Boot Mode - Renesas F-ZTAT H8 Series Hardware Manual

6.4.1

Boot Mode

To use boot mode, a user program for programming and erasing the flash memory must be
provided in advance in the host. SCI3 is used in asynchronous mode.
When a reset start is executed after the chip's pins have been set to boot mode, the built-in boot
program is activated, and the programming control program provided in the host is transferred
sequentially to the chip using SCI3. The chip writes the programming control program received
via SCI3 to the programming control program area in the on-chip RAM. After the transfer is
completed, execution branches to the start address (H'FB80) of the programming control program
area, and the programming control program execution state is entered (flash memory
programming is performed).
Therefore, a routine conforming to the programming algorithm described later must be provided in
the programming control program transferred from the host.
Figure 6.7 shows the system configuration in boot mode, and figure 6.8 shows the boot mode
execution procedure.
Host
Figure 6.7 System Configuration when Using Boot Mode
Reception of
programming data
Transmission of verify data
H8/3857F
H8/3854F
Flash memory
RXD
SCI3
On-chip RAM
TXD
Rev.3.00 Jul. 19, 2007 page 133 of 532
6. ROM
REJ09B0397-0300