Datasheet

Chapter 4 Memory
MC9S08LC60 Series Data Sheet: Technical Data, Rev. 4
Freescale Semiconductor 49
4.4.1 Features
Features of the FLASH memory include:
• FLASH Size
— MC9S08LC60 — 63,232 bytes (28,464 bytes in Flash B, 32,768 bytes in Flash A)
— MC9S08LC36 — 36,864 bytes (12,288 bytes in Flash B, 24,576 bytes in Flash A)
• 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 to minimize run I
DD
• FLASH read/program/erase over full operating voltage or temperature
4.4.2 Program and Erase Times
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
FCLK
) between 150 kHz and
200 kHz (see Section 4.6.1, “FLASH Clock Divider Register (FCDIV)). This register can be written only
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
FCLK
) is used by the command processor to time
program and erase pulses. An integer number of these timing pulses is used by the command processor to
complete a program or erase command.
Table 4-5 shows program and erase times. The bus clock frequency and FCDIV determine the frequency
of FCLK (f
FCLK
). The time for one cycle of FCLK is t
FCLK
= 1/f
FCLK
. The times are shown as a number
of cycles of FCLK and as an absolute time for the case where t
FCLK
=5μs. Program and erase times
shown include overhead for the command state machine and enabling and disabling of program and erase
voltages.
Table 4-5. Program and Erase Times
Parameter Cycles of FCLK Time if FCLK = 200 kHz
Byte program
945μs
Byte program (burst)
4
20 μs
1
1
Excluding start/end overhead
Page erase
4000 20 ms
Mass erase
20,000 100 ms