AT87251G2D-3CSUM【PDF 35/77 页】IC 8051 MCU 32K OTP 24MHZ 40DIP

收藏本站

您好，
买卖IC网欢迎您。
请登录
免费注册

买卖IC网

Sheet目录3833

31页 32页 33页 34页 [35页]36页 37页 38页 39页

AT/TSC8x251G2D

4135F–8051–11/06

Programming and Verifying Non-volatile Memory

Internal Features

The internal non-volatile memory of the TSC80251G2D derivatives contains five differ-

ent areas:

Code Memory

Configuration Bytes

Lock Bits

Encryption Array

Signature Bytes

EPROM/OTPROM Devices

All the internal non-volatile memory but the Signature Bytes of the TSC87251G2D prod-

ucts is made of EPROM cells. The Signature Bytes of the TSC87251G2D products are

made of Mask ROM.

The TSC87251G2D products are programmed and verified in the same manner as

Atmel’s TSC87251G1A, using a SINGLE-PULSE algorithm, which programs at

VPP = 12.75V using only one 100μs pulse per byte. This results in a programming time

of less than 10 seconds for the 32 kilobytes on-chip code memory.

The EPROM of the TSC87251G2D products in Window package is erasable by Ultra-

Violet radiation(1) (UV). UV erasure set all the EPROM memory cells to one and allows

reprogramming. The quartz window must be covered with an opaque label(2) when the

device is in operation. This is not so much to protect the EPROM array from inadvertent

erasure, as to protect the RAM and other on-chip logic. Allowing light to impinge on the

silicon die during device operation may cause a logical malfunction.

The TSC87251G2D products in plastic packages are One Time Programmable (OTP).

An EPROM cell cannot be reset by UV once programmed to zero.

Notes: 1. The recommended erasure procedure is exposure to ultra-violet light (at 2537 ) to

an integrated dose of at least 20 W-sec/cm2. Exposing the EPROM to an ultra-violet

lamp of 12000 μW/cm2 rating for 30 minutes should be sufficient.

2. Erasure of the EPROM begins to occur when the chip is exposed to light wavelength

shorter than 4000 . Since sunlight and fluorescent light have wavelength in this

range, exposure to these light sources over an extended time (1 week in sunlight or 3

years in room-level fluorescent lighting) could cause inadvertent erasure.

Mask ROM Devices

All the internal non-volatile memory of TSC83251G2D products is made of Mask ROM

cells. They can only be verified by the user, using the same algorithm as the

EPROM/OTPROM devices.

ROMless Devices

The TSC80251G2D products do not include on-chip Configuration Bytes, Code Memory

and Encryption Array. They only include Signature Bytes made of Mask ROM cells

which can be read using the same algorithm as the EPROM/OTPROM devices.

Security Features

In some microcontroller applications, it is desirable that the user’s program code be

secured from unauthorized access. The TSC83251G2D and TSC87251G2D offer two

kinds of protection for program code stored in the on-chip array:

Program code in the on-chip Code Memory is encrypted when read out for

verification if the Encryption Array isprogrammed.

A three-level lock bit system restricts external access to the on-chip code memory.

发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

*型号	*数量	厂商	批号	封装

添加更多采购

采购需求

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

我的联系方式