87C652 datasheet(17/24 Pages) PHILIPS

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Philips Semiconductors

Product specification

87C652/87C654

80C51 8-bit microcontroller

8K/16K, 256 OTP, I2C

1999 Jul 23

EPROM CHARACTERISTICS

The 87C652/87C654 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 87C652/87C654 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 87C652/87C654 manufactured by

Philips Components.

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 12 and 13. Figure 14 shows

the circuit configuration for normal program

memory verification.

Quick-Pulse Programming

The setup for microcontroller quick-pulse

programming is shown in Figure 12. Note

that the 87C652/87C654 is running with a

4 to 6 MHz 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 12. 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 25 times as shown

in Figure 13.

To program the encryption table, repeat the 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 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 14. 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) = 99H

Program/Verify Algorithms

Any algorithm in agreement with the

conditions listed in Table 4, and which

satisfies the timing specifications, is suitable.

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 = 12.75 V ±0.25 V.

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

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

minimum of 10

µs.

™Trademark phrase of Intel Corporation.

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