Datasheet

Section 21 ROM (Mask ROM Version, H8S/2138 F-ZTAT, H8S/2134 F-ZTAT, and H8S/2132 F-ZTAT)
Rev. 4.00 Jun 06, 2006 page 594 of 1004
REJ09B0301-0400
21.6.1 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 the H8S/2138 or H8S/2134 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 21.7, and the boot program mode
execution procedure in figure 21.8.
RxD1
TxD1
SCI1
The chip
Flash memory
Write data reception
Verify data transmission
Host
On-chip RAM
Figure 21.7 System Configuration in Boot Mode