Datasheet

Section 21 Flash Memory
Rev. 2.00 Sep. 28, 2009 Page 689 of 870
REJ09B0429-0200
21.4.3 User Boot Mode
This LSI has user boot mode which is initiated with different mode pin settings than those in boot
mode or user program mode. User boot mode is a user-arbitrary boot mode, unlike boot mode that
uses the on-chip SCI.
Only the user MAT can be programmed/erased in user boot mode. Programming/erasing of the
user boot MAT is only enabled in boot mode or programmer mode.
(1) User Boot Mode Initiation
For the mode pin settings to start up user boot mode, see table 21.5.
When the reset start is executed in user boot mode, the built-in check routine runs. The user MAT
and user boot MAT states are checked by this check routine.
While the check routine is running, NMI and all other interrupts cannot be accepted.
Next, processing starts from the execution start address of the reset vector in the user boot MAT.
At this point, H′AA is set to FMATS because the execution MAT is the user boot MAT.
(2) User MAT Programming in User Boot Mode
For programming the user MAT in user boot mode, additional processing made by setting FMATS
are required: switching from user-boot-MAT selection state to user-MAT selection state, and
switching back to user-boot-MAT selection state after programming completes.
Figure 21.14 shows the procedure for programming the user MAT in user boot mode.