Simplex G-Link S-LINK Link Destination
Card Data Sheet
This Data Sheet describes a Simplex S-Link LDC which is using
the HP G-Link HDMP-1024 receiver and optical or electrical physical media.
Data Transfer Rate
The maximum clock rate (LCLK) is 40 Mhz. Minimum frequency of LCLK is
Since it is a simplex link, flow control is not available. The UXOFF#
input is ignored. LFF# on the LSC indicates that the input FIFO is full.
LFF# will always be inactive (logic high) in 16 bit mode.
Data Width Options
This S-Link is of switchable width and can be operated in the following
The user has to make sure that the data width (UDW[1..0] inputs) have the
same setting on both LSC and LDC.
Table 1: S-LINK Datawidth options
LCLK (UCLK) Mhz
|Serial Baud Rate at 40Mhz LCLK
|00 (32 bit)
||Coding + Parity
|01 (16 bit)
||Coding + Flag + Parity
Link synchronisation mode can be selected with a jumper.
TP3 is removed (default): Link Synchronisation with synchronous
pulses (Fill Frames). The LSC must send Fill Frames for ~1ms to synchronise
TP3 is inserted: Link Synchronisation with on-board reference
oscillator. UCLK must be 40 Mhz. LSC does not need to send fill frames.
The link will work without using URESET# signal on the LSC.
Mapping into G-Link
This information is necessary for the Link Source Card implementation.
20 bit single frame G-Link mode is used, odd parity of each four bits
of LD[15..0] are sent on the LD[19..16] lines respectively for error detection
(E.g. LD16 is the odd parity of LD[3...0]).
When 32bit S-LINK data width is selected (by the UDW[1..0] lines),
32 bit S-Link words are sent in two 20 bit G-Link word. The G-Link FLAG
indicates which half of the S-Link word has been received. The logic high
value of FLAG means that the received word is sent from UD[31..16] of the
S-LINK LSC so the LDC will write it to LD[31..16]. In this mode the LSC
will pull the Link Full Flag (LFF#) down whenever its input FIFO is full,
which may mean that that LFF# goes low on every other dataword.
S-LINK control words are mapped into G-Link control words. Bits 19-18
are reserved for G-Link, bit 17 differentiate a test control word (0) from
a normal control word (1) and bit 16 is the odd parity of bits 15-0. The
user receives only the data part of the control word on LD[15..4] according
to the S-Link specification..
Table 2: Mapping S-Link words into G-Link
|0 0 (32 bit)
||20 bit Single Frame + Flag
|0 1 (16 bit)
||20 bit Single Frame
Table 3: Control word transmission
|Reserved for G-Link
||0 => Test Control Word
|| Odd parity of LD[15..0]
||Reserved for S-LINK
Selftest mode is implemented in all operation modes according to the S-LINK
specification. Test Data is Checked and the Data Error Led is illuminated
and the LDERR# signal is pulled down on test data comparison error.
As this is a simplex S-Link, the Return Lines are not used.
Word by word error reporting is implemented using the "Error" signal
of G-Link and parity checking. Four parity bits are transmitted with the
datawords, parity is checked in each half byte (4 bits) on the transmitted
word. One parity bit is transmitted with each control word.
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 G-Link Error or Parity
error is detected or on test data comparison error. It turns off on the
high to low transition of URESET# input.
Selftest Led (red): This led is illuminated when the Link Source
Card is sending Test Data.
Last Updated on 30.06.1999 by Zoltán