IBM POWERPC 750GL User Manual
Page 70
User’s Manual
IBM PowerPC 750GX and 750GL RISC Microprocessor
Programming Model
Page 70 of 377
gx_02.fm.(1.2)
March 27, 2006
2.1.2.3 Hardware-Implementation-Dependent Register 1 (HID1)
The Hardware-Implementation-Dependent Register 1 (HID1) reflects the state of the PLL_CFG[0:4] signals.
HID1 can be accessed with mtspr and mfspr using SPR 1009.
PCE
PRE
PS
TA
T1
EC
L
K
Reserved
Res
e
rv
ed
PI
0
PS
PC0
PR0
Res
e
rv
ed
PC1
PR1
Res
e
rv
ed
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Bits
Field Name
Description
0:4
PCE
PLL external configuration bits (read-only).
5:6
PRE
PLL external range bits (read-only).
7
PSTAT1
PLL status. Specifies the PLL clocking the processor:
0
PLL0 is the processor clock source
1
PLL1 is the processor clock source.
8
ECLK
Set to 1 to enable the CLKOUT pin.
9:11
Reserved
Select the internal clock to be output on the CLKOUT pin with the following decode:
000
Factory use only
001
PLL0 core clock (freq/2)
010
Factory use only
011
PLL1 core clock (freq/2)
100
Factory use only
101
Core clock (freq/2)
Other
Reserved
Note: These clock configuration bits reflect the state of the PLL_CFG[0:4] pins. Clock
options should only be used for design debug and characterization.
12:13
Reserved
Reserved.
14
PI0
PLL 0 internal configuration select.
0
Select external configuration and range bits to control PLL 0.
1
Select internal fields in HID1 to control PLL0.
15
PS
PLL select.
0
Select PLL 0 as the source for the processor clock.
1
Select PLL 1 as the source for the processor clock.
16:20
PC0
PLL 0 configuration bits.
21:22
PR0
PLL 0 range select bits.
23
Reserved
Reserved.
24:28
PC1
PLL 1 configuration bits.
29:30
PR1
PLL 1 range bits.
31
Reserved
Reserved.