Datasheet

Section 7 ROM
Page 170 of 982 REJ09B0465-0300 Rev. 3.00
Sep 17, 2010
H8S/20103, H8S/20203, H8S/20223, H8S/20115, H8S/20215, H8S/20235 Group
7.5 On-Board Programming
The flash memory can be programmed/erased on board (boot mode and user mode), or by using a
PROM programmer (programmer mode). When the reset is released, this LSI enters one of these
modes depending on the levels of the signals input on the TEST, NMI, and ports, as shown in
table 7.3. The levels of these signals must be fixed at least 80 μs before the reset is released.
When this LSI enters boot mode, the built-in boot program is initiated. The boot program transfers
the programming-control program to the on-chip RAM, erases the flash memory areas entirely,
and then executes the programming-control program. Boot mode is useful for on-board initial
programming as well as forced recovery when programming/erasure in user mode is disabled.
User mode is useful for erasing and reprogramming the specified blocks, which function is
achieved by branching to the programming/erasure processing programs prepared by the user.
Table 7.3 Pin Levels and Programming Mode Selection
TEST NMI P85 PB3 PB2 PB1 PB0 LSI Modes after Release from a Reset
0 1 × × × × × User mode
0 0 1 × × × × Boot mode
1 × × 0 0 0 0 Programmer mode
Note: ×: Do not care.
7.5.1 Boot Mode
In boot mode, control commands and data for programming are transmitted from the externally
connected host via SCI3_1 to program/erase the user ROM area.
In boot mode, it is necessary to prepare the tool for transmitting control commands and data for
programming, and the data for programming in the host. Asynchronous mode is used for serial
communication. Figure 7.2 shows the system configuration in boot mode. Although interrupt
requests are ignored in boot mode, interrupt requests should be disabled by the system.