Spectracom TPRO-cPCI, User Manual, Page: 31 / 46

TPRO-cPCI/TSAT-cPCI Spectracom Corporation
Synchronizable Timecode Generator User Manual 5-1
5
Commands and Responses
5.1 Introduction
To send a command:
1. Read the Status Register, do not proceed until:
Flag–Command Complete = 1.
2. Write the command to tbreg_cmd[3:0].
Important : Write to tbreg_cmd[3] last.
3. If a response is expected, read the Status Register until
Flag–Command Complete = 1, then read the response from tbreg_response[3:0].
Bits 15:00 of tbreg_cmd[3] specify the command operand. To maintain compatibility with future
products, write zeroes to fields listed as “(unused)”.
Writing to tbreg_cmd[3] causes the
Flag–Command Complete status bit to be de-asserted, and
signals the board to begin processing the command. This status bit is asserted after the board
finishes processing the command. Only one command can be processed at a time.
5.2 Set Time
0 x 0010
When not synced to GPS or incoming time code, the host computer can set the time. The time
then continues to increment from the set value (freewheel). However, if the GPS receiver
begins to track satellites, or if a time code input is applied, time jumps to the GPS or time code
time (unless synchronization has been disabled by the
Disable Sync command).
Set Time values are specified from days through seconds. The milliseconds and microseconds
are reset to zero when the command is processed. The time is formatted as Binary Coded
Decimal (BCD).
Bits tbreg_cmd[0] Bits tbreg_cmd[1]
31:28 (unused) 31:28 10s of seconds
27:24 100s of days 27:24 1s of seconds
23:20 10s of days 23:00 (unused)
19:16 1s of days
15:12 10s of hours
11:08 1s of hours
07:04 10s of minutes
03:00 1s of minutes
Bits tbreg_cmd[2] Bits tbreg_cmd[3]
31:16 (unused) 31:16 (unused)
15:12 1000s of Year 15:00 0x0010
11:08 100s of Year
07:04 10s of Year
03:00 1s of Year