SH7146 Datasheet, PDF (829/1022 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperH™ RISC engine Family

Section 19 Flash Memory
The difference between the programming procedures in user program mode and user boot
mode is whether the MAT is switched or not as shown in figure 19.13.
In user boot mode, the user boot MAT can be seen in the flash memory space with the user
MAT hidden in the background. The user MAT and user boot MAT are switched only while
the user MAT is being programmed. Because the user boot MAT is hidden while the user
MAT is being programmed, the procedure program must be located in an area other than flash
memory. After programming finishes, switch the MATs again to return to the first state.
MAT switchover is enabled by writing a specific value to FMATS. However note that while
the MATs are being switched, the LSI is in an unstable state, e.g. access to a MAT is not
allowed until MAT switching is completely finished, and if an interrupt occurs, from which
MAT the interrupt vector is read from is undetermined. Perform MAT switching in accordance
with the description in section 19.8.1, Switching between User MAT and User Boot MAT.
Except for MAT switching, the programming procedure is the same as that in user program
mode.
The area that can be executed in the steps of the user procedure program (on-chip RAM, user
MAT, and external space) is shown in section 19.9.2, Areas for Storage of the Procedural
Program and Data for Programming.
Rev. 3.00 May 17, 2007 Page 785 of 974
REJ09B0229-0300