TC1796
System Units (Vol. 1 of 2)
Program Memory Unit
User’s Manual 7-31 V2.0, 2007-07
PMU, V2.0
protection is hierarchically controlled. This means, if user 0 (assigned to UCB0) disables
write protection for his sector(s), also write protection for user 1 (assigned to UCB1) is
disabled but not vice versa (user 1 can only disable his own protected sectors).
Note: Sector specific write protection may be combined with read protection. In this
case, after execution of the Disable Sector Write Protection command the
protected sectors are only unlocked if read protection is also disabled.
Resumption of the temporarily disabled write protection (and read protection) is done by
sending the Resume Protection command or by executing a reset operation. For UCB2,
disabling write protection and thus re-programming is not possible.
The configuration of an installed write protection is indicated by:
• Three status flags FSR.WPROINx (x = 0-2) that indicate whether sector write
protection is installed for UCBx or not
• Status flag FSR.PROIN = 1; this bit is set coincidently with FSR.WPROINx
• Status flags SnL (n = 0-12) in the three Protection Configuration registers PROCONx
(x = 0-2) that indicate which Flash sectors are write-protected by UCBx
• The state of a write protection (enabled or temporarily disabled) is indicated by bits
FSR.WPRODIS0 (for UCB0) and FSR.WPRODIS1 (for UCB1).
After the execution of an Erase User Configuration Block command, which requires the
preceding disabling of an active write protection by the Disable Write Protection
command, all keywords and all protection parameters in the UCB are erased. Thus, the
UCB is totally unprotected until it becomes re-programmed. The only exception is UCB2,
which can never be erased after installation of OTP write protection.
If global write protection is additionally installed (implicitly with an installed read
protection), a Disable Read Protection command must be issued before the write
protection configuration parameters in UCB0 can be modified by user 0.
Note: All PFLASH sectors can be write-protected or OTP-protected, separately for all
three users. DFLASH sectors cannot be separately write-protected (only generally
via Read Protection).
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