CrossLink Hardware Checklist

CrossLink Hardware Checklist
Preliminary Technical Note
TN1302 Version 1.0
May 2016
CrossLink Hardware Checklist
Preliminary Technical Note
Contents
Acronyms in This Document ................................................................................................................................................. 3
1. Introduction .................................................................................................................................................................. 4
2. Power Supplies ............................................................................................................................................................. 5
3. CrossLink MIPI D-PHY and PLL Power Supplies ............................................................................................................. 5
4. Power Estimation .......................................................................................................................................................... 6
5. Configuration Considerations ....................................................................................................................................... 6
6. Power Management Unit ............................................................................................................................................. 6
7. Clock Inputs .................................................................................................................................................................. 7
8. Pinout Considerations................................................................................................................................................... 7
8.1.
LVDS Pinout Considerations ................................................................................................................................ 7
8.2.
MIPI D-PHY Interface Considerations .................................................................................................................. 7
9. Checklist Table .............................................................................................................................................................. 8
References ............................................................................................................................................................................ 9
Technical Support Assistance ............................................................................................................................................... 9
Revision History .................................................................................................................................................................... 9
Tables
Table 2.1. CrossLink FPGA Power Supplies ...........................................................................................................................5
Table 5.1. Required Pull-up/Pull-down Resistors for Configuration Pins .............................................................................6
Table 5.2. Configuration Pins Needed per Programming Mode ...........................................................................................6
Table 9.1. Checklist Table .....................................................................................................................................................8
© 2015-2016 Lattice Semiconductor Corp. All Lattice trademarks, registered trademarks, patents, and disclaimers are as listed at www.latticesemi.com/legal. All other brand or product names are
trademarks or registered trademarks of their respective holders. The specifications and information herein are subject to change without notice.
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CrossLink Hardware Checklist
Preliminary Technical Note
Acronyms in This Document
A list of acronyms used in this document.
Acronym
DDR
2
IC
LVDS
NVCM
PCB
PLL
SPI
WLCSP
Definition
Double Data Rate
Inter-Integrated Circuit
Low-Voltage Differential Signaling
Non-Volatile Configuration Memory
Printed Circuit Board
Phase Locked Loop
Serial Peripheral Interface
Wafer Level Chip Scale Package
© 2015-2016 Lattice Semiconductor Corp. All Lattice trademarks, registered trademarks, patents, and disclaimers are as listed at www.latticesemi.com/legal. All other brand or product names are
trademarks or registered trademarks of their respective holders. The specifications and information herein are subject to change without notice.
TN1302-1.0
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CrossLink Hardware Checklist
Preliminary Technical Note
1. Introduction
When designing complex hardware using the Lattice Semiconductor CrossLink™ FPGA, designers must pay special
attention to critical hardware configuration requirements. This technical note steps through these critical hardware
implementation requirements related to the CrossLink device. The document does not provide detailed step-by-step
instructions but gives a high-level summary checklist to assist in the design process.
This technical note assumes that the reader is familiar with the CrossLink device features as described in DS1055,
CrossLink Family Data Sheet.
The critical hardware areas covered in this technical note include:
 Power supplies as they relate to the CrossLink power supply rails and how to connect them to the PCB and the
associated system
 Configuration mode selection for proper power-up behavior
 Device I/O interface and critical signals
The data sheet includes the functional specification and electrical characteristics for the device.
Topics covered in the data sheet include but are not limited to the following:
 High-level functional overview
 Pinouts and packaging information
 Signal descriptions
 Device-specific information about peripherals and registers
 Electrical specifications
Important: Refer to the following documents for detailed recommendations.
 TN1301, CrossLink High-Speed I/O Interface
 TN1303, CrossLink Programming and Configuration Usage Guide
 TN1304, CrossLink sysCLOCK PLL/DLL Design and Usage Guide
 TN1305, CrossLink sysI/O Usage Guide
 TN1306, CrossLink Memory Usage Guide
 TN1307, Power Management and Calculation for CrossLink Devices
 TN1308, CrossLink I2C Hardened IP Usage Guide
 TN1309, Advanced CrossLink I2C Hardened IP Reference Guide
 TN1068, Power Decoupling and Bypass Filtering for Programmable Devices
© 2015-2016 Lattice Semiconductor Corp. All Lattice trademarks, registered trademarks, patents, and disclaimers are as listed at www.latticesemi.com/legal. All other brand or product names are
trademarks or registered trademarks of their respective holders. The specifications and information herein are subject to change without notice.
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TN1302-1.0
CrossLink Hardware Checklist
Preliminary Technical Note
2. Power Supplies
The CrossLink internal Power Good condition is determined by the VCC, VCCAUX25VPP and VCCIO0 power supplies. These
supplies need to be at a valid and stable level before the device becomes operational. Several other supplies including
VCC_DPHY, VCCA_DPHY, VCCPLL_DPHY, VCCMU_DPHY are used in conjunction with on-board D-PHYs on CrossLink devices.
