Setting The Mb91Fv360 To External Rom-Mode - Fujitsu FR Series Application Note

3 Setting the MB91FV360 to External ROM-mode

The MCU can be set to External-ROM mode only if mode data is read (at reset) from
external memory. Immediately after power-on, the MCU can't be set to external ROM mode
by one step. After power on the contents of the external SRAM is undefined. Invalid mode
data can set the MCU to an undefined mode. To avoid that invalid mode data are read at
reset, the MCU is set to internal ROM mode at first.
Then mode data can be set to a valid value and at the next reset the MCU can be set to the
external ROM mode.
The following steps (Figure 3) set the MCU to external ROM-mode and allow the loading of
the application to the emulation RAM of the Eva-board.
settings:
MD0-MD2 to GND (dipswitch S1:MD0-MD2 to ON)
action:
Start debugger
settings:
MD0 to VCC (dipswitch S1:MD0 to OFF)
action:
set mode data and reset vector
reset MCU in external memory
AN-910011-18
Chapter 3 Setting the MB91FV360 to External ROM-mode
Start
set MCU to internal ROM mode
MCU:
internal ROM mode
set MCU to external ROM mode
MCU:
external ROM
mode
Figure 3 sequence to set the MCU to external ROM mode
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