AT89S52-33AC ATMEL Corporation, AT89S52-33AC Datasheet - Page 21

• Manufacturer Part Number: AT89S52-33AC
• Description: 8-bit Microcontroller with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL Corporation

Table 9. Serial Programming Instruction Set
Notes:
After Reset signal is high, SCK should be low for at least 64
system clocks before it goes high to clock in the enable
data bytes. No pulsing of Reset signal is necessary. SCK
should be no faster than 1/16 of the system clock at
XTAL1.
Instruction
Programming Enable
Chip Erase
Read Program Memory
(Byte Mode)
Write Program Memory
(Byte Mode)
Write Lock Bits
Read Lock Bits
Read Signature Bytes
Read Program Memory
(Page Mode)
Write Program Memory
(Page Mode)
1. The signature bytes are not readable in Lock Bit Modes 3 and 4.
2. B1 = 0, B2 = 0 ---> Mode 1, no lock protection
B1 = 0, B2 = 1 ---> Mode 2, lock bit 1 activated
B1 = 1, B2 = 0 ---> Mode 3, lock bit 2 activated
B1 = 1, B1 = 1 ---> Mode 4, lock bit 3 activated
(2)
(1)
Instruction
Format
Byte 1
1010 1100
1010 1100
0010 0000
0100 0000
1010 1100
0010 0100
0010 1000
0011 0000
0101 0000
Byte 2
0101 0011
100x xxxx
xxx
xxx
1110 00
xxxx xxxx
xxx
xxx
xxx
}
xxxx xxxx
Byte 3
xxxx xxxx
xxxx xxxx
xxxx xxxx
Byte 0
Byte 0
xxx xxxx
Each of the lock bits needs to be activated sequentially before
Mode 4 can be executed.
For Page Read/Write, the data always starts from byte 0 to
255. After the command byte and upper address byte are
latched, each byte thereafter is treated as data until all 256
bytes are shifted in/out. Then the next instruction will be
ready to be decoded.
Byte 4
xxxx xxxx
0110 1001
(Output)
xxxx xxxx
xxxx xxxx
xx
Signature Byte
Byte 1...
Byte 255
Byte 1...
Byte 255
xx
Operation
Enable Serial Programming
while RST is high
Chip Erase Flash memory
array
Read data from Program
memory in the byte mode
Write data to Program
memory in the byte mode
Write Lock bits. See Note (2).
Read back current status of
the lock bits (a programmed
lock bit reads back as a ‘1’)
Read Signature Byte
Read data from Program
memory in the Page Mode
(256 bytes)
Write data to Program
memory in the Page Mode
(256 bytes)
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