CPU Special-function Registers SFRs, CPU SFRs

8XC196NP, 80C196NU USER’S MANUAL

Subroutines may be nested. That is, each subroutine may call other subroutines. The CPU PUSH- es the contents of the program counter onto the stack each time it executes a subroutine call. The stack grows downward as entries are added. The only limit to the nesting depth is the amount of available memory. As the CPU returns from each nested subroutine, it POPs the address off the top of the stack, and the next return address moves to the top of the stack.

Your program must load a word-aligned (even) address into the stack pointer. Select an address that is two bytes (for 64-Kbyte mode) or four bytes (for 1-Mbyte mode) greater than the desired starting address because the CPU automatically decrements the stack pointer before it pushes the first byte of the return address onto the stack. Remember that the stack grows downward, so allow sufficient room for the maximum number of stack entries. The stack must be located in page 00H, in either the internal register file or external RAM. The stack can be used most efficiently when it is located in the upper register file.

The following example initializes the top of the upper register file as the stack.

SP, #400H

;Load stack pointer

5.2.4.3CPU Special-function Registers (SFRs)

Locations 0000–0017H in the lower register file are the CPU SFRs. Table 5-7 lists the CPU SFRs for the 8XC196NP and the 80C196NU and highlights those that are unique to the 80C196NU. Appendix C describes the CPU SFRs.

Table 5-7. CPU SFRs

8XC196NP CPU SFRs

Address	High (Odd) Byte	Low (Even) Byte

0016H	Reserved	Reserved
0014H	Reserved	WSR
0012H	INT_MASK1	INT_PEND1
0010H	Reserved	Reserved
000EH	Reserved	Reserved
000CH	Reserved	Reserved
000AH	Reserved	Reserved
0008H	INT_PEND	INT_MASK
0006H	PTSSRV (H)	PTSSRV (L)
0004H	PTSSEL (H)	PTSSEL (L)
0002H	ONES_REG (H)	ONES_REG (L)
0000H	ZERO_REG (H)	ZERO_REG (L)

†These SFRs are unique to the 80C196NU.

††Must be addressed as a word.

80C196NU CPU SFRs

Address	High (Odd) Byte	Low (Even) Byte

0016H	Reserved	Reserved
0014H	WSR1†	WSR
0012H	INT_MASK1	INT_PEND1
0010H	Reserved	Reserved
000EH††	ACC_03†	ACC_02†
000CH††	ACC_01†	ACC_00†
000AH	ACC_STAT†	Reserved
0008H	INT_PEND	INT_MASK
0006H	PTSSRV (H)	PTSSRV (L)
0004H	PTSSEL (H)	PTSSEL (L)
0002H	ONES_REG (H)	ONES_REG (L)
0000H	ZERO_REG (H)	ZERO_REG (L)

5-12

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 8XC196NP, 80C196NU, Microcontroller manual CPU Special-function Registers SFRs, CPU SFRs

Models: Microcontroller 80C196NU 8XC196NP