80C31BH Datasheet, PDF (13/16 Pages) Intel Corporation – CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

AUTOMOTIVE 80C31BH 80C51BH 87C51
EPROM CHARACTERISTICS
(EPROM Only)
The 87C51 is programmed by 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 87C51 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 87C51 manufactured by Intel
Table 3 shows the logic levels for reading the signa-
ture byte and for programming the Program Memo-
ry the Encryption Table and the Lock Bits The cir-
cuit configuration and waveforms for Quick-Pulse
Programming are shown in Figures 11 and 12 Fig-
ure 13 shows the circuit configuration for normal
Program Memory verification
MODE
Read Signature
Program Code Data
Verify Code Data
Pgm Encryption Table
Pgm Lock Bit 1
Pgm Lock Bit 2
Table 3 EPROM Programming Modes
RST
PSEN
ALE
PROG
EA
V_PP
P2 7
1
0
1
1
0
1
0
0
V_PP
1
1
0
1
1
0
1
0
0
V_PP
1
1
0
0
V_PP
1
1
0
0
V_PP
1
P2 6
0
0
0
0
1
1
P3 7
0
1
1
1
1
0
P3 6
0
1
1
0
1
0
NOTES
‘‘1’’ e Valid high for that pin
‘‘0’’ e Valid low for that pin
V_PP e 12 75V g 0 25V
V_CC e 5V g20% during programming and verification
ALE PROG receives 25 programming pulses while V_PP is held at 12 75V Each programming pulse is low for 100 ms
(g10 ms) and high for a minimum of 10 ms
Figure 11 Programming Configuration
270419 – 19
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