Figure 16.2. Flash Program Memory Map And Security Bytes - Silicon Laboratories C8051F120 Manual

Figure 16.2. FLASH Program Memory Map and Security Bytes

Read and Write/Erase Security Bits.
(Bit 7 is MSB.)
Bit Memory Block
7 0x1C000 - 0x1FBFD
6 0x18000 - 0x1BFFF
5 0x14000 - 0x17FFF
4 0x10000 - 0x13FFF
3 0x0C000 - 0x0FFFF
2 0x08000 - 0x0BFFF
1 0x04000 - 0x07FFF
0 0x00000 - 0x03FFF
FLASH Read Lock Byte
Bits7-0: Each bit locks a corresponding block of memory. (Bit7 is MSB).
0: Read operations are locked (disabled) for corresponding block across the JTAG interface.
1: Read operations are unlocked (enabled) for corresponding block across the JTAG interface.
FLASH Write/Erase Lock Byte
Bits7-0: Each bit locks a corresponding block of memory.
0: Write/Erase operations are locked (disabled) for corresponding block across the JTAG interface.
1: Write/Erase operations are unlocked (enabled) for corresponding block across the JTAG interface.
NOTE: When the highest block is locked, the security bytes may be written but not erased.
FLASH access Limit Register (FLACL)
The content of this register is used as the 8 MSBs of the 17-bit software read limit address. Software
running at or above this address is prohibited from using the MOVX and MOVC instructions to read,
write, or erase FLASH locations below this address. Any attempts to read locations below this limit
will return indeterminate data.
The lock bits can always be read and cleared to logic 0 regardless of the security setting applied to the block contain-
ing the security bytes. This allows additional blocks to be protected after the block containing the security bytes has
been locked. Important Note: The only means of removing a lock once the MSB of the write/erase lock security
byte is set is to erase the entire program memory space by performing a JTAG erase operation (i.e. cannot be
done in user firmware). Addressing either security byte while performing a JTAG erase operation will auto-
matically initiate erasure of the entire program memory space (except for the reserved area). This erasure can
only be performed via JTAG. If a non-security byte in the 0x1F800-0x1FBFF page is addressed during the
JTAG erasure, only that page (including the security bytes) will be erased.
C8051F120/1/2/3/4/5/6/7
SFLE = 0
0x1FFFF
Reserved
0x1FC00
Read Lock Byte
0x1FBFF
Write/Erase Lock Byte
0x1FBFE
0x1FBFD
Software Read Limit
0x00000
Rev. 1.2
SFLE = 1
0x00FF
Scratchpad Memory
(Data only)
0x0000
Program/Data
Memory Space
189