at89c51re2-slsem ATMEL Corporation, at89c51re2-slsem Datasheet - Page 40

• Manufacturer Part Number: at89c51re2-slsem
• Description: At89c51re2 8-bit Flash Microcontroller
• Manufacturer: ATMEL Corporation

Launching flash commands
(activation sequence)
40
AT89C51RE2
Erase FM0
Reserved
Reserved
Column
Latches
Reset
HSB
FM0
XAF
FM0
FM0
FCB
FPL3:0 bits in FCON register are used to secure the launch of programming. A specific
sequence must be written in these bits to unlock the write protection and to launch the
operation. This sequence is 5xh followed by Axh. Table 25 summarizes the memory
spaces to program according to FMOD2:0 bits.
Table 25.
Note:
FPL3:0
A
A
A
A
A
A
A
A
5
5
5
5
5
5
5
5
1. The sequence 5xh and Axh must be executed without instructions between them oth-
2. The sequence 5xh and Axh can be executed with the differents FMOD0, FMOD1 val-
3. When the FMOD2 bit is set (coreesponding to the serial number field code) no write
4. Only the bits coresponding to the previously “full erase” memory space can be written
FM0
erwise the programming is not executed (see flash status register).
ues, the last FMOD1:0 value latches the destination target.
operation can be performed.
to one.
FPS
Programming Sequences
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Write to FCON
FMOD2
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
FMOD1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
FMOD0
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
Operation
No action
Write the column latches in FM0
No action
Write the column latches in FM0
extra row space
No action
Full erase FM0 memory area
No action
Reset the FM0 column latches
No action
Write the hardware Security byte
(HSB) See
No action
Write the Fuse Configuration Byte
(FCB)
No action
(4)
7663B–8051–03/07