ZLF645 MAXIM [Maxim Integrated Products], ZLF645 Datasheet - Page 179

• Manufacturer Part Number: ZLF645
• Description: Flash MCUs with Learning Amplification
• Manufacturer: MAXIM [Maxim Integrated Products]

Flash Option Bits
19-4572; Rev 0; 4/09
Operation
Option Bit Shadow Register Loading By Reset
Programmable Flash Option Bits allow user configuration of certain aspects of ZLF645
MCU functionality. This configuration data is stored in the Flash memory Information
Block and then read into option byte shadow registers during the last portion of the
ZLF645 MCUs reset period.
Features available for control through the Flash Option Bits include:
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For each Flash memory option bit, there is an associated option bit shadow register that is
used to register the value of the option bit. The output of the option bit shadow registers
are used by the ZLF645 MCU to enable various features and functions for the ZLF645
MCU. Each time the Flash Memory Information Block Option Bits are programmed or
erased, the device must be reset for the change in ZLF645 configuration to take effect.
A POR or Stop Mode Recovery Reset with SMR bit 5 set to 1, loads the option bits from
the Flash memory to the Option Bit Shadow registers during the last few clock cycles of
the reset period. In some cases, in order to provide a required value before being loaded,
the Option Bit Shadow registers are reset to a predefined value on the start of the reset
period.
Port 0 low nibble pull-ups
Port 0 high nibble pull-ups
Port 1 low nibble pull-ups
Port 1 high nibble pull-ups
Port 2 pull-ups
Port 3 low nibble pull-ups
Port 4 pull-ups
WDT always enabled
Flash protect entire main memory
Flash protect lower half main memory
XTAL1 to System Clock (no division enable)
16-bit Stack addressiblity enable
ZLF645 Series Flash MCUs
Product Specification
Flash Option Bits
171