LM3S101 Data Sheet
March 22, 2006
88
Preliminary
Register 6: Flash Memory Control (FMC), offset 0x008
When this register is written, the flash controller initiates the appropriate access cycle for the
location specified by the
Flash Memory Address (FMA)
register (see page 86). If the access is a
write access, the data contained in the
Flash Memory Data (FMD)
register (see page 87) is
written.
This is the final register written and initiates the memory operation. There are four control bits in
the lower byte of this register that, when set, initiate the memory operation. The most used of
these register bits are the
ERASE
and
WRITE
bits.
It is a programming error to write multiple control bits and the results of such an operation are
unpredictable.
Bit/Field
Name
Type
Reset
Description
31:16
WRKEY
WO
0
This field contains a write key, which is used to minimize the
incidence of accidental flash writes. The value 0xA442 must
be written into this field for a write to occur. Writes to the
FMC
register without this WRKEY value are ignored. A
read of this field returns the value 0.
15:4
reserved
RO
0
Reserved bits return an indeterminate value, and should
never be changed.
3
COMT
R/W
0
Commit (write) of register value to non-volatile storage. A
write of 0 has no effect on the state of this bit.
If read, the state of the previous commit access is provided.
If the previous commit access is complete, a 0 is returned;
otherwise, if the commit access is not complete, a 1 is
returned.
This can take up to 50
μ
s.
2
MERASE
R/W
0
Mass erase flash memory
If this bit is set, the flash main memory of the device is all
erased. A write of 0 has no effect on the state of this bit.
If read, the state of the previous mass erase access is
provided. If the previous mass erase access is complete, a
0 is returned; otherwise, if the previous mass erase access
is not complete, a 1 is returned.
This can take up to 250 ms.
reserved
WO
0
Flash Memory Control (FMC)
Offset 0x008
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reset
Type
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
WO
RO
0
Reset
Type
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
R/W
R/W
R/W
R/W
COMT
WRKEY
MERASE ERASE
WRITE