mc9s12e256 Freescale Semiconductor, Inc, mc9s12e256 Datasheet - Page 103

• Manufacturer Part Number: mc9s12e256
• Description: Hcs12 Microcontrollers 16-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Freescale Semiconductor
TRY TO DECREASE Tbus
Figure 2-22. Determination Procedure for PRDIV8 and FDIV Bits
FDIV[5:0]=PRDCLK[MHz]*(5+Tbus[ s])-1
YES
ALL COMMANDS IMPOSSIBLE
FCLK=(PRDCLK)/(1+FDIV[5:0])
PRDCLK[MHz]*(5+Tbus[ s])
1/FCLK[MHz] + Tbus[ s] > 5
PRDCLK=oscillator_clock/8
MC9S12E256 Data Sheet, Rev. 1.08
PRDIV8=0 (reset)
FCLK > 0.15 MHz
FDIV[5:0] > 4?
OSCILLATOR
Tbus < 1 s?
> 12.8 MHZ?
an integer?
PRDIV8=1
START
CLOCK
AND
?
YES
YES
YES
NO
NO
NO
NO
PRDCLK=oscillator_clock
YES
NO
FDIV[5:0]=INT(PRDCLK[MHz]*(5+Tbus[ s]))
ALL COMMANDS IMPOSSIBLE
Chapter 2 256 Kbyte Flash Module (FTS256K2V1)
END
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