Microsemi SA.45s, User Manual

SA.45s Chip-Scale Atomic Clock

SA.45s CSAC User Guide Revision D

21

1.  

2.  

3.  

The maximum length of a telemetry string is 135 characters.
Note: The single-characters   and   are shortcuts for 

 and 

, respectively.

6

^

!6[CRLF]

!^[CRLF]

The following table lists the telemetry parameters and their associated header identifiers.

Table 6 • Telemetry Parameters (Firmware Version 1.09)

Identifier

Description

Notes

String Length

Status

Unit status

See Note 1 and 

Table 7 (see 

page 22)

Up to 2 decimal digits (2 characters)

Alarm

Pending unit 
alarms

See Note 2 and 

Table 8 (see 

page 22)

“0x” + 4 hexadecimal digits (6 
characters max)

SN

Unit serial number

See Note 3

11 characters

Mode

Mode of 
operation

See 

Table 9 (see page 24)

“0x” + 4 hexadecimal digits (6 
characters max)

Contrast

Indication of 
signal level

Typically >2000 when locked, 
and ≈ 0 when unlocked

32 bits unsigned (10 characters max)

LaserI

Laser current (mA)

Typically 0.6 mA–1.3 mA

16 bits un “.” + 2 digits 
precision (8 characters max)

TCXO

Tuning voltage (V)

0 VDC–2.5 VDC tuning range 
≈ ±10 × 10

6

16 bits un “.” + 3 digits 
precision (9 characters max)

HeatP

Physics package 
heater power 
(mW)

Typical 6 mW–20 mW under 
normal operating conditions 
and 25 °C ambient

16 bits un “.” + 2 digits 
precision (8 characters max)

Sig

DC signal level (V)

Typical 0.8 V–1.7 V under 
normal operating conditions

16 bits un “.” + 3 digits 
precision (9 characters max)

Temp

Unit temperature 
(°C)

Absolute accuracy is ±2 °C

16 bits un “.” + 2 digits 
precision (8 characters max)

Steer

Frequency adjust

In ×10  resolution

–12

32 bits signed (11 characters max)

ATune

Analog tuning 
voltage input

--- when analog tuning is 
disabled, 0 V–2.5 V when 
enabled

16 bits un “.” + 3 digits 
precision (9 characters max)

Phase

Difference 
between CSAC 
and external 1PPS 
(ns)

Only present if discipline or 
phase-measure mode 
enabled, otherwise 

or 

--- 

NEEDREFPPS

16 bits signed (6 characters max)

DiscOK

Discipline status 
(0-2)

0 = acquiring, 1 = locked, 2 = 
holdover when disciplining 
enabled, otherwise ---

“0", “1", “2" or “---“ (3 characters 
max)

TOD

Time (seconds)

Starts at 0 upon power-up 
unless set by command

32 bits unsigned (10 characters max)

LTime

Time since lock 
(seconds)

Starts at 0 upon lock

31 bits unsigned (10 characters max)

FWver

Firmware version

Two digit number M.m 
where M is major revision 
and m is minor revision

“1.09” (4 characters, may be longer 
in future firmware)

Notes:

Status reflects the steps of the clock initialization process. It starts at 8 on boot and decreases to 0 as 
acquisition proceeds. When Status ≠ 0, BITE = 1. When Status = 0, BITE = 0.
Alarms indicate detection of anomalous operating conditions while locked. Alarm is the logical OR of 
all pending alarms, as shown in the following table. An alarm will not persist if the condition is fixed 
or if the unit is reset.
CSAC serial numbers are of the form YYMMCSXXXXX where YYMM is the year and month of