AN2400 Freescale Semiconductor / Motorola, AN2400 Datasheet - Page 7

• Manufacturer Part Number: AN2400
• Description: HCS12 NVM Guidelines
• Manufacturer: Freescale Semiconductor / Motorola

MOTOROLA
TRY TO DECREASE Tbus
Figure 7. PRDIV8 and FDIV bits Determination Procedure
Freescale Semiconductor, Inc.
FDIV[5:0]=PRDCLK[MHz]*(5+Tbus[µs])-1
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PROGRAM/ERASE IMPOSSIBLE
yes
FCLK=(PRDCLK)/(1+FDIV[5:0])
PRDCLK[MHz]*(5+Tbus[µs])
1/FCLK[MHz] + Tbus[µs] ≥ 5
PRDCLK=oscillator clock/8
PRDIV8=0 (reset)
FCLK ≥ 0.15MHz
oscillator clock
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FDIV[5:0] ≥ 4?
Tbus ≤ 1µs?
HCS12 NVM Guidelines
PRDIV8=1
an integer?
START
12.8MHz?
AND
?
yes
yes
yes
no
no
no
no
PRDCLK=oscillator clock
no
yes
FDIV[5:0]=INT(PRDCLK[MHz]*(5+Tbus[µs]))
PROGRAM/ERASE IMPOSSIBLE
END
Split-Gate Flash Memory
AN2400/D
7