Z8F042ASJ020EG2156 Datasheet, PDF (172/280 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F082A Series
Product Specification
157
Flash Sector Protect Register
The Flash Sector Protect (FPROT) Register is shared with the Flash Page Select Register.
When the Flash Control Register is written with 5EH, the next write to this address targets
the Flash Sector Protect Register. In all other cases, it targets the Flash Page Select Regis-
ter.
This register selects one of the 8 available Flash memory sectors to be protected. The reset
state of each Sector Protect bit is an unprotected state. After a sector is protected by setting
its corresponding register bit, it cannot be unprotected (the register bit cannot be cleared)
without powering down the device.
Table 83. Flash Sector Protect Register (FPROT)
Bit
Field
RESET
R/W
Address
7
SPROT7
0
R/W
6
SPROT6
0
R/W
5
SPROT5
0
R/W
4
3
SPROT4 SPROT3
0
0
R/W
R/W
FF9H
2
SPROT2
0
R/W
1
SPROT1
0
R/W
0
SPROT0
0
R/W
Bit
Description
[7:0]
Sector Protection
SPROTn Each bit corresponds to a 1024-byte Flash sector on devices in the 8K range, while the
remaining devices correspond to a 512-byte Flash sector. To determine the appropriate Flash
memory sector address range and sector number for your Z8F082A Series product, please
refer to Table 78 on page 146 and to Figure 21, which follows the table.
• For Z8F08xA and Z8F04xA devices, all bits are used.
• For Z8F02xA devices, the upper 4 bits are unused.
• For Z8F01xA devices, the upper 6 bits are unused.
Flash Frequency High and Low Byte Registers
The Flash Frequency High (FFREQH) and Low Byte (FFREQL) registers combine to
form a 16-bit value, FFREQ, to control timing for Flash program and erase operations.
The 16-bit binary Flash Frequency value must contain the system clock frequency (in
kHz) and is calculated using the following equation:
FFREQ[15:0]
=
 FFREQH[7:0],FFREQL[7:0] 
=
S_----y_--s_---t_-e_---m_------C_---l_-o_---c_---k_---F_----r_-e_---q_---u_---e_--n_---c_---y_-
1000
PS022828-0413
PRELIMINARY
Flash Control Register Definitions