Z8F640x/Z8F480x/Z8F320x/Z8F240x/Z8F160x
Z8 Encore!
®
143
Caution:
The byte at each address of the Flash memory cannot be programmed (any
bits written to 0) more than twice before an erase cycle occurs.
Page Erase
The Flash memory can be erased one page (512 bytes) at a time. Page Erasing the Flash
memory sets all bytes in that page to the value FFH. The Flash Page Select register identi-
fies the page to be erased. With the Flash Controller unlocked, writing the value
95H
to the
Flash Control register initiates the Page Erase operation. While the Flash Controller exe-
cutes the Page Erase operation, the eZ8 CPU idles but the system clock and on-chip
peripherals continue to operate. The eZ8 CPU resumes operation after the Page Erase
operation completes. If the Page Erase operation is performed through the On-Chip
Debugger, poll the Flash Status register to determine when the Page Erase operation is
complete. When the Page Erase is complete, the Flash Controller returns to its locked
state.
Mass Erase
The Flash memory can also be Mass Erased using the Flash Controller. Mass Erasing the
Flash memory sets all bytes to the value
FFH
. With the Flash Controller unlocked, writing
the value
63H
to the Flash Control register initiates the Mass Erase operation. While the
Flash Controller executes the Mass Erase operation, the eZ8 CPU idles but the system
clock and on-chip peripherals continue to operate. Typically, the Flash Memory is Mass
Erased using the On-Chip Debugger. Via the On-Chip Debugger, poll the Flash Status reg-
ister to determine when the Mass Erase operation is complete. Although the Flash can be
Mass Erased by user program code, when the Mass Erase is complete the user program
code is completely erased. When the Mass Erase is complete, the Flash Controller returns
to its locked state.
Flash Controller Bypass
The Flash Controller can be bypassed and the control signals for the Flash memory
brought out to the GPIO pins. Bypassing the Flash Controller allows faster Row Program-
ming algorithms by controlling the Flash programming signals directly.
Row programing is recommended for gang programming applications and large volume
customers who do not require in-circuit initial programming of the Flash memory. Mass
Erase and Page Erase operations are also supported when the Flash Controller is bypassed.
Please refer to the document entitled
Third-Party Flash Programming Support for Z8
Encore!™
for more information on bypassing the Flash Controller. This document is
available for download at
www.zilog.com.
PS017610-0404
Flash Memory
ZILOG [ ZILOG, INC. ]
