Simplex G-Link Receiver Card Data Sheet


This Data Sheet describes a Simplex Destination card which uses the HP G-Link HDMP-1024 receiver and optical or electrical physical media. This card is equipped with an S-LINK interface and data can be read with any S-Link read-out system.

Data Transfer Rate

The maximum clock rate (LCLK) is 40 Mhz. Minimum frequency of LCLK is 17.5 Mhz in 16 bit G-Link mode and 29.2 Mhz in 20 bit G-Link mode. 32 words at 40 Mwords/sec (40Mhz LCLK) is above the specified data rate for G-Link so not guaranteed but is inside the typical maximum data rate. Maximum guaranteed data rate is 37.5 Mword/sec in 32 bit mode.

Since it is a simplex link, flow control is not available. The Uxoff# input is reserved.

Operation modes

The "TP2" 20 bit mode selector jumper must be on the card when the transmitter is in 20 bit mode.  4 jumpers can be used to select different operation modes. Flag mode and 20 bit G-Link mode selection must be the same on both source and destination cards.
Jumpers TP[1..4] On Off
TP1 Flag bit mode: Flag bit can be used as an extra dataword. Flag bit is is internally alternated by G-Link for enhanced error detection. 
TP2 20 bit G-Link mode 16 bit G-Link mode
TP3 Link Synchronisation with on-board reference oscillator Link Synchronisation with sync. pulses (Fill Frames)
TP4 Reserved
Table 2: Operation Modes

Optical Power and Board Temperature Measurement

It is possible to measure received optical power and the temperature of the circuit board next to the G-Link deserialiser (HDMP-1024). On a high-low transition of the UTDO# (S-LINK) input a control word is sent whith optical power and temperature measurement results. Optical power in dBm is -0.1 times the decimal value on bits 23-16. E.g. the binary "01000001" value means -6.5dBm. Temperature can be read on bits 15-6 with 0.25 degrees accuracy E.g. "0011000110" means 49.5 °C.   UTDO must be pulled high to receive G-Link data.
LD [31..24] LD[23..16] LD[15..8] LD[7..6] LD5 LD[4..0]
Reserved -10*Power [dbm] Temperature [°C] Temperature [1/4°C]  Alarm: Temp.>50°C "01100"

 Data output

The 16 MSB of the S-LINK data output are used for error checking and diagnostic purposes. Table 4 shows the allocation of LD[31..0] bits. The "#" symbol means an active low signal.
LD31 LD30 LD29 LD28 LD[27..24]
CAV# (Control Word) DAV# (Data Word) ERR (G-Link error) FLAG (G-Link Flag) Free running counter
LD23 LD[22..20] LD[19..16] LD[15..0]
LINKRDY# Reserved Rx Data (Parity) Rx Data
 Table 3: Output Data bits
Error Detection

Word by word error reporting is possible using the "Error" signal of G-Link.

Led Indicators

 Last Updated on 30.06.1999 by Zoltán Meggyesi