AT80C51RA2-RLSIV datasheet(56/86 Pages) ATMEL

56 / 86 page

4188F–8051–01/08

AT/TS8xC51Rx2

The encryption array cannot be directly verified. Verification of the encryption array is done by

observing that the code array is well encrypted.

Figure 9-2.

Programming and Verification Signal’s Waveform

9.4

EPROM Erasure (Windowed Packages Only)

Erasing the EPROM erases the code array, the encryption array and the lock bits returning the

parts to full functionality.

Erasure leaves all the EPROM cells in a 1’s state (FF).

9.4.1

Erasure Characteristics

The recommended erasure procedure is exposure to ultraviolet light (at 2537 Å) to an integrated

dose at least 15 W-sec/cm2. Exposing the EPROM to an ultraviolet lamp of 12,000 µW/cm2 rat-

ing for 30 minutes, at a distance of about 25 mm, should be sufficient. An exposure of 1 hour is

recommended with most of standard erasers.

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

shorter than approximately 4,000 Å. Since sunlight and fluorescent lighting have wavelengths in

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

years in room-level fluorescent lighting) could cause inadvertent erasure. If an application sub-

jects the device to this type of exposure, it is suggested that an opaque label be placed over the

window.

10. Signature Bytes

The TS83/87C51RB2/RC2/RD2 has four signature bytes in location 30h, 31h, 60h and 61h. To

read these bytes follow the procedure for EPROM verify but activate the control lines provided in

Table 31. for Read Signature Bytes. Table 10-1. shows the content of the signature byte for the

TS87C51RB2/RC2/RD2.

Table 10-1.

Signature Bytes Content

Control signals

Data In

ALE/PROG

A0-A12

Programming Cycle

100µs

D0-D7

EA/VPP

Data Out

Read/Verify Cycle

12.75V

Location

Contents

Comment

30h

58h

Manufacturer Code: Atmel

31h

57h

Family Code: C51 X2

60h

7Ch

Product name: TS83C51RD2

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