80C453 Datasheet, PDF (21/23 Pages) NXP Semiconductors – CMOS single-chip 8-bit microcontrollers

Philips Semiconductors
CMOS single-chip 8-bit microcontrollers
Preliminary specification
80C453/83C453/87C453
EPROM CHARACTERISTICS
The 87C453 is programmed by using a modified Quick-Pulse
Programming™ algorithm. It differs from older methods in the value
used for V_PP (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/V_PP pin must not be allowed to go above the
maximum specified V_PP level for any amount of time. Even a narrow
glitch above that voltage can cause permanent damage to the
device. The V_PP 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 12,000µW/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
Read signature
RST
1
PSEN
0
ALE/PROG
1
EA/V_PP
1
P2.7
0
P2.6
0
P3.7
0
P3.6
0
Program code data
Verify code data
1
0
0*
V_PP
1
0
1
1
1
0
1
1
0
0
1
1
Pgm encryption table
1
0
0*
V_PP
1
0
1
0
Pgm lock bit 1
1
0
0*
V_PP
1
1
1
1
Pgm lock bit 2
1
0
0*
V_PP
1
1
0
0
NOTES:
1. ‘0’ = Valid low for that pin, ‘1’ = valid high for that pin.
2. V_PP = 12.75V ±0.25V.
3. V_CC = 5V ±10% during programming and verification.
* ALE/PROG receives 15 to 25 programming pulses while V_PP is held at 12.75V. Each programming pulse is low for 100µs (±10µs) and high
for a minimum of 10µs.
™Trademark phrase of Intel Corporation.
1996 Aug 15
3-331