8XC196NP, 80C196NU USER’S MANUAL

Table 8-2. Serial Port Control and Status Registers (Continued)

Mnemonic

Address

Description

 

 

 

SP_STATUS

1FB9H

Serial Port Status

 

 

This register contains the serial port status bits. It has status bits for

 

 

receive overrun errors (OE), transmit buffer empty (TXE), framing

 

 

errors (FE), transmit interrupt (TI), receive interrupt (RI), and

 

 

received parity error (RPE) or received bit 8 (RB8). Reading

 

 

SP_STATUS clears all bits except TXE; writing a byte to SBUF_TX

 

 

clears the TXE bit.

 

 

 

8.3SERIAL PORT MODES

The serial port has both synchronous and asynchronous operating modes for transmission and re- ception. This section describes the operation of each mode.

8.3.1Synchronous Mode (Mode 0)

The most common use of mode 0, the synchronous mode, is to expand the I/O capability of the device with shift registers (see Figure 8-2). In this mode, the TXD pin outputs a set of eight clock pulses, while the RXD pin either transmits or receives data. Data is transferred eight bits at a time with the least-significant bit first. Figure 8-3 shows a diagram of the relative timing of these sig- nals. Note that only mode 0 uses RXD as an open-drain output.

Clock Inhibit

 

 

Shift / LOAD#

 

 

 

Px.x

Serial In

 

 

VCC

 

 

 

74HC05

 

 

 

15KΩ

 

 

 

Data

 

Shift Register

Q#

RXD

 

 

 

 

Clock

 

74HC165

 

 

 

TXD

 

 

 

 

Inputs

 

8XC196

 

 

 

VCC

Outputs

 

Device

 

 

Serial

 

 

 

In B

 

 

Serial In A

 

Shift Register

 

Clock

Clear

74HC164

 

 

 

 

Enable#

 

 

 

Px.x

 

 

 

A0264-02

Figure 8-2. Typical Shift Register Circuit for Mode 0

8-4

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Intel 80C196NU, 8XC196NP, Microcontroller manual Serial Port Modes, Synchronous Mode Mode, Spstatus 1FB9H

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.