Intel 80C196NU Configuring Eport Pins for Extended-address Functions, Epdir Epmode Epreg

Models: Microcontroller 80C196NU 8XC196NP

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I/O PORTS

7.3.2Configuring EPORT Pins

Each EPORT pin can be individually configured to operate either as an extended-address signal or as an I/O pin in one of these modes:

complementary output (output only)

high-impedance input or open-drain output (input, output, or bidirectional)

7.3.2.1Configuring EPORT Pins for Extended-address Functions

The EPORT pins default to their extended-address functions upon reset (see Table B-5 on page B-13). During program execution, the pins can be reconfigured at any time from address to I/O and back to address. However, this is not recommended unless you understand the implications of changing memory addressing “on the fly.” To change a pin from I/O to address, clear the EP_REG.x bit and set the EP_MODE.x bit. (Clearing EP_REG.x is required for compatibility with software development tools.)

7.3.2.2Configuring EPORT Pins for I/O

To configure a pin for I/O, write the appropriate values to the control registers, in this order:

1.EP_DIR

2.EP_MODE

3.EP_REG

Table 7-13 lists the register settings for the EPORT pins.

Table 7-13. Configuration Register Settings for EPORT Pins

Desired Pin Configuration

Configuration Register Settings

EP_PIN

 

 

 

EP_DIR

EP_MODE

EP_REG

Value

 

 

 

 

 

 

 

 

Address

X

1

0††

address

Complementary output

0

0

data value

data value

 

 

 

 

 

Open-drain output

1

0

data value

data value

 

 

 

 

 

Input

1

0

1

I/O pin value

 

 

 

 

 

X = Don’t care.

†† Must be zero for compatibility with software tools.

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Intel 80C196NU, 8XC196NP manual Configuring Eport Pins for Extended-address Functions, Configuring Eport Pins for I/O

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.