EZ80F91MCU Datasheet, PDF (124/396 Pages) Zilog, Inc. – eZ80Acclaim-TM Flash Microcontrollers

eZ80F91 MCU
Product Specification
105
Flash Memory
Flash Memory Arrangement in the eZ80F91 Device
The eZ80F91 device features 256 KB (262,144 bytes) of nonvolative Flash mem-
ory with Read/Write/Erase capability. The main Flash memory array is arranged in
128 pages with 8 rows per page and 256 bytes per row. In addition to main Flash
memory, there are two separately-addressable rows which comprise a 512-byte
information page.
256 KB of main storage can be protected in eight 32 KB blocks. Protecting a 32 KB
block prevents Write or Erase operations. The lower 32 KB block (00000h–
07FFFh) can be protected using the external WP pin. This portion of memory is
called the Boot Block because the CPU always starts executing code from this
location at startup. If the application requires external program memory, then the
Boot Block must at least contain a jump instruction to move the Program Counter
outside of the Flash memory space.
The Flash memory arrangement is illustrated in Figure 22.
8
32 KB blocks
16
2 KB pages
per block
8
256-byte rows
per page
F
7
7
E
D
6
6
C
B
5
5
A
9
4
4
8
7
3
3
6
5
2
2
4
3
1
1
2
1
0
0
0
Figure 22. eZ80F91 Flash Memory Arrangement
256
single-byte columns
per row
255 254
10
PS019209-0504
PRELIMINARY
Flash Memory