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22.2.2
Mode Transitions
When the mode pins and the FWE pin are set in the reset state and a reset-start is executed, the
microcomputer enters an operating mode as shown in figure 22-2. In user mode, flash memory can
be read but not programmed or erased.
The boot, user program and programmer modes are provided as modes to write and erase the flash
memory.
User mode
(on-chip ROM
enabled)
FWE = 1
FWE = 0
program mode
On-board programming mode
Notes: Only make a transition between user mode and user program mode when the CPU is
not accessing the flash memory.
1. RAM emulation possible
2. MD0 = 0, MD1 = 0, MD2 = 0, P14 = 0, P16 = 0, PF0 = 1
MD1 = 1,
MD2 = 1,
FWE = 0
* 1
RES = 0
MD1 = 1,
MD2 = 1,
FWE = 1
* 1
User
Figure 22-2 Flash Memory State Transitions
Reset state
RES = 0
MD1 = 0,
RES = 0
MD2 = 0,
FWE = 1
Boot mode
RES = 0
* 2
Programmer
mode
783
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