Z8F042AHJ020SG Datasheet, PDF (170/282 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F082A Series
Product Specification
153
Flash Controller Behavior in DEBUG Mode
The following changes in behavior of the Flash Controller occur when the Flash Control-
ler is accessed using the On-Chip Debugger:
• The Flash Write Protect option bit is ignored.
• The Flash Sector Protect Register is ignored for programming and erase
operations.
• Programming operations are not limited to the page selected in the Page Select
Register.
• Bits in the Flash Sector Protect Register can be written to one or zero.
• The second write of the Page Select Register to unlock the Flash Controller is not
necessary.
• The Page Select Register can be written when the Flash Controller is unlocked.
• The Mass Erase command is enabled through the Flash Control Register.
Caution: For security reasons, the Flash controller allows only a single page to be opened for write/
erase. When writing multiple Flash pages, the flash controller must go through the unlock
sequence again to select another page.
Flash Control Register Definitions
This section defines the features of the following Flash Control registers.
Flash Control Register: see page 153
Flash Status Register: see page 155
Flash Page Select Register: see page 156
Flash Sector Protect Register: see page 157
Flash Frequency High and Low Byte Registers: see page 157
Flash Control Register
The Flash Controller must be unlocked using the Flash Control (FCTL) Register before
programming or erasing the Flash memory. Writing the sequence 73H 8CH, sequentially,
to the Flash Control Register unlocks the Flash Controller. When the Flash Controller is
unlocked, the Flash memory can be enabled for Mass Erase or Page Erase by writing the
appropriate enable command to the FCTL. Page Erase applies only to the active page
selected in Flash Page Select Register. Mass Erase is enabled only through the On-Chip
PS022827-1212
PRELIMINARY
Flash Control Register Definitions