87C524 데이터 시트보기 (PDF) - Philips Electronics

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87C524

80C51 8-bit microcontrollers 16K/32K, 512 OTP, I2C, watchdog timer

Philips Electronics 

Philips Semiconductors

80C51 8-bit microcontrollers

16K/32K, 512 OTP, I2C, watchdog timer

Product specification

87C524/87C528

EPROM CHARACTERISTICS FOR 87C524

The 87C524 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 87C524 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 87C524 manufactured by

Philips.

Table 6 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 14 and 15. Figure 16 shows the

circuit configuration for normal program memory verification.

Quick-Pulse Programming

The setup for microcontroller quick-pulse programming is shown in

Figure 14. Note that the 87C524 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, 2 and 3, as shown in Figure 14. 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 6 are held at the ‘Program

Code Data’ levels indicated in Table 6. The ALE/PROG is pulsed

low 25 times as shown in Figure 15.

To program the encryption table, repeat the 25 pulse programming

sequence for addresses 0 through 3FH, 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, 2 and 3 as shown

in Figure 16. The other pins are held at the ‘Verify Code Data’ levels

indicated in Table 6. 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.

Program Lock Bits

The 87C524 has 3 programmable lock bits that will provide different

levels of protection for the on-chip code and data (see Table 7).

Erasing the EPROM also erases the encryption array and the

program lock bits, returning the part to full functionality.

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) = 9DH indicates 87C524

Program/Verify Algorithms

Any algorithm in agreement with the conditions listed in Table 6, 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 12,000uW/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.

™Trademark phrase of Intel Corporation.

1999 Jul 23

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