Agere Systems Inc.
63
Data Sheet
May 2001
and Packet Payload Engine
Ambassador T8110 PCI-Based H.100/H.110 Switch
7 Clock Architecture
(continued)
7.1 Clock Input Control Registers
The following registers control the T8110 main clocking paths and NETREF paths.
7.1.1 Main Input Selector
Register
The main input selector register controls clock and frame input selection.
* C2 is allowed as the bit clock input.
Choices include the following:
Oscillator/crystal clock = XTAL1_IN (16.384 MHz), no frame
NETREF1 clock = CT_NETREF1 (8 kHz, 1.544 MHz, or 2.048 MHz), no frame
NETREF2 clock = CT_NETREF2 (8 kHz, 1.544 MHz, or 2.048 MHz), no frame
LREF individual clock = one of LREF[0:7]*, no frame
LREF paired
clock = one of LREF[0:3], frame = one of LREF[4:7]*
H-bus A-clocks
clock = CT_C8_A (8.192 MHz), frame = /CT_FRAME_A (8 kHz)
*
Selection of which LREF is controlled at register 0x00208. Selection of LREF polarity is controlled at register 0x0020C.
Table 43. Clock Input Control Register Map
DWORD Address
(20 bits)
Register
Byte 3
Byte 2
Byte 1
Byte 0
0x00200
0x00204
0x00208
0x0020C
0x00210
0x00214
APLL1 rate
APLL2 rate
DPLL1 rate
DPLL2 rate
Reserved
Reserved
APLL1 input selector
Reserved
DPLL1 input selector
DPLL2 input selector
NETREF1 LREF select
NETREF2 LREF select
Main divider
Resource divider
Reserved
Reserved
NETREF1 divider
NETREF2 divider
Main input selector
Main inversion select
LREF input select
LREF inversion select
NETREF1 input selector
NETREF2 input selector
Table 44. Main Input Selector Register
Byte Address
Name
Bit(s)
Mnemonic
Value
Function
0x00200
Main Input Selector
7:0
CKMSR
0000 0000
0001 0001
0001 0010
0010 0001
0010 0010
0100 0001
0100 0010
0100 0100
0100 1000
1000 0000
1000 0001
1000 0010
1000 0100
1000 1000
Select oscillator/crystal (default).
Select NETREF1.
Select NETREF2.
Select LREF[0:7] individually.
Select LREF[0:3, 4:7] paired.
Select H-bus A-clocks.
Select H-bus B-clocks.
Select MC1 R-clocks.
Select MC1 L-clocks.
Select MVIP clocks (C2 bit clock)*.
Select MVIP clocks (/C4 bit clock).
Select H-MVIP
clocks (/C16± bit clock).
Select SC-bus clocks 2 MHz.
Select SC-bus clocks 4/8 MHz.