Simplex G-Link Test Destination
Card (TDC) Data Sheet
This Data Sheet describes a test data checker card which is using the HP
G-Link as physical medium. This receiver is checking the data sent by
Data Source (TSC) card. It is not recommended to use this card with
any other G-Link transmitter. Use the simplex
G-Link-S-LINK LDC instead.
This card is using the same hardware as the simplex
G-Link-S-LINK LDC, it differs from it in the FPGA configuration.
Data Transfer Rate
The expected parallel data rate is 40 Mhz. This corresponds to 960 Mbaud
serial data rate since the G-Link in 20 bit mode sends 24 bit data with
each 20 bit data word. Flow control is not implemented.
The card expects to receive data in packets which consist of a start of
packet control word, 224 data words and an end of packet control word.
Fill Frames are transmitted between the packets. Test data is sent on the
16 LSB of the data words. Bits 19-16 contain the odd parity of each four
bits of the 16 LSB and used for error detection. E.g. bit 20 is the odd
parity of bits 15-12.
Four different data patterns can be selected with the URL1, URL0 return
line inputs (see Table 1).
The 16 MSB of the S-LINK data output are used for error checking
and diagnostic purposes. Table 2 shows the allocation of LD[31..0] bits.
The "#" symbol means an active low signal.
Table 1: Output Selection
||Link Up Led
||P1, P0 setting on TSC
|CAV# (Control Word)
||DAV# (Data Word)
||ERR (G-Link error)
||FLAG (G-Link Flag)
Table 2: Output Data bits
||Packet length error
||LD[23..21] is not zero
4 jumpers can be used to select different operation modes. Operation modes
in bold italics MUST be selected on this card.
Table 3: Operation Modes
||Flag bit mode: Flag bit can be used as an extra dataword.
||Flag bit is is internally alternated by G-Link for enhanced error
||20 bit G-Link mode
||16 bit G-Link mode
||Link Synchronisation with on-board reference oscillator
||Link Synchronisation with sync. pulses (Fill Frames)
||Write only erroneous words
||Write all received words
The following setting must be used when this card is used with the Test
Data Source card:
TP3: On (If this jumper is removed, the TSC must be reset to send sufficient
fill frames for the receiver to synchronise.)
TP4: It is up to the user to decide whether it is more convenient to
reveive all the data words and trigger on the words in error only (e.g.
with a logic analyzer) or receive only the erroneous word (e.g. with an
S-LINK destination system).
Power Led (green): It turns on when the card is powered with 5 V.
Link Up Led (green): This led turns on after the PLL of the G-Link
deserialiser is synchronised.
Data Error led (red): This Led turns on when data comparison, parity
or frame length error is detected. It turns off on the high to low transition
of URESET# input.
Selftest Led (red): This led is illuminated when the UTEST# input
is logic low.
Last Updated: 28.06.1999 by Zoltán