80C31BH Datasheet, PDF(15/16 Page) Intel Corporation – CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

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80C31BH Datasheet, PDF (15/16 Pages) Intel Corporation – CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

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AUTOMOTIVE 80C31BH 80C51BH 87C51

Program Verification

(EPROM Only)

If Lock Bit 2 has not been programmed the on-chip

Program Memory can be read out for program verifi-

cation The address of the Program Memory location

to be read is applied to Ports 1 and 2 as shown in

Figure 13 The other pins are held at the ââVerify

Code Dataââ levels indicated in Table 3 The con-

tents of the addressed location will be emitted on

Port 0 External pullups are required on Port 0 for

this operation Detailed timing specifications are

shown in later sections of this datasheet

If the Encryption Table has been programmed the

data presented at Port 0 will be the Exclusive NOR

of the program byte with one of the encryption bytes

The user will have to know the Encryption Table

contents in order to correctly decode the verification

data The Encryption Table itself can not be read

out

Reading the Signature Bytes

(EPROM Only)

The signature bytes are read by the same procedure

as a normal verification of locations 030H and 031H

except that P3 6 and P3 7 need to be pulled to a

logic low The values returned are

(030H) e 89H indicates manufactured by Intel

(031H) e 57H indicates 87C51

Program Verify Algorithms

(EPROM Only)

Any algorithm in agreement with the conditions list-

ed in Table 3 and which satisfies the timing specifi-

cations is suitable

Erasure Characteristics

(EPROM Only)

Erasure of the EPROM begins to occur when the

chip is exposed to light with wavelengths shorter

than approximately 4 000 Angstroms Since sunlight

and fluorescent lighting have wavelengths in this

range exposure to these light sources over an ex-

tended time (about 1 week in sunlight or 3 years in

room level fluorescent lighting) could cause inadver-

tent erasure If an application subjects the device to

this type of exposure it is suggested that an opaque

label be placed over the window

The recommended erasure procedure is exposure

to ultraviolet light (at 2537 Angstroms) to an integrat-

ed dose of at least 15 W-sec cm2 Exposing the

EPROM to an ultraviolet lamp of 12 000 mW cm2

rating for 30 minutes at a distance of about 1 inch

should be sufficient

Erasure leaves the array in an all 1s state

EPROM PROGRAMMING AND VERIFICATION CHARACTERISTICS

(TA e 21 C to 27 C VCC e 5V g20% VSS e 0V)

Symbol

Parameter

Min

Max

VPP

IPP

1 TCLCL

TAVGL

TGHAX

TDVGL

TGHDX

TEHSH

TSHGL

TGHSL

TGLGH

TAVQV

TELQV

TEHQZ

TGHGL

Programming Supply Voltage

Programming Supply Current

Oscillator Frequency

Address Setup to PROG Low

Address Hold After PROG

Data Setup to PROG Low

Data Hold After PROG

P2 7 (ENABLE) High to VPP

VPP Setup to PROG Low

VPP Hold After PROG

PROG Width

Address to Data Valid

ENABLE Low to Data Valid

Data Float After ENABLE

PROG High to PROG Low

12 5

48TCLCL

13 0

110

48TCLCL

Units

MHz

▷