80C52 Datasheet, PDF (19/23 Pages) Intel Corporation – CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

8XC52 54 58
PROGRAMMING THE EPROM
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_PP is held at logic high until just before ALE
PROG is to be pulsed The EA V_PP is raised to V_PP
ALE PROG is pulsed low and then EA V_PP is re-
turned to a high (also refer to timing diagrams)
DEFINITION OF TERMS
ADDRESS LINES P1 0 – P1 7 P2 0 – P2 5 respec-
tively for A0 – A13
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_PP
NOTES
 Exceeding the V_PP maximum for any amount of
time could damage the device permanently The
V_PP source must be well regulated and free of
glitches
Mode
Program Code Data
Verify Code Data
Program Encryption
Array Address 0– 3FH
Program Lock
Bits
Bit 1
Bit 2
Bit 3
Read Signature Byte
Table 4 EPROM Programming Modes
RST
H
PSEN
L
ALE
PROG
EA
V_PP
12 75V
P2 6
L
P2 7
H
H
L
H
H
L
L
H
L
12 75V L
H
H
L
H
L
H
L
H
L
12 75V H
H
12 75V H
H
12 75V H
L
H
H
L
L
P3 3
H
L
H
H
H
H
L
P3 6
H
H
L
H
L
H
L
P3 7
H
H
H
H
L
L
L
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