SH7055S Datasheet, PDF (831/1002 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7000 Series

<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 22.20 Switching between User MAT and User Boot MAT
22.8.2 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'00000000 (initial value). If
VBR is set to a value other than the initial value, 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 initialization of
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 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 22.21 shows the timing of contention between execution of the instruction that sets the
SCO bit in FCCS to 1 and interrupt acceptance.
Rev.2.0, 07/03, page 793 of 960