at89c5131 ATMEL Corporation, at89c5131 Datasheet - Page 29

• Manufacturer Part Number: at89c5131
• Description: 8-bit Flash Microcontroller With Full Speed Usb Device At89c5131
• Manufacturer: ATMEL Corporation

Overview of FM0
Operations
Mapping of the Memory Space By default, the user space is accessed by MOVC instruction for read only. The column
Launching Programming
4136C–USB–04/05
The CPU interfaces to the Flash memory through the FCON register and AUXR1
register.
These registers are used to:
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•
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latches space is made accessible by setting the FPS bit in FCON register. Writing is
possible from 0000h to 7FFFh, address bits 6 to 0 are used to select an address within a
page while bits 14 to 7 are used to select the programming address of the page.
Setting this bit takes precedence on the EXTRAM bit in AUXR register.
The other memory spaces (user, extra row, hardware security) are made accessible in
the code segment by programming bits FMOD0 and FMOD1 in FCON register in accor-
dance with Table 34. A MOVC instruction is then used for reading these spaces.
Table 34. FM0 Blocks Select Bits
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
programming. This sequence is 5 followed by A. Table 35 summarizes the memory
spaces to program according to FMOD1:0 bits.
Table 35. Programming Spaces
Extra Row
Reserved
Security
Space
Map the memory spaces in the adressable space
Launch the programming of the memory spaces
Get the status of the Flash memory (busy/not busy)
Select the Flash memory FM0/FM1.
User
FMOD1
0
0
1
1
FPL3:0
A
A
A
A
5
5
5
5
FMOD0
FPS
0
1
0
1
Write to FCON
X
X
X
X
X
X
X
X
FMOD1
FM0 Adressable Space
User (0000h-FFFFh)
Extra Row(FF80h-FFFFh)
Hardware Security (0000h)
reserved
0
0
0
0
1
1
1
1
FMOD0
0
0
1
1
0
0
1
1
Operation
No action
Write the column latches in user
space
No action
Write the column latches in extra row
space
No action
Write the fuse bits space
No action
No action
AT89C5131
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