Z8 Encore! XP® F08xA Series
Product Specification
134
Flash Control Register Definitions
Flash Control Register
The Flash Controller must be unlocked using the Flash Control register before program-
ming or erasing the Flash memory. Writing the sequence 73H8CH, sequentially, to the
Flash Control register unlocks the Flash Controller. When the Flash Controller is
unlocked, the Flash memory can be enabled for Mass Erase or Page Erase by writing the
appropriate enable command to the FCTL. Page Erase applies only to the active page
selected in Flash Page Select register. Mass Erase is enabled only through the On-Chip
Debugger. Writing an invalid value or an invalid sequence returns the Flash Controller to
its locked state. The Write-only Flash Control Register shares its Register File address
with the read-only Flash Status Register
.
Table 79. Flash Control Register (FCTL)
BITS
7
6
5
4
3
2
1
0
FCMD
FF8H
FIELD
RESET
R/W
0
0
0
0
0
0
0
0
W
W
W
W
W
W
W
W
ADDR
FCMD—Flash Command
73H = First unlock command.
8CH = Second unlock command.
95H = Page Erase command (must be third command in sequence to initiate Page Erase).
63H = Mass Erase command (must be third command in sequence to initiate Mass Erase).
5EH = Enable Flash Sector Protect Register Access
Flash Status Register
The Flash Status register indicates the current state of the Flash Controller. This register
can be read at any time. The read-only Flash Status Register shares its Register File
address with the Write-only Flash Control Register.
Table 80. Flash Status Register (FSTAT)
BITS
7
6
5
4
3
2
1
0
Reserved
FSTAT
FIELD
RESET
0
0
0
0
0
0
0
0
PS024705-0405
P R E L I M I N A R Y
Flash Memory
ZILOG [ ZILOG, INC. ]
