Table of Contents
Advertisement
20.2.2
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 20-2. 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.
* 1
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, FWE = 1, P16 = 0, PF0 = 1
MD1 = 1,
MD2 = 1,
FWE = 0
RES = 0
MD1 = 1,
MD2 = 1,
FWE = 1
* 1
User
Figure 20-2 Flash Memory State Transitions
Reset state
RES = 0
MD1 = 1
RES = 0
MD2 = 0,
FWE = 1
Boot mode
RES = 0
* 2
Programmer
mode
659
Advertisement
Table of Contents
