C8051F2XX Datasheet, PDF (87/146 Pages) Silicon Laboratories – Mixed Signal 8 kB ISP Flash MCU Family

C8051F2xx
Program Memory
Space
(This Block locked only if all
other blocks are locked)
Reserved
Read Lock Byte
Write/Erase Lock Byte
0x207F
0x2000
0x1FFF
0x1E00
0x1DFF
0x1DF
E
0x1DFD
Software Read Limit
0x0000
Read and Write/Erase Security Bits.
(Bit 7 is MSB.)
Bit Memory Block
7 0x1C00 - 0x1DFD
6 0x1800 - 0x1BFF
5 0x1400 - 0x17FF
4 0x1000 - 0x13FF
3 0x0C00 - 0x0FFF
2 0x0800 - 0x0BFF
1 0x0400 - 0x07FF
0 0x0000 - 0x03FF
Flash Read Lock Byte
Bits7–0: Each bit locks a corresponding block of memory. (Bit 7 is MSB.)
0: Read operations are locked (disabled) for corresponding block across the JTAG inter-
face.
1: Read operations are unlocked (enabled) for corresponding block across the JTAG inter-
face.
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.
Flash Access Limit Register (FLACL)
The content of this register is used as the high byte of the 16-bit software read limit
address. The 16-bit read limit address value is calculated as 0xNN00 where NN is
replaced by content of this register on reset. Software running at or above this address is
prohibited from using the MOVX and MOVC instructions to read, write, or erase, locations
below this address. Any attempts to read locations below this limit will return the value
0x00.
Figure 10.1. Flash Program Memory Security Bytes
The lock bits can always be read and cleared to logic 0 regardless of the security setting applied to the
block containing the security bytes. This allows additional blocks to be protected after the block containing
the security bytes has been locked. However, the only means of removing a lock once set is to erase the
entire program memory space by performing a JTAG erase operation. NOTE: Erasing the Flash memory
block containing the security bytes will automatically initiate erasure of the entire program memory space
(except for the reserved area). This erasure can only be performed via the JTAG. If a non-security byte in
the 0x1C00–0x1DFF page is written to in order to perform an erasure of that page, then that page including
the security bytes will be erased.
Rev. 1.6
87