ACS8509 Semtech Corporation, ACS8509 Datasheet - Page 27

• Manufacturer Part Number: ACS8509
• Description: Synchronous Equipment Timing Source for Sonet or SDH Network Elements
• Manufacturer: Semtech Corporation

Table 14 Register Description (cont...)
Revision 2.00/January 2006 © Semtech Corp.
ADVANCED COMMUNICATIONS
26
27
2A
2C
Addr.
(Hex)
cnfg_ref_source_
frequency
Register Name
This register is used to set up each of the 4 input reference sources.
Bits (7:6) of each byte defines the operation undertaken on the input frequency, in
accordance with the following key:
00
01
10
11
Bits (5:4) define which leaky bucket group (0-3) is used, as defined in registers 50 to
5F. (default 00).
Bits (3:0) defines the frequency of the reference source in accordance with the
following:
0000 8 kHz,
0001 1.544 MHz (SONET)/2.048 MHz (SDH) (as defined by register 34, bit 2)
0010 6.48 MHz (default <SEC3> when MSTSLVB = 1),
0011 19.44 MHz (default <SEC3> when MSTSLVB=0, and <SEC1> <SEC2>),
0100 25.92 MHz,
0101 38.88 MHz,
0110 51.84 MHz,
0111 77.76 MHz,
1000 155.52 MHz,
1001 2 kHz,
1010 4 kHz.
Frequency of reference source <SEC1>.
Frequency of reference source <SEC2>.
Frequency of reference source <SEC3>.
Frequency of reference source <SEC4>.
The input frequency is fed directly into the DPLL. (default).
The input frequency is internally divided down to 8 kHz, before being fed into
the DPLL. (For high jitter tolerance).
Unsupported configuration - do not use.
Uses the division coefficient stored in registers 46 and 47 (cnfg_freq_divn) to
divide the input by this value prior to being fed into the DPLL. The frequency
monitors must be disabled. The divided down frequency should equal 8 kHz.
The frequency (3:0) should be set to the nearest spot frequency just below the
actual input frequency. The DivN feature works for input frequencies between
1.544 MHz and 100 MHz.
(default SEC4),
FINAL
Page 27
Description
ACS8509 SETS
Default Value (Bin)
DATASHEET
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(MSTSLVB=0)
(MSTSLVB=1)
00000011
00000011
00000010
00000011
00000001