TSC87C52

13

MATRA MHS

Rev. C – 10 Sept 1997

Preliminary

Control

signals

Data In

ALE/PROG

A0–A12

Programming Cycle

1

2

3

5

4

10us

100us

D0–D7

EA/VPP

Data Out

Read/Verify Cycle

12.75V

5V

0V

Figure 9 Programming and verification signal’s waveform

Signature bytes

for EPROM verify but activate the control lines provided in Table 6 for Read Signature Bytes. Table 7 shows the

Table 7 Signature bytes content

Location

Contents

Comment

30h

58h

Customer selection byte: TEMIC

31h

58h

Family selection byte: C51

60h

ADh

TSC87C52

61h

XXh

Product revision number

EPROM Erasure (Windowed Packages Only)

Erasing the EPROM erases the code array and also the encryption array returning the parts to full functionality.

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

Erasure Characteristics

The recommended erasure procedure is exposure to ultraviolet light (at 2537 Å) to an integrated dose at least 15

about 25 mm, should be sufficient.

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

over the window.