S912XEG128J2MAA Datasheet, PDF (1228/1324 Pages) Freescale Semiconductor, Inc – Microcontrollers

Appendix A Electrical Characteristics
A.3.1.19 Enable EEE (FCMD=0x13)
The maximum time to enable EPROM emulation is given by
t = _{⎝⎛⎝⎛((}1100 ⋅ BWN + (176 ⋅ (1 + BWN) + (BWN + N_SEC) ⋅ 32364))) ⋅ _f--N----_V---1_M----_O----_P-_⎠⎞ +
⎛
⎝
(
3050
⋅
(
1
+
BWN
)
+
(
N_SE
C
+
B
W
N
)
⋅
290500 )
⋅
-f-_N----_V---_M-1---_B---_U----_S- _⎠⎞
⎞
⎠
where N_SEC is the number of sectors of constant data. A constant sector is one in which all 63 records
contain the latest active data and would need to be copied. The maximum possible is 33 (2048 EEE RAM
words /63 =32.5) although this is a highly unlikely scenario. The impact of a worst case brownout recovery
scenario is denoted by BWN = 2 for non brownout situations BWN =0.
1228
MC9S12XE-Family Reference Manual Rev. 1.25
Freescale Semiconductor