MC9S12XD256MAL Datasheet, PDF (1051/1348 Pages) Freescale Semiconductor, Inc – Freescale’s Scalable Controller Area Network

Chapter 25 2 Kbyte EEPROM Module (S12XEETX2KV1)
START
Tbus < 1µs?
no
ALL COMMANDS IMPOSSIBLE
yes
PRDIV8 = 0 (reset)
oscillator_clock
no
>12.8 MHz?
yes
PRDIV8 = 1
PRDCLK = oscillator_clock/8
PRDCLK
=
oscillator_clock
PRDCLK[MHz]*(5+Tbus[µs]) ^no
an integer?
yes
EDIV[5:0]=INT(PRDCLK[MHz]*(5+Tbus[µs]))
EDIV[5:0]=PRDCLK[MHz]*(5+Tbus[µs])–1
TRY TO DECREASE Tbus EECLK = (PRDCLK)/(1+EDIV[5:0])
1/EECLK[MHz] + Tbus[ms] > 5 ^yes
AND
EECLK > 0.15 MHz
?
no
END
yes _{EDIV[5:0] > 4?}
no
ALL COMMANDS IMPOSSIBLE
Figure 25-17. Determination Procedure for PRDIV8 and EDIV Bits
Freescale Semiconductor
MC9S12XDP512 Data Sheet, Rev. 2.21
1053