Z8F0830HH020SG Datasheet, PDF (141/257 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore!^® F0830 Series
Product Specification
123
Flash Frequency High and Low Byte Registers
The Flash Frequency High and Low Byte registers, shown in Tables 76 and 77, 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
Caution: Flash programming and erasure is not supported for system clock frequencies below
10 kHz or above 20 MHz. The Flash Frequency High and Low Byte registers must be
loaded with the correct value to ensure proper operation of the device.
Table 76. Flash Frequency High Byte Register (FFREQH)
Bit
7
6
5
4
3
2
1
0
Field
FFREQH
RESET
0
0
0
0
0
0
0
0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Address
FFAH
Bit
Description
[7:0]
Flash Frequency High Byte
FFREQH High byte of the 16-bit Flash frequency value.
Table 77. Flash Frequency Low Byte Register (FFREQL)
Bit
7
6
5
4
3
2
1
0
Field
FFREQL
RESET
0
R/W
R/W
Address
FFBH
Bit
Description
[7:0]
Flash Frequency High Byte
FFREQL Low byte of the 16-bit Flash frequency value.
PS025113-1212
Flash Control Register Definitions