Table 2.1 describes the power supplies and the appropriate voltage levels for each supply.
Table 2.1. CrossLink FPGA Power Supplies
Supply
Voltage
(Nominal Value)
Description
VCC
1.2 V
FPGA core power supply. Required for Power Good condition.
VCCGPLL
1.2 V
General Purpose PLL Supply Voltage. Should be isolated from excessive noise.
VCCAUX25VPP
2.5 V
Auxiliary Supply Voltage for Bank 1, 2 and NVCM Programming. Required for Power
Good condition.
VCCIO[2, 1, 0]
1.2 V to 3.3 V
VCC_DPHY[1,0]
1.2 V
Digital Supply Voltage for D-PHY. Should be isolated from excessive noise.
VCCA_DPHY[1,0]
1.2 V
Analog Supply Voltage for D-PHY. Should be isolated from excessive noise.
VCCPLL_DPHY[1,0]
1.2 V
PLL Supply voltage for D-PHY. Should be isolated from excessive noise.
VCCMU_DPHY1
1.2 V
WLCSP36 package only: VCC_DPHY1, VCCA_DPHY1 and VCCPLL_DPHY1 ganged together. Should be
isolated from excessive noise.
I/O Driver Supply Voltage for Bank 0, 1, or 2. Each bank has its own VCCIO supply: VCCIO0
is used in conjunction with pins dedicated and shared with device configuration, and is
required for Power Good condition.
The CrossLink FPGA device has a power-on-reset state machine that depends on several of the power supplies.
These supplies should come up monotonically. A power-on-reset counter begins to count after VCC, VCCAUX25VPP and
VCCIO0 reach the levels defined in the Power-On-Reset Voltage Levels section of DS1055, CrossLink Family Data Sheet.
Initialization of the device does not proceed until the last power supply has reached its minimum operating voltage.
3. CrossLink MIPI D-PHY and PLL Power Supplies
Supplies dedicated to the operation of the CrossLink MIPI® D-PHY include VCCA_DPHYx, VCCPLL_DPHYx, and VCCMU_DPHY1.
These pins are also paired with dedicated ground pins including GNDA_DPHYx and GNDPLL_DPHYx. These supplies
should be decoupled with adequate bypass capacitors between these pins, close to the device package.
The VCCGPLL provides a quiet supply for the general purpose PLL while the VCCPLL_DPHYx and VCCA_DPHYx provide a quiet
supply for the critical MIPI D-PHY blocks. For the best jitter performance, careful pin assignment will keep noisy I/O pins
away from sensitive functional pins. The leading causes of PCB related MIPI D-PHY crosstalk is related to FPGA outputs
located in close proximity to the sensitive MIPI D-PHY power supplies. These supplies require cautious board layout to
ensure noise immunity to the switching noise generated by FPGA outputs. Guidelines are provided to build quiet
filtered supplies for the analog supplies, however robust PCB layout is required to ensure that noise does not infiltrate
into these analog supplies. See the list of recommended documents in the Introduction section for more details.
© 2015-2016 Lattice Semiconductor Corp. All Lattice trademarks, registered trademarks, patents, and disclaimers are as listed at www.latticesemi.com/legal. All other brand or product names are
trademarks or registered trademarks of their respective holders. The specifications and information herein are subject to change without notice.
TN1302-1.0
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CrossLink Hardware Checklist
Preliminary Technical Note
4. Power Estimation
After deciding the CrossLink, package and logic implementation, power estimation for the system environment should
be determined based on the software Power Calculator provided as part of the Lattice Diamond ® design tool. When
estimating power, the designer should keep two goals in mind:
 Power supply budgeting should be based on the maximum of the power-up in-rush current, configuration current
or maximum DC and AC current for the given system’s environmental conditions.
 The ability for the system environment and CrossLink device packaging to be able to support the specified
maximum operating junction temperature. By determining these two criteria, the CrossLink device power
requirements are considered early in the design phase.
5. Configuration Considerations
2
The CrossLink device includes provisions to configure the FPGA from a processor via Slave I C or Slave SPI, Master SPI
from an external SPI Flash, or internally from NVCM.
The use of external resistors is always needed if the configuration signals are being used to handshake to other devices.
For Master SPI mode, the MCK pin must be connected to a serial 30 Ω resistor placed close to the CrossLink device
package, to prevent reflections or glitches during Master SPI configuration. Recommended 4.7K pull-up resistors to
VCCIO0 and pull-down to board ground should be used on the following pins.
Table 5.1. Required Pull-up/Pull-down Resistors for Configuration Pins
Pin
PCB Connection
CRESET_B
4.7K Pull-up to VCCIO0
CDONE
4.7K Pull-up to VCCIO0
SDA
Strong Pull-up (Open Drain Signal)*
SCL
Strong Pull-up (Open Drain Signal)*
SPI_SS
4.7K Pull-up to VCCIO0 (Open Drain Signal)
MCK
30 Ω Serial Resistor close to CrossLink package
2
2
*Note: Pull-up value on I C signals is dependent on the I C bus characteristics and programming speed. Typical values are between
2.2K and 4.7K.
