mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 67

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

4.4.3.2
The flash command controller is used to supervise the command write sequence to execute program, erase,
and erase verify algorithms.
Before starting a command write sequence, the FACCERR and FPVIOL flags in the FSTAT register must
be clear and the FCBEF flag must be set (see
A command write sequence consists of three steps which must be strictly adhered to with writes to the flash
module not permitted between the steps. However, flash register and array reads are allowed during a
command write sequence. The basic command write sequence is as follows:
Freescale Semiconductor
1. Write to a valid address in the flash array memory.
Command Write Sequence
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
Figure 4-9. Determination Procedure for PRDIV8 and FDIV Bits
set FDIV[5:0] = PRDCLK[kHz]/200-1
FCLK = (PRDCLK)/(1+FDIV[5:0])
PRDCLK = bus_clock/8
PRDIV8 = 0 (reset)
PRDCLK[kHz]/200
set PRDIV8 = 1
bus_clock
an integer?
≥12.8MHz?
bus_clock
START
0.3 MHz?
END
no
yes
yes
Section
yes
no
4.4.2.5).
no
PRDCLK = bus_clock
set FDIV[5:0] = INT(PRDCLK[kHz]/200)
ALL PROGRAM AND ERASE
COMMANDS IMPOSSIBLE
Memory
4-23