SH7080_09 Datasheet, PDF (1338/1622 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family

Section 23 Flash Memory
<User MAT>
<On-chip RAM>
Procedure for
switching to the
user boot MAT
Procedure for
switching to
the user MAT
<User boot MAT>
Procedure for switching to the user boot MAT
(1) Mask interrupts.
(2) Write H'AA to FMATS.
(3) Execute four NOP instructions before
accessing the user boot MAT.
Procedure for switching to the user MAT
(1) Mask interrupts.
(2) Write a value other than H'AA to FMATS.
(3) Execute four NOP instructions before accessing
the user MAT.
Figure 23.20 Switching between User MAT and User Boot MAT
23.8.2 Interrupts during Programming/Erasing
(1) Download of On-Chip Program
(1.1) VBR setting change
Before downloading the on-chip program, VBR must be set to H'84000000. If VBR is set to a
value other than H'84000000, the interrupt vector table is placed in the user MAT (FMATS is
not H'AA) or the user boot MAT (FMATS is H'AA) on setting H'84000000 to VBR.
When VBR setting change conflicts with interrupt occurrence, whether the vector table before
or after VBR is changed is referenced may cause an error.
Therefore, for cases where VBR setting change may conflict with interrupt occurrence, prepare
a vector table to be referenced when VBR is H'00000000 (initial value) at the start of the user
MAT or user boot MAT.
(1.2) SCO download request and interrupt request
Download of the on-chip programming/erasing program that is initiated by setting the SCO bit
in FCCS to 1 generates a particular interrupt processing accompanied by MAT switchover.
Operation when the SCO download request and interrupt request conflicts is described below.
1. Contention between SCO download request and interrupt request
Figure 23.21 shows the timing of contention between execution of the instruction that sets
the SCO bit in FCCS to 1 and interrupt acceptance.
Rev. 4.00 Dec. 15, 2009 Page 1278 of 1558
REJ09B0181-0400