C8051F300/1/2/3/4/5
92
Rev. 2.9
Accessing Flash
from user firmware
executing from an
unlocked page
:
1.
Any unlocked page except the page containing the Lock Byte may be read, written, or erased.
2.
Locked pages cannot be read, written, or erased. An erase attempt on the page containing the
Lock Byte will result in a Flash Error device reset.
3.
The page containing the Lock Byte cannot be erased.
It may be read or written only if it is
unlocked. An erase attempt on the page containing the Lock Byte will result in a Flash Error device
reset.
4.
Reading the contents of the Lock Byte is always permitted.
5.
Locking additional pages (changing ‘1’s to ‘0’s in the Lock Byte) is not permitted.
6.
Unlocking Flash pages (changing ‘0’s to ‘1’s in the Lock Byte) is not permitted.
7.
The Reserved Area cannot be read, written, or erased. Any attempt to access the reserved area,
or any other locked page, will result in a Flash Error device reset.
Accessing Flash
from user firmware
executing from a
locked page
:
1.
Any unlocked page except the page containing the Lock Byte may be read, written, or erased.
2.
Any locked page except the page containing the Lock Byte may be read, written, or erased. An
erase attempt on the page containing the Lock Byte will result in a Flash Error device reset.
3.
The page containing the Lock Byte cannot be erased.
It may only be read or written. An erase
attempt on the page containing the Lock Byte will result in a Flash Error device reset.
4.
Reading the contents of the Lock Byte is always permitted.
5.
Locking additional pages (changing ‘1’s to ‘0’s in the Lock Byte) is not permitted.
6.
Unlocking Flash pages (changing ‘0’s to ‘1’s in the Lock Byte) is not permitted.
7.
The Reserved Area cannot be read, written, or erased. Any attempt to access the reserved area,
or any other locked page, will result in a Flash Error device reset.
SFR Definition 10.1. PSCTL: Program Store R/W Control
Bits7–2: UNUSED: Read = 000000b, Write = don’t care.
Bit1:
PSEE: Program Store Erase Enable
Setting this bit (in combination with PSWE) allows an entire page of Flash program memory
to be erased. If this bit is logic 1 and Flash writes are enabled (PSWE is logic 1), a write to
Flash memory using the MOVX instruction will erase the entire page that contains the loca-
tion addressed by the MOVX instruction. The value of the data byte written does not matter.
0: Flash program memory erasure disabled.
1: Flash program memory erasure enabled.
Bit0:
PSWE: Program Store Write Enable
Setting this bit allows writing a byte of data to the Flash program memory using the MOVX
instruction. The Flash location should be erased before writing data.
0: Writes to Flash program memory disabled.
1: Writes to Flash program memory enabled; the MOVX instruction targets Flash memory.
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset Value
—
—
—
—
—
—
PSEE
PSWE
00000000
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
SFR Address:
0x8F
Summary of Contents for C8051F300
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