Z8F0123SB005EG Zilog, Z8F0123SB005EG Datasheet - Page 144

• Manufacturer Part Number: Z8F0123SB005EG
• Description: IC ENCORE MCU FLASH 1K 8SOIC
• Manufacturer: Zilog
• Series: Encore!® XP®r

Specifications of Z8F0123SB005EG

• Core Processor: Z8
• Core Size: 8-Bit
• Speed: 5MHz
• Connectivity: IrDA, UART/USART
• Peripherals: Brown-out Detect/Reset, LED, POR, PWM, WDT
• Number Of I /o: 6
• Program Memory Size: 1KB (1K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 4x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 105°C
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Other names: 269-3757

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PS024314-0308
Table 78. Flash Code Protection Using the Flash Option Bits
Flash Code Protection Using the Flash Controller
At Reset, the Flash Controller locks to prevent accidental program or erasure of the Flash
memory. To program or erase the Flash memory, first write the Page Select Register with
the target page. Unlock the Flash Controller by making two consecutive writes to the
Flash Control register with the values
must be rewritten with the same page previously stored there. If the two Page Select writes
do not match, the controller reverts to a locked state. If the two writes match, the selected
page becomes active. For more details, see
After unlocking a specific page, you can enable either Page Program or Erase. Writing the
value
protected. Any other value written to the Flash Control register locks the Flash Controller.
Mass Erase is not allowed in the user code but only in through the Debug Port.
After unlocking a specific page, you can also write to any byte on that page. After a byte is
written, the page remains unlocked, allowing for subsequent writes to other bytes on the
same page. Further writes to the Flash Control Register cause the active page to revert to a
locked state.
Sector Based Flash Protection
The final protection mechanism is implemented on a per-sector basis. The Flash memories
of Z8 Encore! XP devices are divided into maximum number of 8 sectors. A sector is 1/8
of the total size of the Flash memory, unless this value is smaller than the page size, in
which case the sector and page sizes are equal.
The Sector Protect Register controls the protection state of each Flash sector. This register
is shared with the Page Select Register. It is accessed by writing
the Flash controller. The next write to the Flash Control Register targets the Sector Protect
Register.
The Sector Protect Register is initialized to 0 on reset, putting each sector into an
unprotected state. When a bit in the Sector Protect Register is written to 1, the
corresponding sector can no longer be written or erased by the CPU. External Flash pro-
gramming through the OCD or via the Flash Controller Bypass mode are unaffected. After
FWP
0
1
95H
Flash Code Protection Description
Programming and erasing disabled for all of Flash Program Memory. In user
code programming, Page Erase, and Mass Erase are all disabled. Mass Erase
is available through the On-Chip Debugger.
Programming, Page Erase, and Mass Erase are enabled for all of Flash
Program Memory.
causes a Page Erase only if the active page resides in a sector that is not
73H
and
Figure
8CH
, sequentially. The Page Select Register
21.
Z8 Encore! XP
Product Specification
73H
followed by
®
F0823 Series
Flash Memory
5EH
to
134