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Intel Microcontroller manual BUS-HOLD Protocol, Ready Timing Diagram Demultiplexed Mode 80C196NU

Models: Microcontroller 80C196NU 8XC196NP

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8XC196NP, 80C196NU USER’S MANUAL

 

CLKOUT

TCHYX (max)

 

TCHYX (min)

 

TAVYV

 

READY

 

ALE

TLHLH + 2t

 

RD#

TRLRH + 2t

 

 

TRLDV + 2t

AD15:0

TAVDV + 2t

Data Valid

(read)

 

WR#

TWLWH + 2t

 

 

TQVWH + 2t

AD15:0

Data Valid

(write)

 

BHE#, INST

 

A19:16

 

CSx#

 

 

T0014-02

Figure 13-15. READY Timing Diagram — Demultiplexed Mode (80C196NU)

13.7 BUS-HOLD PROTOCOL

The 8XC196Nx supports a bus-hold protocol that allows external devices to gain control of the address/data bus. The protocol uses three signals, all of which are port 2 special functions: HOLD#/P2.5 (bus-hold request), HLDA#/P2.6 (bus-hold acknowledge), and BREQ#/P2.3 (bus request). When an external device wants to use the 8XC196Nx bus, it asserts the HOLD# signal. HOLD# is sampled while CLKOUT is low. The 8XC196Nx responds by releasing the bus and asserting HLDA#. During this hold time, the address/data bus floats, and signals CSx#, ALE, RD#, WR#/WRL#, BHE#/WRH#, and INST are weakly held in their inactive states. Figure 13-16 shows the timing for bus-hold protocol, and Table 13-12 on page 13-31 lists the timing pa- rameters and their definitions. Refer to the datasheet for timing parameter values.

13-30

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Intel Microcontroller, 8XC196NP manual BUS-HOLD Protocol, Ready Timing Diagram Demultiplexed Mode 80C196NU
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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.