Z8 Encore! XP
®
4K Series
Product Specification
147
SPROT7-SPROT0—Sector Protection
Each bit corresponds to a 512 byte Flash sector. For the Z8F04xx devices all bits are used.
For the Z8F02xx devices, the upper 4 bits are unused. For the Z8F01xx 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:.
System Clock Frequency
FFREQ[15:0] =
{
FFREQH[7:0],FFREQL[7:0]
}
= --------------------------------------------------------------
-
1000
Caution:
The Flash Frequency High and Low Byte registers must be loaded with the correct value
to ensure proper operation of the device. Also, Flash programming and erasure is not
supported for system clock frequencies below 20 KHz or above 20 MHz.
Table 85. Flash Frequency High Byte Register (FFREQH)
BITS
FIELD
RESET
R/W
ADDR
0
R/W
0
R/W
0
R/W
0
R/W
FFAH
7
6
5
4
FFREQH
0
R/W
0
R/W
0
R/W
0
R/W
3
2
1
0
FFREQH—Flash Frequency High Byte
High byte of the 16-bit Flash Frequency value.
Table 86. Flash Frequency Low Byte Register (FFREQL)
BITS
FIELD
RESET
R/W
ADDR
7
6
5
4
FFREQL
0
R/W
FFBH
3
2
1
0
FFREQL—Flash Frequency Low Byte
Low byte of the 16-bit Flash Frequency value.
PS022815-0206
Flash Memory
ZILOG [ ZILOG, INC. ]
