4:6 PT PLL Tuning Note: The tune bits adjust parameters that
000 Choice
1;
TUNE[5:0] = 010001
control PLL jitter. The recommended values
001
Choice 2; TUNE[5:0] = 010010
minimize jitter for the PLL implemented in
010 Choice
3;
TUNE[5:0] = 010011
the PPC405GP. These bits are shown for
011
Choice
4;
TUNE[5:0] = 010100
information only, and do not require
100 Choice
5;
TUNE[5:0] = 010101
modification except
in
special clocking
101
Choice
6;
TUNE[5:0] = 010110
circumstances, such as spread spectrum
110 Choice
7;
TUNE[5:0] = 010111
clocking. For details on the use of spread
111
Choice
8;
TUNE[5:0] = 100100
spectrum clock generators (SSCGs) with
the
PPC405GP, visit the technical
documents area of the IBM PowerPC web
site.
7:8
PDC PLB Divider from CPU
00
Divide By 1
01
Divide By 2
10 Divide By 3
11
Divideยท By 4
9:10 ODP OPB Divider from PLB
00
Divide By 1
01
Divide By 2
10 Divide By 3
11
Divide By 4
11
:12 PDP PCI Divider from PLB
00
Divide By 1
01
Divide By 2
10 Divide By 3
11
Divide By 4
13:14
EBDP External Bus Divider from PLB
00
Divide By 2
01
Divide By 3
10 Divide By 4
11
Divide By 5
15:16 RW
ROM Width
00 8-bit ROM
01
16-bit ROM
10
32-bit ROM
11
Reserved
17 RL
ROM Location
o 405GP Peripheral Attach
1
405GP PCI Attach
18
..
Reseยทrved
19
PAME
PCI Asynchronous Mode Enable
o Synchronous PCI Mode
1 Asynchronous Mode
20 Reserved
...
21
PAE
PCI Arbiter Enable
o Internal Arbiter Disabled
1 Internal Arbiter Enabled
22:31
I
Reserved
9-2
PPC405GP User's Manual Preliminary