H8SXSLASH1663M datasheet(1191/1504 Pages) RENESAS

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Section 25 Flash Memory

Rev. 2.00 Sep. 24, 2008 Page 1159 of 1468

REJ09B0412-0200

In user boot mode, though the user boot MAT can be seen in the flash memory space, the user

MAT is hidden in the background. Therefore, the user MAT and user boot MAT are switched

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 programming completes, switch the memory MATs again to return to the first

state.

Memory MAT switching is enabled by setting FMATS. However note that access to a memory

MAT is not allowed until memory MAT switching is completed. During memory MAT switching,

the LSI is in an unstable state, e.g. if an interrupt occurs, from which memory MAT the interrupt

vector is read is undetermined. Perform memory MAT switching in accordance with the

description in section 25.11, Switching between User MAT and User Boot MAT.

Except for memory 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 procedure program (on-chip RAM, user MAT,

and external space) is shown in section 25.8.5, On-Chip Program and Storable Area for Program

Data.

H8SX/1663M Datasheet(PDF) 1191 Page - Renesas Technology Corp