HD6473032F16 Datasheet, PDF (608/847 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

Section 18 ROM
On-Chip RAM Area Divisions in Boot Mode: In boot mode, the RAM area is divided into an
area used by the boot program and an area to which the programming control program is
transferred via the SCI, as shown in figure 18.8. The boot program area cannot be used until the
execution state in boot mode switches to the programming control program transferred from the
host.
Boot program area
H'FFDF10
H'FFE70F
H'FFE710
Programming
control
program area
H'FFFF0F
Figure 18.8 RAM Areas in Boot Mode
Notes: 1. The boot program area cannot be used until a transition is made to the execution state
for the programming control program transferred to RAM. Note also that the boot
program remains in this area of the on-chip RAM even after control branches to the
programming control program.
2. In flash memory emulation by RAM, part (H'FE000 to H'FEFFF) of the user program
transfer area is used as the area in which emulation is performed, and therefore the user
program must not be transferred to this area.
Notes on Using the Boot Mode
1. When this LSI comes out of reset in boot mode, it measures the low period the input at the
SCI’s RXD₁ pin. The reset should end with RXD₁ high. After the reset ends, it takes about 100
states for this LSI to get ready to measure the low period of the RXD₁ input.
2. If any data has been written to the flash memory (if all data is not H'FF), all flash memory
blocks are erased when this mode is executed. Therefore, boot mode should be used for initial
on-board programming, or for forced recovery if the program to be activated in user program
mode is accidentally erased and user program mode cannot be executed, for example.
3. Interrupts cannot be used during programming or erasing of flash memory.
4. The RXD₁ and TXD₁ pins should be pulled up on the board.
Rev. 3.00 Mar 21, 2006 page 578 of 814
REJ09B0302-0300