8XC196NP, 80C196NU USER’S MANUAL

P2.7/CLKOUT

Following reset, P2.7 carries the strongly driven CLKOUT signal. It

 

is not held high. When P2.7 is configured as CLKOUT, it is always a

 

complementary output.

P2.7

A value written to P2_REG.7 is held in a buffer until P2_MODE.7 is

 

cleared, at which time the value is loaded into P2_REG.7. A value

 

read from P2_REG.7 is the value currently in the register, not the

 

value in the buffer. Therefore, any change to P2_REG.7 can be read

 

only after P2_MODE.7 is cleared.

Port 3

After reset, your software must configure the device to match the

 

external system. This is accomplished by writing appropriate config-

 

uration data into P3_MODE. Writing to P3_MODE not only

 

configures the pins but also turns off the transistor that weakly holds

 

the pins high (Q4 in Figure 7-1 on page 7-5). For this reason, even if

 

port 3 is to be used as it is configured at reset, you should still write

 

data into P3_MODE.

P3.0/CS0#

P3.0/CS0# is weakly pulled high during reset. After reset, it defaults

 

to the CS0# function. This chip-select signal detects address ranges

 

that contain the CCBs and FF2080H (program start-up address). See

 

Chapter 13, “Interfacing with External Memory,” for a detailed

 

description of chip-select signal functions after reset.

P3.6/EXTINT2

Writing to P3_MODE.6 sets the EXTINT2 interrupt pending bit

 

(INT_PEND1.5). After configuring the port pins, clear the interrupt

 

pending registers before globally enabling interrupts. See “Design

 

Considerations for External Interrupt Inputs” on page 7-11.

P3.7/EXTINT3

Writing to P3_MODE.7 sets the EXTINT3 interrupt pending bit

 

(INT_PEND1.6). After configuring the port pins, clear the interrupt

 

pending registers before globally enabling interrupts. See “Design

 

Considerations for External Interrupt Inputs” on page 7-11.

Port 4

After reset, your software must configure the device to match the

 

external system. This is accomplished by writing appropriate config-

 

uration data into P4_MODE. Writing to P4_MODE not only

 

configures the pins but also turns off the transistor that weakly holds

 

the pins high (Q4 in Figure 7-1 on page 7-5). For this reason, even if

 

port 4 is to be used as it is configured at reset, you should still write

 

data into P4_MODE.

7-10

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Intel Microcontroller, 80C196NU, 8XC196NP manual P2.7/CLKOUT
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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.
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