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Read protection can be combined with sector specific write protection. In this case, after
execution of the command 'Disable Read Protection' only those sectors are unlocked for
write accesses, which are not separately write protected.
5.6.5.2
Write and OTP Protection
If sector write protection is installed and active, erasing and programming of write
protected sectors is not possible. An installed write protection is indicated per user by the
three (because three users are supported) WPROIN bits in FSR register, and sector-
specific by the configuration status bits in the Protection Configuration registers
PROCON0 (for user 0), PROCON1 (for user 1) and PROCON2 (sectors of user 2 with
OTP protection, representing ROM functionality).
Note: Sectors in Data Flash cannot be separately write protected (only generally via
Read Protection).
Note: Beginning with sector S10, only sector-pairs of two 256 KB sectors can be defined
for installation of sector-specific write or OTP protection (see PROCON registers).
Note: An installation of OTP protection (for ROM functionality) can be performed only
once, because the UCB2 block is locked for ever after the installation.
Note: Full FAR test of protected Flash is only possible, if the customer has de-installed
the protection before, or if the passwords are known by the test person. In case of
OTP/ROM protection, the Flash test capability of FAR is very limited, because
FSI-SFRs and FSI-SRAM are no more accessible.
As read protection, installation of write protection is performed with the "Write User
Configuration Page" operation, controlled by the user. With this command, the user
defines and writes into the UCBx page 0 the write protection configuration bits for all
sectors, which shall be locked by the specific user, and the user-specific two keywords
(not necessary for user 2). The position of sector lock bits is identical as defined for the
PROCON registers. The correctness of keywords shall then (after next reset) be
checked with the command 'Disable Sector Write Protection', which delivers a protection
error PROER in case of wrong passwords. Only if the keywords are correct, the special
32-bit confirmation code must be written into the page 2 of UCBx with a second "Write
User Configuration Page" command. Only this confirmation code enables the write
protection of the User Control Block UCBx, and only in this case the installation bit(s) in
FSR is (are) set during rampup.
Note: If the write protection is configured in the user's UCB page 0 but not confirmed via
page 2 (necessary for check of keywords), the state after next reset is as follows:
- The selected sector(s) are protected (good for testing of protection, also of OTP)
- The UCBx is not protected, thus it can be erased without passwords
- The related WPROINx bit in FSR is not set
- The Disable Write Protection command sets the WPRODISx bit
- The Resume command does not clear the WPRODISx bit.
User's Manual
PMU, V1.47
Program Memory Unit (PMU)
5-67
TC1728
V1.0, 2011-12
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