Z8F64220100ZDA Zilog, Z8F64220100ZDA Datasheet - Page 196
Manufacturer Part Number
ADAPTER ICE Z8 ENCORE 64K 64LQFP
Specifications of Z8F64220100ZDA
For Use With/related Products
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Flash Read Protection
Flash Write/Erase Protection
Timing Using the Flash Frequency Registers
Before performing a program or erase operation on the Flash memory, you must first
configure the Flash Frequency High and Low Byte registers. The Flash Frequency
registers allow programming and erasure of the Flash with system clock frequencies
ranging from 20 kHz through 20 MHz (the valid range is limited to the device operating
The Flash Frequency High and Low Byte registers combine to form a 16-bit value,
FFREQ, to control timing for Flash program and erase operations. The 16-bit Flash
Frequency value must contain the system clock frequency in kHz. This value is calculated
using the following equation:.
The user code contained within the Flash memory can be protected from external access.
Programming the Flash Read Protect Option Bit prevents reading of user code by the On-
Chip Debugger or by using the Flash Controller Bypass mode. For more information, see
The Z8 Encore! XP
tal program and erasure of the Flash memory contents. This protection is provided by the
Flash Controller unlock mechanism, the Flash Sector Protect register, and the Flash Write
Protect option bit.
Flash Controller Unlock Mechanism
At Reset, the Flash Controller locks to prevent accidental program or erasure of the Flash
memory. To program or erase the Flash memory, the Flash controller must be unlocked.
After unlocking the Flash Controller, the Flash can be programmed or erased. Any value
written by user code to the Flash Control register or Page Select Register out of sequence
will lock the Flash Controller.
Follow the steps below to unlock the Flash Controller from user code:
1. Write 00H to the Flash Control register to reset the Flash Controller.
2. Write the page to be programmed or erased to the Page Select register.
Flash programming and erasure are not supported for system clock frequencies
below 20 kHz, above 20 MHz, or outside of the device operating frequency
range. The Flash Frequency High and Low Byte registers must be loaded with
the correct value to insure proper Flash programming and erase operations.
on page 191 and
F64XX Series provides several levels of protection against acciden-
System Clock Frequency (Hz)
on page 195.
Z8 Encore! XP