Z8F042AHJ020SC00TR Zilog, Z8F042AHJ020SC00TR Datasheet - Page 157

• Manufacturer Part Number: Z8F042AHJ020SC00TR
• Description: IC ENCORE XP MCU FLASH 4K 28SSOP
• Manufacturer: Zilog
• Series: Encore!® XP®r

Specifications of Z8F042AHJ020SC00TR

• Core Processor: Z8
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: IrDA, UART/USART
• Peripherals: Brown-out Detect/Reset, LED, LVD, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 23
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 28-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: Z8F042AHJ020SC00T

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PS022825-0908
Table 77. 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 target page. If the two Page Select writes do not match, the con-
troller reverts to a locked state. If the two writes match, the selected page becomes active.
See
After unlocking a specific page, you can enable either Page Program or Erase. Writing the
value
tected. 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!
of the Flash memory, unless this value is smaller than the page size, in which case the sec-
tor 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 73H followed by 5EH to
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 correspond-
ing sector is no longer written or erased by the CPU. External Flash programming through
FWP
0
1
Figure 22
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 pro-
®
on page 144 for details.
devices are divided into at most 8 sectors. A sector is 1/8 of the total size
73H
and
8CH
, sequentially. The Page Select Register
Z8 Encore! XP
Product Specification
®
F082A Series
Flash Memory
146