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DSI SS7MD Programmer’s Manual Issue 3
4.9 Received Message Timestamping
Timestamping of received messages can be enabled for monitored links. This functionality provides a
timestamp of the time a message is received by a board. Individual boards maintain time by synchronising
with the host time.
The following table provides details of the expected timestamp accuracy between boards, in a multi board
system:
4.9.1 Host Configuration
The host must be configured to enable timestamping as follows:
1. Configure the LIU to operate in high-impedance mode using the <liu_type> parameter in the
LIU_CONFIG command, which has the following format:
LIU_CONFIG <brd_id> <liu_id> <liu_type> <line_code> <frame_format> <crc_mode>
For example, to configure E1 high-impedance mode, use the command:
LIU_CONFIG 0 0 6 1 1 1
2. Configure receive only monitoring links using the MONITOR_LINK command in the config.txt file, which
has the following format:
MONITOR_LINK <link_id> <board_id> <blink> <stream> <timeslot> <user_module>
<filter>
<flags> <phys_mask>
Timestamping is disabled by default. To enable timestamping on the monitored link, set bit 0 in the
<flags> field to 1. For example:
MONITOR_LINK 0 0 0 0 1 0xef 7 0x01 0xff
3. Configure the
s7_log
utility to display board and/or host timestamp information. See Section 8.1,
“s7_log” on page 162 for more information on the command line options for timestamping.
Note: To use the s7_log utility to display timestamps, monitoring messages must be redirected to the
s7_log
module ID in the MONITOR_LINK command.
4.9.2 Timestamp Output
Once timestamping is enabled, a timestamped API_MSG_RX_INDT message is issued by the board instead of
an API_MSG_RX_IND message. These messages are sent to the user module configured in the
MONITOR_LINK command.
The following are examples of messages without timestamping enabled:
S7L:I0000 M t8f01 i0000 f00 def s00 pffff0103
S7L:I0000 M t8f01 i0000 f00 def s00 pffff0103
The following are examples of messages with timestamping enabled:
S7L:I0000 M t8f0f i0000 f00 def s00 pffff01037caa8ec4e90f2abf
S7L:I0000 M t8f0f i0000 f00 def s00 pffff01037caa8ec4c3976bbf
If the decoding of the timestamps is enabled in the
s7_log
utility, the output look like the following:
S7L:2001-11-20 15:17:01.012 BRD:2001-11-20 15:17:01.011 I0000 M t7e20 i0000 f0d def s00 p00030001006000
Operating System Measured Accuracy
Linux 1 ms
Solaris 2 ms