mc9s08qg8 Freescale Semiconductor, Inc, mc9s08qg8 Datasheet - Page 44

• Manufacturer Part Number: mc9s08qg8
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 4 Memory Map and Register Definition
4.5.1
Features of the FLASH memory include:
4.5.2
Before any program or erase command can be accepted, the FLASH clock divider register (FCDIV) must
be written to set the internal clock for the FLASH module to a frequency (f
200 kHz (see
once, so normally this write is done during reset initialization. FCDIV cannot be written if the access error
flag, FACCERR in FSTAT, is set. The user must ensure that FACCERR is not set before writing to the
FCDIV register. One period of the resulting clock (1/f
program and erase pulses. An integer number of these timing pulses are used by the command processor
to complete a program or erase command.
Table 4-5
of FCLK (f
of cycles of FCLK and as an absolute time for the case where t
shown include overhead for the command state machine and enabling and disabling of program and erase
voltages.
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FLASH size
— MC9S08QG8: 8,192 bytes (16 pages of 512 bytes each)
— MC9S08QG4: 4,096 bytes (8 pages of 512 bytes each)
Single power supply program and erase
Command interface for fast program and erase operation
Up to 100,000 program/erase cycles at typical voltage and temperature
Flexible block protection
Security feature for FLASH and RAM
Auto power-down for low-frequency read accesses
shows program and erase times. The bus clock frequency and FCDIV determine the frequency
Program and Erase Times
FCLK
Features
Section 4.7.1, “FLASH Clock Divider Register
Byte program
Byte program (burst)
Page erase
Mass erase
1
). The time for one cycle of FCLK is t
Excluding start/end overhead
Parameter
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 1.01
Table 4-5. Program and Erase Times
Cycles of FCLK
20,000
4000
9
4
FCLK
FCLK
) is used by the command processor to time
= 1/f
(FCDIV)”). This register can be written only
FCLK
FCLK
Time if FCLK = 200 kHz
= 5 µs. Program and erase times
. The times are shown as a number
FCLK
100 ms
20 µs
20 ms
45 µs
) between 150 kHz and
1
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