MPC555
/
MPC556
CLOCKS AND POWER CONTROL
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
8-28
Flash programming requirements are the same as normal system power, ex-
cept VPP = 5.0 ± 0.25 V
4. Do not hold the 3-V supplies at ground while VDDH/VDDA is ramping to 5 V.
5. If 5 V is applied before the 3-V supply, all 5-V outputs will be in indeterminate
states until the 3-V supply reaches a level that allows reset to be distributed
throughout the device
8.12 Clocks Unit Programming Model
8.12.1 System Clock Control Register (SCCR)
The SPLL has a 32-bit control register, SCCR, which is powered by keep-alive power.
NOTES:
1. The hard reset value is a reset configuration word value, extracted from the indicated internal data bus lines.
7.5.2 Hard Reset Configuration Word
.
U = Unaffected by reset
2. RTDIV will be 0 if MODCK[1:3] = 0b000
3. EQ2 = MODCK1
4. EQ3 = (MODCK1 & MODCK2 & MODCK3) | (MODCK1 & MODCK2 & MODCK3) | (MODCK1 & MODCK2 &
MODCK3). See
5. On mask sets prior to K62N, ENGDIV defaults to 0b000001.
SCCR — System Clock Control Register
0x2F C280
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
DBCT
COM
DCSLR
MFPDL
LPML
TBS
RTDIV
2
STBUC
RE-
SERVED
PRQEN RTSEL
BUCS
EBDF
LME
POWER-ON RESET:
1
0
ID2
1
0
0
0
0
1
2
0
0
1
EQ2
3
ID[13:14]
1
EQ3
4
HARD RESET:
U
0
ID2
1
U
0
0
U
U
U
0
1
U
U
ID[13:14]
1
U
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
LSB
31
EECLK
ENGDIV
5
—
DFNL
—
DFNH
POWER-ON RESET:
0
0
1
1
1
1
1
1
0
0
0
0
0
0
0
0
HARD RESET:
U
U
U
U
U
U
U
U
0
0
0
0
0
0
0
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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