efficient data handling compared to its 8-bit predecessors, thus accommodating complex algorithms and large data sets.

In terms of memory architecture, the 8XC196NP supports an addressable memory space of up to 64 KB of program memory and 64 KB of data memory. This configuration provides sufficient space for large applications while ensuring fast data access. The microcontroller includes integrated features such as timers, serial I/O capabilities, and interrupt processing, which enhance its functionality for real-time applications and control mechanisms.

The 80C196NU, on the other hand, is designed for lower power operation, making it suitable for battery-powered devices. This microcontroller maintains similar features to the 8XC196NP while offering advancements that support low-power consumption. The 80C196NU can also function in a range of temperature environments, making it adaptable for industrial applications.

Both the 8XC196NP and 80C196NU support external memory interfacing, allowing designers to expand the system's capability by connecting additional ROM and RAM. This flexibility makes them appealing for developing complex systems, such as motor controls, industrial automation, and consumer electronics.

Another standout feature of these microcontrollers is their built-in debugging capabilities. Intel provided hardware and software tools that enabled developers to test and troubleshoot their applications effectively, reducing the development time and increasing reliability.

Overall, the Intel 8XC196NP and 80C196NU microcontrollers stand out for their dependability, versatility, and performance, contributing significantly to the evolution of embedded system design. Their legacy continues to influence modern microcontroller technology, ensuring their relevance in a wide array of applications today.