SM3 Datasheet, PDF (13/36 Pages) Connor-Winfield Corporation – ULTRA MINIATURE STRATUM 3 MODULE

Register Descriptions and Operation continued
When the device is in slave mode, it will lock to the M/S REF, independent of the values written to BITS 3 - 0 of the Op_mode
register. The operational mode and reference selection written to Bits 3 - 0 while in slave mode will, however, take effect when the
device is made the master.
When bit 1 of the Ctl_Mode register is reset (automatic reference and mode selection) and the device is in master mode, BITS 3 -
0 of the Op_Mode register become read-only.
Op_Mode, 0x05 (R/W)
Bit 7 ~ Bit 5
Reserved
Bit 4
Master or Slave Mode
1: Master
0: Slave
(Read Only)
Bit 3 ~ Bit 0
Free Run, Locked, or Hold Over:
0000: Free Run mode
0001: Locked on Ref1
0010: Locked on Ref2
0011: Locked on Ref3
0100: Locked on Ref4
0101 - 1000: Not Used
1001 - 1111: Hold Over
Max_Pullin_Range, 0x06 (R/W)
Bit 7 ~ Bit 0
Maximum pull-in range in 0.1 ppm unit
This register should be set according to the values specified by the standards (GR-1244) appropriate for the particular stratum of
operation. The power-up default value is 10 ppm. (= 4.6ppm aging + 4.6 ppm pullin + margin).
M/S_Activity, 0x07 (R)
Bit 7 ~ Bit 4
Reserved
Indicates signal presence and auto-detected frequency for the M/S REF input.
Bit 3 ~ Bit 0
Cross reference activity
0000: No signal
0001: 8kHz
0010:1.544 MHz
0011:2.048MHz
0100: 12.96MHz
0101: 19.44MHz
0110: 25.92MHz
0111: 38.88MHz
1000: 51.84MHz
1001: 77.76MHz
1010-1111: Reserved
Ref_Activity, 0x08 (R)
Bit 7
Bit 6
Bit 5
Bit 4
0: off
0: off
0: off
0: off
Each bit indicates the presence of a signal for that reference.
Bit 3
ref4 activity
1: on
0: off
Bit 2
ref3 activity
1: on
0: off
Bit 1
ref2 activity
1: on
0: off
Bit 0
ref1 activity
1: on
0: off
Data Sheet #: TM052 Page 13 of 36 Rev: 03 Date: 11/07/08
© Copyright 2008 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice