User Boot Mode - Renesas H8SX/1520 Series Hardware Manual

In figure 17.13, since RAM emulation is performed, the erasing/programming program is
downloaded to avoid the 4-kbyte on-chip RAM area (H'FFA000 to H'FFAFFF). Download and
initialization are performed only once at the beginning. Note the following when executing the
procedure program.
• Be careful not to overwrite data in the on-chip RAM with overlay settings. In addition to the
programming program area, erasing program area, and RAM emulation area, areas for the
procedure programs, work area, and stack area are reserved in the on-chip RAM. Do not make
settings that will overwrite data in these areas.
• Be sure to initialize both the programming program and erasing program. When the FPEFEQ
parameter is initialized, also initialize both the erasing program and programming program.
Initialization must be executed for both entry addresses: 32 bytes after #DLTOP (start address
of download destination for erasing program), and 32 bytes after #DLTOP (start address of
download destination for programming program).
17.8.3

User Boot Mode

Branching to a programming/erasing program prepared by the user enables user boot mode which
is a user-arbitrary boot mode to be used.
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)
Initiation in User Boot Mode
When the reset start is executed with the mode pins set to user boot mode, the built-in check
routine runs and checks the user MAT and user boot MAT states. 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, the user boot MAT
is selected (FMATS = H'AA) as the execution memory MAT.
(2)
User MAT Programming in User Boot Mode
Figure 17.14 shows the procedure for programming the user MAT in user boot mode.
The difference between the programming procedures in user program mode and user boot mode is
the memory MAT switching as shown in figure 17.14. For programming the user MAT in user
boot mode, additional processing made by setting FMATS is required: switching from the user
boot MAT to the user MAT, and switching back to the user boot MAT after programming
completes.
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Section 17 Flash Memory (0.18-(m F-ZTAT Version)
Rev. 3.00 Mar. 14, 2006 Page 613 of 804
REJ09B0104-0300