14-5
PROGRAMMING AND VERIFYING NONVOLATILE MEMORY
Figure 14-1. Setup for Programming and Verifying Nonvolatile Memory
14.4 PROGRAMMING ALGORITHM
The procedure for programming the 87C251Sx is as follows:
1.
Set up the controller for operation in the appropriate mode according to Table 14-1.
2.
Input the 16-bit address on ports 1 and 3.
3.
Input the data byte on port 2.
4.
Raise the voltage on the V
PP
pin from 5 V to 12.75 V.
5.
Pulse the PROG# pin 5 times for the on-chip code memory and the configuration bytes,
and 25 times for the encryption array and the lock bits.
6.
Reduce the voltage on the V
PP
pin to 5 V.
7.
If the procedure is program/immediate-verify, go to section 14.5, “Verify Algorithm,” and
perform steps 1 through 4 to verify the currently addressed byte. Make sure the voltage on
the EA#/V
PP
pin has been lowered to 5 V before performing the verifying procedure.
8.
Repeat steps 1 through 7 until all memory locations are programmed.
P0
PSEN#
ALE/PROG#
EA#/V
pp
8XC251S
x
A4122-02
4 MHz
to
6 MHz
XTAL2
A0 - A7
A8 - A15
P3
P1
Data
(8 Bits)
V
SS
V
CC
V
CC
XTAL1
Programming
Signals
Address
(16 Bits)
Program/Verify Mode
(8 Bits)
P2
RST
Содержание 8XC251SA
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Страница 3: ...May 1996 8XC251SA 8XC251SB 8XC251SP 8XC251SQ Embedded Microcontroller User s Manual...
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Страница 19: ...1 Guide to This Manual...
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Страница 31: ...2 Architectural Overview...
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Страница 41: ...3 Address Spaces...
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Страница 63: ...4 Device Configuration...
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Страница 81: ...5 Programming...
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Страница 103: ...6 Interrupt System...
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Страница 121: ...7 Input Output Ports...
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Страница 133: ...8 Timer Counters and Watchdog Timer...
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Страница 153: ...9 Programmable Counter Array...
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Страница 171: ...10 Serial I O Port...
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Страница 187: ...11 Minimum Hardware Setup...
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Страница 197: ...12 Special Operating Modes...
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Страница 207: ...13 External Memory Interface...
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Страница 239: ...14 Programming and Verifying Nonvolatile Memory...
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Страница 251: ...A Instruction Set Reference...
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Страница 391: ...B Signal Descriptions...
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Страница 401: ...C Registers...
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Страница 437: ...Glossary...
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Страница 447: ...Index...
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