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Flash Module Control Registers
PRELIMINARY
2-9
Flash Operations and Control Registers
PRELIMINARY
Table 2–3. Segment Control Register Field Descriptions
Bits Name Description
15–8 SEG7–SEG0 Segment enable bits. Each of these bits protects the specified segment against pro-
gramming or enables programming for the specified segment in the array. Any number
of segments (from 0 to 7 in any combination) can be enabled at any one time. See
Table 2–4 for segment address ranges. EXE must be cleared to modify the SEGx bits.
SEGx = 1 enables programming of the corresponding segment.
SEGx = 0 protects the segment from programming.
7 Reserved This bit is not affected by writes, and reads of this bit are undefined.
6–5 KEY1, KEY0 Execute key bits. A binary value of 10 must be written to these bits in the same DSP
core access in which the EXE bit is set for the selected operation (erase, program, or
flash-write) to start. KEY1 and KEY0 must be cleared in the same write access that
clears EXE. These bits are used as additional protection against inadvertent program-
ming or erasure of the array. These bits are read as 0s.
4–3 VER0, VER1 Verify bits. These bits select special read modes used to verify proper erasure or pro-
gramming.
Possible values:
00: Normal read mode
01: Verify 1s (VER1) read mode to verify margin of 1s for proper erasure
10: Verify 0s (VER0) read mode to verify margin of 0s for proper programming
11: Inverse-read mode; tests for bits erased into depletion
2–1 WRITE/ERASE Write/erase enable field. These bits select the program, erase, or flash-write operation.
However, modification of the array data does not actually start until the EXE bit is set.
Reset clears these bits to zero.
Possible values:
00: Read operation is enabled. These bit values are required to read the array.
01: Erase operation is enabled
10: Write operation is enabled
11: Flash-write operation is enabled
0
EXE Execute bit. In conjunction with WRITE/ERASE, KEY1, and KEY0, this bit controls the
program, erase, and flash-write operations. Setting EXE starts and stops program-
ming and erasing of the flash array. The KEY1 and KEY0 bits must be written in the
same write access that sets EXE, and EXE must be cleared in the same write access
that clears KEY1 and KEY0. EXE must be cleared to modify the SEGx bits.
Note: The segment enable bits are not intended for protection during the erase or flash-write operations. During these opera-
tions,
all
segments must be enabled.