FLASH MEMORY VERSION
19.1 Overview
19.1.3 Boot mode
When being reset with pin MD1 tied to Vcc level and pin MD0 to Vss level, the flash memory version enters
the boot mode. In the boot mode, the software in the boot ROM area is executed after reset.
In the boot mode, either the boot ROM area or the user ROM area can be selected with the user ROM
area select bit (bit 5 at address 9E16). The boot ROM area is located at addresses E00016 to FFFF16 in the
boot mode.
A reprogramming control firmware used in the flash memory serial I/O mode has been stored in the boot
ROM area on shipment. (Refer to section “19.3 Flash memory serial I/O mode.”) Therefore, when being
reset in the boot mode, the flash memory version enters the flash memory serial I/O mode, allowing the
user ROM area to be reprogrammed with a dedicated serial programmer.
Also the boot ROM area can be reprogrammed in the flash memory parallel I/O mode. If an appropriate
reprogramming control software using the CPU reprogramming mode has been stored in the boot ROM
area, reprogramming suitable for the user’s system is enabled.
Note that if the boot ROM area has been reprogrammed in the flash memory parallel I/O mode, the flash
memory serial I/O mode cannot be used.
7906 Group User’s Manual Rev.2.0
19-8
RENESAS [ RENESAS TECHNOLOGY CORP ]
