FIFO DATA PACKETS
Symmetricom Inc
bc635VME/350VXI Time and Frequency Processor (Rev. E)
4-13
4.1.13 PACKET “O” REQUEST DATA FROM THE TFP
This packet is used to request data from the TFP which is not available via the register interfaces.
It was added as a “catch all” packet for universal data transfer. This packet has been created
with a very extensive format, and additional data will be made available as customer needs and
suggestions are addressed. The primary purpose of this packet is to allow the user to verify the
integrity of the programmed setup data.
Note:
The user is advised that repetitively issuing Packet “O” can cause excessive CPU
overhead and may disrupt time keeping.
Currently three different data packets may be requested using the “O” packet. The formats are as
follows:
Request Format
byte
1
SOH
byte
2
“O”
byte
3
“0” or “1” or “2” ...
byte
4
ETB
Response Format “0” Request RTC Time (See Packet “L”)
byte
1
SOH
byte
2
“o”
(lower case letter)
byte
3
“0” (zero)
byte
4
years tens
byte
5
years units
byte
6
months tens
byte
7 months
units
byte
8
day-of-month tens
byte
9
day-of-month units
byte
10
hours tens
byte
11
hours units
byte
12
minutes tens
byte
13
minutes units
byte
14
seconds tens
byte
15
seconds units
byte
16
ETB
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