Datasheet

49
32133D–11/2011
UC3D
8.8.2 Flash Command Register
Name: FCMD
Access Type: Read/Write
Offset:0x04
Reset Value: 0x00000000
The FCMD can not be written if the flash is in the process of performing a flash command. Doing
so will cause the FCR write to be ignored, and the PROGE bit in FSR to be set.
• KEY: Write protection key
This field should be written with the value 0xA5 to enable the command defined by the bits of the register. If the field is written
with a different value, the write is not performed and no action is started.
This field always reads as 0.
• PAGEN: Page number
The PAGEN field is used to address a page or fuse bit for certain operations. In order to simplify programming, the PAGEN field
is automatically updated every time the page buffer is written to. For every page buffer write, the PAGEN field is updated with
the page number of the address being written to. Hardware automatically masks writes to the PAGEN field so that only bits
representing valid page numbers can be written, all other bits in PAGEN are always 0. As an example, in a flash with 1024
pages (page 0 - page 1023), bits 15:10 will always be 0.
31 30 29 28 27 26 25 24
KEY
23 22 21 20 19 18 17 16
PAGEN [15:8]
15 14 13 12 11 10 9 8
PAGEN [7:0]
76543210
-- CMD
Table 8-6. Semantic of PAGEN field in different commands
Command PAGEN description
No operation Not used
Write Page The number of the page to write
Clear Page Buffer Not used
Lock region containing given Page Page number whose region should be locked
Unlock region containing given Page Page number whose region should be unlocked
Erase All Not used
Write General-Purpose Fuse Bit GPFUSE #
Erase General-Purpose Fuse Bit GPFUSE #
Set Security Bit Not used