The diagnostic utility of this mode resides in the fact that the operator can immediately determine
if the host program is communicating properly with the TFP by simply observing the display. To
borrow from the classic K&R. To make
12:34:56
appear "you have to be able to create the program
text, compile it, run it, and find out where your output went. With these mechanical details
mastered, everything else is comparatively easy."
4.1.2 PACKET 'B' SET MAJOR TIME
In mode 1 and mode 2 the only way to set major time is using this packet. I t is not likely that this
packet would be used in any other mode since all other modes derive major time from the timing
reference signal. The packet format is as follows:
byte 1 S O H
byte 2 ' B '
byte 3 d a y s hundreds
byte 4 d a y s tens
byte 5 d a y s units (Jan 1 is defined as day 001)
byte 6 h o u r s tens
byte 7 h o u r s units
byte 8 m i n u t e s tens
byte 9 m i n u t e s units
byte 1 0 s e c o n d s tens
byte 1 1 s e c o n d s units
byte 1 2 E T B
Note: All data fields must be ASCII.
The time loaded by packet 'B' will not be used until the 1 second epoch following the load. The TFP
increments the time before loading it to output buffer registers. The time is incremented at
approximately 900 milliseconds into the current frame, and the buffer registers are loaded 950
milliseconds into the current frame. The buffer registers are transferred to a set of holding registers
synchronously with the 1PPS output. The time loaded by packet 'B' should be input well in advance
of the 918 millisecond point in the frame, and should reference the current frame.
4.1.3 PACKET 'C' COMMAND INPUT
This packet has a single data byte and is used to direct the TPF to take the specific actions below.
'1' n o t used ( w a r m s t a r t on early software versions)
'2' s o f t w a r e reset v e c t o r s TFP CPU to power on reset point
'3' j a m s y n c h f o r c e TFP minor time to zero on the next 1PPS input
'4' n o t used ( j a m s y n c h lockout on early software versions)
'5' b u f to RTC l o a d current time to the Real Time Clock IC
'6' v a r i a b l e s d u m p s battery backed RAM to
FIFO (factory use only)
Datum Inc., Bancomm Div.
bc635VME/bc350VXI Manual
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