Renesas H8S Series Hardware Manual page 829

Section 21 Flash Memory (0.18-µm F-ZTAT Version)
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 21.14.
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 executed in an area other than flash memory. After
the programming procedure completes, switch the MATs again to return to the first state.
MAT switching is enabled by writing a specific value to FMATS. Note however 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 completed, and if an interrupt occurs, from which MAT the interrupt vector is
read is undetermined. Perform MAT switching in accordance with the description in section 21.6,
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 and user
MAT) is shown in section 21.4.4, Storable Areas for Procedure Program and Program Data.
Rev. 3.00 Jul. 14, 2005 Page 781 of 986
REJ09B0098-0300