87C51 Intel Corporation, 87C51 Datasheet - Page 17

• Manufacturer Part Number: 87C51
• Description: CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLER
• Manufacturer: Intel Corporation

PROGRAMMING THE 87C51
The part must be running with a 4 MHz to 6 MHz
oscillator The address of an EPROM location to be
programmed is applied to address lines while the
code byte to be programmed in that location is ap-
plied to data lines Control and program signals must
be held at the levels indicated in Table 4 Normally
EA V
ALE PROG is to be pulsed The EA V
V
returned to a high (also refer to timing diagrams)
PP
Program Code Data
Verify Code Data
Program Encryption
Array Address 0– 3F
Program Lock Bits
Read Signature Byte
See Table 4 for proper input on these pins
Exceeding the V
time could damage the device permanently The
V
glitches
PP
ALE PROG is pulsed low and then EA V
PP
source must be well regulated and free of
is held at logic high until just before
Mode
PP
NOTE
maximum for any amount of
Bit 1
Bit 2
Bit 3
RST
H
H
H
H
H
H
H
Table 4 EPROM Programming Modes
Figure 10 Programming the EPROM
PP
PSEN
is raised to
L
L
L
L
L
L
L
PP
PROG
is
ALE
H
H
DEFINITION OF TERMS
ADDRESS LINES P1 0 – P1 7 P2 0 – P2 5 P3 4 re-
spectively for A0 – A14
DATA LINES P0 0 – P0 7 for D0 – D7
CONTROL SIGNALS RST PSEN P2 6 P2 7 P3 3
P3 6 P3 7
PROGRAM SIGNALS ALE PROG EA V
12 75V
12 75V
12 75V
12 75V
12 75V
EA
V
H
H
PP
P2 6
H
H
H
L
L
L
L
87C51 80C51BH 80C31BH
P2 7
H
H
H
H
L
L
L
P3 3
H
H
H
H
H
L
L
272335 –21
P3 6
H
H
H
H
L
L
L
PP
P3 7
H
H
H
H
L
L
L
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