AT32UC3C1512C Automotive Atmel Corporation, AT32UC3C1512C Automotive Datasheet - Page 257

• Manufacturer Part Number: AT32UC3C1512C Automotive
• Manufacturer: Atmel Corporation

15.4.9
9166C–AVR-08/11
Writing Words to a Page that is not Completely Erased
Figure 15-3. Mapping from Page Buffer to Flash
The page buffer is word-addressable and should only be written with aligned word transfers,
never with byte or halfword transfers. The page buffer can not be read.
The page buffer is also used for writes to the User page.
Page buffer write operations are performed with 4 wait states. Any accesses attempted to the
FLASHC on the HSB bus during these cycles will be automatically stalled.
Writing to the page buffer can only change page buffer bits from one to zero, i.e. writing
0xAAAAAAAA to a page buffer location that has the value 0x00000000 will not change the page
buffer value. The only way to change a bit from zero to one is to erase the entire page buffer with
the Clear Page Buffer command.
The page buffer is not automatically reset after a page write. The programmer should do this
manually by issuing the Clear Page Buffer flash command. This can be done after a page write,
or before the page buffer is loaded with data to be stored to the flash page.
This can be used for EEPROM emulation, i.e. writes with granularity of one word instead of an
entire page. Only words that are in an completely erased state (0xFFFFFFFF) can be changed.
The procedure is as follows:
6 3
5 9
5 5
5 1
4 7
4 3
3 9
3 5
3 1
2 7
2 3
1 9
1 5
1 1
7
3
A ll lo c a tio n s a re w o rd lo c a tio n s
P a g e B u ffe r
6 2
5 8
5 4
5 0
4 6
4 2
3 8
3 4
3 0
2 6
2 2
1 8
1 4
1 0
3 2 -b it d a ta
6
2
6 1
5 7
5 3
4 9
4 5
4 1
3 7
3 3
2 9
2 5
2 1
1 7
1 3
9
5
1
6 0
5 6
5 2
4 8
4 4
4 0
3 6
3 2
2 8
2 4
2 0
1 6
1 2
8
4
0
Y 6 3
Y 5 9
Y 5 5
Y 5 1
Y 4 7
Y 4 3
Y 3 9
Y 3 5
Y 3 1
Y 2 7
Y 2 3
Y 1 9
Y 1 5
Y 1 1
X 6 3
X 5 9
X 5 5
X 5 1
X 4 7
X 4 3
X 3 9
X 3 5
X 3 1
X 2 7
X 2 3
X 1 9
X 1 5
X 1 1
Y 7
Y 3
X 7
X 3
Y 6 2
Y 5 8
Y 5 4
Y 5 0
Y 4 6
Y 4 2
Y 3 8
Y 3 4
Y 3 0
Y 2 6
Y 2 2
Y 1 8
Y 1 4
Y 1 0
X 6 2
X 5 8
X 5 4
X 5 0
X 4 6
X 4 2
X 3 8
X 3 4
X 3 0
X 2 6
X 2 2
X 1 8
X 1 4
X 1 0
Y 6
Y 2
X 6
X 2
P a g e Y
P a g e X
F la s h
Y 6 1
Y 5 7
Y 5 3
Y 4 9
Y 4 5
Y 4 1
Y 3 7
Y 3 3
Y 2 9
Y 2 5
Y 2 1
Y 1 7
Y 1 3
X 6 1
X 5 7
X 5 3
X 4 9
X 4 5
X 4 1
X 3 7
X 3 3
X 2 9
X 2 5
X 2 1
X 1 7
X 1 3
Y 9
Y 5
Y 1
X 9
X 5
X 1
AT32UC3C
Y 6 0
Y 5 6
Y 5 2
Y 4 8
Y 4 4
Y 4 0
Y 3 6
Y 3 2
Y 2 8
Y 2 4
Y 2 0
Y 1 6
Y 1 2
X 6 0
X 5 6
X 5 2
X 4 8
X 4 4
X 4 0
X 3 6
X 3 2
X 2 8
X 2 4
X 2 0
X 1 6
X 1 2
Y 8
Y 4
Y 0
X 8
X 4
X 0
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