P83C453EBAA datasheet(21/23 Pages) PHILIPS

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Philips Semiconductors

Preliminary specification

80C453/83C453/87C453

CMOS single-chip 8-bit microcontrollers

1996 Aug 15

3-331

EPROM CHARACTERISTICS

The 87C453 is programmed by using a modified Quick-Pulse

Programming

™ algorithm. It differs from older methods in the value

used for VPP (programming supply voltage) and in the width and

number of the ALE/PROG pulses.

The 87C453 contains two signature bytes that can be read and used

by an EPROM programming system to identify the device. The

signature bytes identify the device as an 87C453 manufactured by

Philips Semiconductors.

Table 4 shows the logic levels for reading the signature byte, and for

programming the program memory, the encryption table, and the

lock bits. The circuit configuration and waveforms for quick-pulse

programming are shown in Figures 25 and 26. Figure 27 shows the

circuit configuration for normal program memory verification.

Quick-Pulse Programming

The setup for microcontroller quick-pulse programming is shown in

Figure 26. Note that the 87C453 is running with a 4 to 6MHz

oscillator. The reason the oscillator needs to be running is that the

device is executing internal address and program data transfers.

The address of the EPROM location to be programmed is applied to

ports 1 and 2, as shown in Figure 25. The code byte to be

programmed into that location is applied to port 0. RST, PSEN and

pins of ports 2 and 3 specified in Table 4 are held at the ‘Program

Code Data’ levels indicated in Table 4. The ALE/PROG is pulsed

low 15 to 25 times, as shown in Figure 26.

To program the encryption table, repeat the 15 to 25 pulse

programming sequence for addresses 0 through 1FH, using the

‘Pgm Encryption Table’ levels. Do not forget that after the encryption

table is programmed, verification cycles will produce only encrypted

data.

To program the lock bits, repeat the 15 to 25 pulse programming

sequence using the ‘Pgm Lock Bit’ levels. After one lock bit is

programmed, further programming of the code memory and

encryption table is disabled. However, the other lock bit can still be

programmed.

Note that the EA/VPP pin must not be allowed to go above the

maximum specified VPP level for any amount of time. Even a narrow

glitch above that voltage can cause permanent damage to the

device. The VPP source should be well regulated and free of glitches

and overshoot.

Program Verification

If lock bit 2 has not been programmed, the on-chip program memory

can be read out for program verification. The address of the program

memory locations to be read is applied to ports 1 and 2 as shown in

Figure 27. The other pins are held at the ‘Verify Code Data’ levels

indicated in Table 4. The contents of the address location will be

emitted on port 0. External pull-ups are required on port 0 for this

operation.

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 cannot be read out.

Reading the Signature Bytes

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 are:

(030H) = 15H indicates manufactured by Philips

(031H) = B9H indicates 87C453

Program/Verify Algorithms

Any algorithm in agreement with the conditions listed in Table 4, and

which satisfies the timing specifications, is suitable.

Erasure Characteristics

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 extended time (about

1 week in sunlight, or 3 years in room level fluorescent lighting)

could cause inadvertent erasure. For this and secondary effects,

it is recommended that an opaque label be placed over the

window. For elevated temperature or environments where solvents

are being used, apply Kapton tape Fluorglas part number 2345–5, or

equivalent.

The recommended erasure procedure is exposure to ultraviolet light

(at 2537 angstroms) to an integrated dose of at least 15W-sec/cm2.

Exposing the EPROM to an ultraviolet lamp of 12,000

µW/cm2 rating

for 20 to 39 minutes, at a distance of about 1 inch, should be

sufficient.

Erasure leaves the array in an all 1s state.

Table 4.

EPROM Programming Modes

MODE

RST

PSEN

ALE/PROG

EA/VPP

P2.7

P2.6

P3.7

P3.6

Read signature

Program code data

VPP

Verify code data

Pgm encryption table

VPP

Pgm lock bit 1

VPP

Pgm lock bit 2

VPP

NOTES:

1. ‘0’ = Valid low for that pin, ‘1’ = valid high for that pin.

2. VPP = 12.75V ±0.25V.

3. VCC = 5V ±10% during programming and verification.

ALE/PROG receives 15 to 25 programming pulses while VPP is held at 12.75V. Each programming pulse is low for 100µs (±10µs) and high

for a minimum of 10

µs.

™Trademark phrase of Intel Corporation.

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