Datasheet

Section 22 ROM (Mask ROM Version, H8S/2148 F-ZTAT, H8S/2147N F-ZTAT, H8S/2144 F-ZTAT, and H8S/2142 F-ZTAT)
Rev. 4.00 Sep 27, 2006 page 656 of 1130
REJ09B0327-0400
22.6.1 Boot Mode
When boot mode is used, the flash memory programming control program must be prepared in the
host beforehand. The channel 1 SCI to be used is set to asynchronous mode.
When a reset-start is executed after this group MCU’s pins have been set to boot mode, the boot
program built into the MCU is started and the programming control program prepared in the host
is serially transmitted to the MCU via the SCI. In the MCU, the programming control program
received via the SCI is written into the programming control program area in on-chip RAM. After
the transfer is completed, control branches to the start address of the programming control
program area and the programming control program execution state is entered (flash memory
programming is performed).
The transferred programming control program must therefore include coding that follows the
programming algorithm given later.
The system configuration in boot mode is shown in figure 22.7, and the boot program mode
execution procedure in figure 22.8.
RxD1
TxD1
SCI1
This group chip
Flash memory
Write data reception
Verify data transmission
Host
On-chip RAM
Figure 22.7 System Configuration in Boot Mode