PROGRAMMING AND VERIFYING NONVOLATILE MEMORY

VCC

 

 

8XC251Sx

VCC

 

A0 - A7

P3

 

RST

 

Address

 

 

 

 

(16 Bits)

 

 

P2

Data

A8 - A15

P1

 

(8 Bits)

 

 

 

 

EA#/Vpp

Programming

 

XTAL1

ALE/PROG#

Signals

 

 

4 MHz

 

 

PSEN#

 

to

 

 

 

 

 

 

 

6 MHz

 

 

 

 

 

XTAL2

 

 

Program/Verify Mode

 

 

 

P0

 

VSS

 

(8 Bits)

 

 

 

 

 

 

 

A4122-02

Figure 14-1. Setup for Programming and Verifying Nonvolatile Memory

14.4 PROGRAMMING ALGORITHM

The procedure for programming the 87C251Sx is as follows:

1.Set up the controller for operation in the appropriate mode according to Table 14-1.

2.Input the 16-bit address on ports 1 and 3.

3.Input the data byte on port 2.

4.Raise the voltage on the VPP pin from 5 V to 12.75 V.

5.Pulse the PROG# pin 5 times for the on-chip code memory and the configuration bytes, and 25 times for the encryption array and the lock bits.

6.Reduce the voltage on the VPP pin to 5 V.

7.If the procedure is program/immediate-verify, go to section 14.5, “Verify Algorithm,” and perform steps 1 through 4 to verify the currently addressed byte. Make sure the voltage on the EA#/VPP pin has been lowered to 5 V before performing the verifying procedure.

8.Repeat steps 1 through 7 until all memory locations are programmed.

14-5

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Intel 8XC251SA, 8XC251SP, 8XC251SQ, 8XC251SB, Embedded Microcontroller manual Programming Algorithm
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Embedded Microcontroller, 8XC251SP, 8XC251SA, 8XC251SQ, 8XC251SB specifications

The Intel 8XC251 series of embedded microcontrollers is a family of versatile and powerful devices, designed to meet the demands of a wide range of applications. With models such as the 8XC251SB, 8XC251SQ, 8XC251SA, and 8XC251SP, this series offers unique features while maintaining a high level of performance and reliability.

At the heart of the 8XC251 microcontrollers is the 8051 architecture, which provides a 16-bit processor capable of executing complex instructions efficiently. This architecture not only allows for a rich instruction set but also facilitates programming in assembly language and higher-level languages like C, which are essential for developing sophisticated embedded systems.

One of the significant features of the 8XC251 family is its integrated peripherals, including timer/counters, serial communication interfaces, and interrupt systems. These peripherals enable developers to implement timing functions, data communication, and real-time processing, all of which are crucial in modern embedded applications. The 8XC251SB and 8XC251SQ models, for instance, come equipped with multiple I/O ports that allow for interfacing with other devices and systems, enhancing their functionality in various environments.

The memory architecture of the 8XC251 devices is noteworthy, featuring on-chip ROM, RAM, and EEPROM. The on-chip memory allows for fast access times, which is essential for executing programs efficiently. Moreover, the EEPROM serves as non-volatile memory, enabling the storage of configuration settings and important data that must be retained even when power is lost.

In terms of operating voltage, the 8XC251 devices are designed to operate in a wide range, typically between 4.0V and 6.0V. This flexibility makes them suitable for battery-powered applications, where energy efficiency is critical. The power management features, including reduced power modes, further enhance their suitability for portable devices.

Lastly, the 8XC251 series is supported by a wide range of development tools and resources, allowing engineers and developers to streamline the development process. This support, combined with the microcontrollers' robust features, makes the Intel 8XC251 family a reliable choice for various embedded applications, such as industrial automation, automotive systems, and consumer electronics.

Overall, the Intel 8XC251SB, 8XC251SQ, 8XC251SA, and 8XC251SP deliver high performance, versatility, and ease of use, making them a preferred choice for embedded system designers looking to develop efficient and effective solutions.
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