SA.45s Chip-Scale Atomic Clock
SA.45s CSAC User Guide Revision D
24
3.4.3.3
Set/Clear Operating Modes (M)
Operating modes of the CSAC are enabled/disabled by individual bits in the mode register. The
!M
command provides access to set/clear each of the bits independently. The mode register is non-volatile;
settings persist across power cycles.
The unit responds by reporting the current value of the mode register in hexadecimal. Each bit in the
mode register is associated with enabling/disabling a particular operating mode. The bit assignments are
shown in the following table.
Table 9 • Operating Modes of CSAC
Enable Bit Assignment
Enable Argument to !M_
Definition
Disable Argument to !M_
0x0001
A
Analog tuning
a
0x0002
Reserved
0x0004
M
1PPS phase
measurement (only
available on firmware
versions 1.08 and later)
m
0x0008
S
1PPS auto-sync
s
0x0010
D
Discipline
d
0x0020
U
Ultra-Low Power mode
u
0x0040
C
Require checksum on
!
command
c
0x0080
Reserved
?
Report current settings
Example (Enable and then Disable analog tuning):
Command:
!MA[CRLF]
Unit response:
0x0001[CRLF]
Command:
!Ma[CRLF]
Unit response:
0x0000[CRLF]
The current value of the mode register is returned in the standard telemetry query (see
) or may be queried independently with the
command.
!M?
Example (query mode register):
Command:
!M?[CRLF]
Response:
0x0001[CRLF]
Note: That the single-character is a shortcut for
.
M
!M?[CRLF]
Autosync mode, Discipline mode, and Phase Measurement mode (if mode available in the firmware
version) are mutually exclusive. Setting a 1PPS-related option automatically disables the other 1PPS-
related options.
