Lattice Semiconductor ispXPGA Family Data Sheet
18
High Speed Serial Interface Block (sysHSI Block)
1
The High Speed Serial Interface (sysHSI) allows high speed serial data transfer over a pair of LVDS I/O. The
ispXPGA devices have multiple sysHSI blocks.
Each sysHSI block has two SERDES blocks which contain two main sub-blocks, Transmitter (with a serializer) and
Receiver (with a deserializer) including Clock/Data Recovery Circuit (CDR). Each SERDES can be used as a full
duplex channel. The two SERDES in sysHSI blocks share a common clock and must operate at the same nominal
frequency. Figure 20 shows the sysHSI block.
Device features support two data coding modes: 10B/12B and 8B/10B (for use with other encoding schemes, see
Lattice’s sysHSI technical notes). The encoding and decoding of the 10B/12B standard are performed within the
sysHSI block. For the 8B/10B standard, the symbol boundaries are aligned internally but the encoding and decod-
ing are performed outside the sysHSI block.
Each SERDES block receives a single high speed serial data input stream (with embedded clock) from an input,
and provide a low speed 10-bit wide data stream and a recovered clock to the device. For transmitting, SERDES
converts a 10-bit wide low-speed data stream to a single high-speed data stream with embedded clock for output.
Additionally, multiple sysHSI blocks can be grouped together to form a source synchronous interface of 1-10 chan-
nels.
For more information on the SERDES/CDR, refer to Lattice technical note number TN1020, sysHSI Usage Guide-
lines.
Figure 20. sysHSI Block Diagram
1. “E-Series” does not support sysHSI.
Shared Source
Synchronous Pins Drive
Multiple sysHSI blocks
REFCLK
SOUT
SIN
SS_CLKOUT
SS_CLKIN
SERDES(HSI#A)
CAL
CSLOCK
SERDES(HSI#B)
SOUT
SIN
TXD
RXD
RECCLK
SYDT
10
10
TXD
RXD
RECCLK
SYDT
10
10
To PICs
To PICs
To PICs
To PICs
To PICs
To PICs
From PICs
From PICs
From Global
Clock Tree
sysIO
From PICs
To PICs
CDRRST
From PICs
CDRRST
From PICs
Deserializer and Clock/Data Recovery
CSPLL
Serializer
Serializer
Deserializer and Clock/Data Recovery
