Code Fetches in the 1-Mbyte Mode | Intel Microcontroller, 80C196NU

MEMORY PARTITIONS

5.5.3Code Fetches in the 1-Mbyte Mode

CCR1.1 (the MODE64 bit) controls whether the device operates in 1-Mbyte or 64-Kbyte mode. CCR1 is loaded with the contents of CCB1 at reset. When MODE64 is clear, the device operates in 1-Mbyte mode. In this mode, code can execute from any page in the 1-Mbyte address space. An extended jump, branch, or call instruction across pages changes the EPC value to the destina- tion page. For example, assume that code is executing from page FFH. The following code seg- ment branches to an external memory location in page 00H and continues execution.


0FF2090H:	LD	TEMP,#12H	; code		executing	in page FFH
	ST	TEMP,PORT1	; code		executing	in page FFH
	EBR	003000H	;	jump	to location 3000H		in page 00H
003000H:	ADD	TEMP,#50H	;	code	executing in page		00H

Code fetches are from external memory or internal memory, depending on the device, the instruc- tion address, and the value of the EA# input.

80C196NU:

Code executes from any page in external memory.

80C196NP:

For devices without internal nonvolatile memory, EA# must be tied low, and code executes from any page in external memory.

83C196NP:

Code in all locations except FF2000–FF2FFFH executes from external memory.

Instruction fetches from FF2000–FF2FFFH are controlled by the EA# input:

•If EA# is low, code executes from external memory.

•If EA# is high, code executes from internal ROM.

Note that the EA# input functions only for the address range FF2000–FF2FFFH.

5.5.4Code Fetches in the 64-Kbyte Mode

CCR1.1 (the MODE64 bit) controls whether the device operates in 1-Mbyte or 64-Kbyte mode. CCR1 is loaded with the contents of CCB1 at reset. When MODE64 is set, the device operates in 64-Kbyte mode. In this mode, the EPC (Figure 5-7 on page 5-23) is fixed at FFH, which allows instructions to execute from page FFH only. Extended jump, branch, and call instructions do not function in the 64-Kbyte mode.

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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.

Intel Microcontroller manual Code Fetches in the 1-Mbyte Mode, Code Fetches in the 64-Kbyte Mode

Models: Microcontroller 80C196NU 8XC196NP