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tn1070_01

 

Evaluating the ORCA ORSO42G5 with the

High-Speed SERDES Board

 

April 2004

Technical Note TN1070

 

Introduction

 

Contained in this package is information that will assist you in evaluating and verifying your ORCA

 

®

 

 ORSO42G5

designs using the Lattice High-Speed SERDES Board and the ORCAstra system bus control panel (available for
download from the Lattice web site at www.latticesemi.com/products/devtools/software/orcastra/index.cfm).

The Lattice High-Speed SERDES Board supports a number of testing and evaluation setups for both the
ORT42G5 and the ORSO42G5. This document will cover some common types of evaluation testing that can be
performed on the ORSO42G5 device in SERDES-only and SONET modes. The tests include transmitter eye dia-
gram measurement, SONET Near-end Loop-back and SERDES-only, SONET and Aligned SONET Far-end Loop-
back. All of the described evaluation setups use the orso4_felb6.bit bitstream. This bitstream is included with the
package you have downloaded from the Lattice web site at www.latticesemi.com/products/devtools/hard-
ware/orso42g5-board/index.cfm. A unique ORCAstra macro is used to configure the device for each test.

 

PC and Evaluation Board Setup

 

This document assumes the ORCAstra application and bitstream programming software (ispVM

 

®

 

) are installed on

the user’s PC. It also assumes the baseline board configuration listed below. (The user is also encouraged to
experiment with other configurations.)

• All jumpers should be in their default position and default programming in the ispPAC

 

®

 

-POWR1208 as 

described in the Evaluation Board User Manual. This will apply power in the recommended sequence and 
provide 3.3V V

 

DDIO

 

 to all banks.

• ispDOWNLOAD

 

®

 

 cable (pDS4102-DL2) connected to the parallel port of the PC and to the ispVM connec-

tor on the board (J30). The pDS4102-DL2 is included with the Lattice High-Speed SERDES Board. Alter-
nately, a HW-USB-1A ispDOWNLOAD cable can be used.)

• ORCAstra connected to the parallel or USB port on the PC and the ORCAstra Interface DB-25 or USB con-

nector on the board (J108).

• External differential clock connected to the External System Clock SMA connectors (J87/J88 and J84/J85).
• External power should be provided from the Molex cable and power module.

 

Recommended Reading

 

• ORSO42G5 Data Sheet
• ORCA Series 4 FPGA Data Sheet
• ispVM System Software Data Sheet
• ispDOWNLOAD Cable Data Sheet
• High-Speed SERDES Briefcase Board User Manual
• ORCAstra System Bus Control Panel User Manual

 

Loop-back Description

 

Two types of high-speed loop-back are discussed in this document: Near-End Loop-back and Far-End Loop-back.
Near-End Loop-back (NELB) is defined as the data path from the FPGA Transmit into the SERDES and back
through the SERDES to the FPGA Receive as shown in Figure 1. The actual loop-back connection is made inter-
nally at the interfaces to the transmit and receive CML buffers of the ORSO42G5 device.

Summary of Contents for ORCA ORSO42G5

Page 1: ...umes the baseline board configuration listed below The user is also encouraged to experiment with other configurations All jumpers should be in their default position and default programming in the ispPAC POWR1208 as described in the Evaluation Board User Manual This will apply power in the recommended sequence and provide 3 3V VDDIO to all banks ispDOWNLOAD cable pDS4102 DL2 connected to the para...

Page 2: ...p back ORSO4_FELB6 Bitstream The orso4_felb6 bit design has been created as a base for all the described evaluation setups for the ORSO42G5 device As shown in Figure 3 the design takes advantage of the four SERDES channels available on the board The orso4_felb6 bitstream and the ORCAstra macros used in the tests are included in the package downloaded from www latticesemi com products devtools hard...

Page 3: ...servation and measurement of the data eye generated by the device The ORSO42G5 device s major mode will produce a SONET scrambled data eye The same experimental setup can be used for near end loop back tests Other data pattern eye diagrams can be measured using far end loop back setups discussed later in this docu ment In this example either channel AC or AD can be used to evaluate a SONET scrambl...

Page 4: ...ansmit Eye Diagram Setup Transmit Eye Diagram Test Procedures SONET Scrambled Data Eye 1 Connect the system as shown in Figure 4 The scope SMA cables should be connected to the HDOUTP_Bx and HDOUTN_Bx SMA connectors on the board 2 Power up the system 3 Start the clock generator and provide a nominal 155 52MHz CML reference clock 4 Download the orso4_felb6 bit bitstream into the ORSO42G5 5 Run the ...

Page 5: ... 3 Far end Loop back For a Far End Loop back FELB test using the ORSO42G5 device the reference clock for the ORSO42G5 and for the data source must be frequency locked This is a mandatory requirement since the ORSO42G5 transmitter always uses the local reference clock Three types of FELB can be performed with the ORSO42G5 device Each type uses a different data path for the transmit and receive bloc...

Page 6: ...tion 0xF6F6F6F628282828 SONET framing is established and the data is optionally descrambled After framing is established the aligned 32 bit data is transmitted to the FPGA along with a frame pulse DOUTBx_FP to indicate the start of the SONET frame The orso4_felb6 bit design uses an asynchronous FIFO to cross clock domains to the local reference clock REFCLK The data is then sent back into the embe...

Page 7: ...he data back to the transmit interface to the embedded ASIC core as 32 bit data and frame pulse DINBx_FP for each channel Inside the Tx SONET block TOH bytes are optionally inserted and the 32 bit data is optionally re scrambled The data is then sent through the MUX block converted back to 8 bits serialized and transmitted via the CML buffer Setup Requirements Far End Loop back Testing You will ne...

Page 8: ...ing the ORCAstra application SONET FELB 1 Connect the system as shown in Figure 8 The data SMA cables should be connected to the HDIN_Bx and HDOUTN_Bx SMA connectors on the board 2 Power up the system 3 Start the clock generator to provide a nominal 155 52MHz CML reference clock 4 Download the orso4_felb6 bit bitstream into the ORSO42G5 5 Run the sonet_felb fpm macro using the pull down menu in th...

Page 9: ...lication can be used to control this selection When AUTO_TOH mode is enabled the Tx SONET block inserts all of the TOH bytes in the SONET frame This mode overwrites any default TOH values If AUTO_TOH mode is used the SONET scrambler descrambler must also be used An AUTO_SOH mode can also be selected using the ORCAstra application In this mode A1 A2 and or B1 bits are optionally inserted by the cor...

Page 10: ...minated to ground they do not provide the required termination bias voltage When this equip ment is directly connected to the SERDES output it will provide an incorrect DC bias and prevents proper output buffer operation Inserting the bias tee module in the SERDES output connection to the oscilloscope allows the application of the required dc bias condition and provides the dc voltage translation ...

Page 11: ...cy ranges and DC cur rent levels from several different vendors Lattice uses a Picosecond Pulse Lab bias tee More detailed character ization and application documents are available from this vendor See the References section at the end of this document Q Can the SERDES output be observed without a bias tee module Yes in two different ways as shown below 1 For AC coupled SERDES interface applicatio...

Page 12: ...on voltage should be set to the VDDOB supply voltage used on the High Speed SERDES Board 1 5V if internal supply is being used This is the best means of observing the Tx data out put signals for DC coupled applications since it eliminates any possible signal degradation caused by bias tee and DC blocking elements References Bias Tee Model 5575A Picosecond Pulse Labs Boulder CO www picosecond com 5...

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