Table 5.2. Configuration Pins Needed per Programming Mode
Configuration Mode
Clock
Pin
I/O
Shared Pins
Dedicated Pins
SSPI
SPI_SCK
Input
MISO, MOSI, SPI_SS
CRESET_B
MSPI
MCK
Output
MISO, MOSI, CSN
CRESET_B
I2C
SCL
Input
SDA
CRESET_B
6. Power Management Unit
The CrossLink device includes a dedicated Power Management Unit which may place the fabric and other on-chip
resources into sleep mode. CrossLink includes a dual function pin called PMU_WKUPN. This pin is active low and may
be used to wake-up the device from sleep mode. A weak pull-up resistor (10K – 100K) is recommended when the pin is
assigned to the wakeup function.
© 2015-2016 Lattice Semiconductor Corp. All Lattice trademarks, registered trademarks, patents, and disclaimers are as listed at www.latticesemi.com/legal. All other brand or product names are
trademarks or registered trademarks of their respective holders. The specifications and information herein are subject to change without notice.
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TN1302-1.0
CrossLink Hardware Checklist
Preliminary Technical Note
7. Clock Inputs
The CrossLink device provides primary clock input pins, which are shared function pins that can also be used as general
purpose I/O. When these pins are used for clocking purpose, the user needs to pay attention to minimize signal noise
on these pins.
8. Pinout Considerations
The CrossLink device is designed to support high-speed video interface bridging. This includes various rule-based
pinouts that need to be understood prior to implementation of the PCB design. The pinout selection must be
completed with an understanding of the interface building blocks of the FPGA fabric. These include I/O Logic blocks
such as DDR, clock resource connectivity and PLL usage. Refer to TN1301, CrossLink High-Speed I/O Interface for rules
pertaining to these interface types.
8.1. LVDS Pinout Considerations
True LVDS inputs and outputs are available on I/O pins in Banks 1 and 2. These multi-function I/O pins support LVDS,
LVCMOS, subLVDS, SLVS, and MIPI D-PHY receive functions. The I/O buffers are described in TN1305, CrossLink sysI/O
Usage Guide.
8.2. MIPI D-PHY Interface Considerations
Although coupling has been reduced in the device packages of CrossLink devices so that little crosstalk is generated, the
PCB board can cause significant noise injection from any I/O pin adjacent to MIPI D-PHY data, reference clock, and
power pins as well as other critical I/O pins such as clock signals. PCB traces running in parallel for long distances need
careful analysis. Simulate any suspicious traces using a PCB crosstalk simulation tool to determine if they can cause
problems.
High-speed signaling requires careful PCB stackup and layout design. Maintaining good transmission line characteristics
and impedance controlled routing is a must requirement to achieve higher bandwidth. A solid ground reference plane
shall be maintained underneath of high-speed signal routing. This includes tightly matched differential routing with
very few discontinuities. Matching between the D-PHY clock and data pairs is especially critical. Refer to TN1033, HighSpeed PCB Design Considerations, for suggested methods and guidance.
© 2015-2016 Lattice Semiconductor Corp. All Lattice trademarks, registered trademarks, patents, and disclaimers are as listed at www.latticesemi.com/legal. All other brand or product names are
trademarks or registered trademarks of their respective holders. The specifications and information herein are subject to change without notice.
TN1302-1.0
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CrossLink Hardware Checklist
Preliminary Technical Note
9. Checklist Table
Table 9.1. Checklist Table
1
1.1
1.1.1
Item
FPGA Power Supplies
VCC core voltage @ 1.2 V ±5%
Use a PCB plane for VCC core voltage with proper decoupling.
1.1.2
1.2
VCC core supply sized to meet power requirement calculation from software.
VCCGPLL @ 1.2 V ±5%
1.2.1
VCCGPLL isolated from excessive noise.
1.2.2
1.3
VCCIO0 voltage matches external configuration interfaces (that is memory devices).
1.3.2
VCCIO0, VCCIO1, VCCIO2 voltage based on user design.
2
2.1
VCCAUX25VPP @ 2.5 V ±5%
MIPI D-PHY Power Supplies
VCCA_DPHYx @ 1.2 V ±5%. Should be ganged together and a solid PCB plane is recommended. This plane
should not have adjacent non-MIPI D-PHY signals passing above or below. It should also be isolated from
the VCC core power plane.
2.2
VCCPLL_DPHYx @1.2 V ±5% “clean” and “isolated”
2.3
VCCMU_DPHYx @1.2 V ±5% – follow recommendations for VCCA_DPHY.
3
3.1
3.2
3.3
4
4.1
4.1.1
4.1.2
4.2
4.2.1
4.2.2
4.2.3
4.2.4
5
5.1
5.2
6
6.1
NA
VCCGPLL pins should be ganged together and a solid PCB plane is recommended. This plane should not have
adjacent non-MIPI D-PHY signals passing above or below. It should also be isolated from the VCC core
power plane.
All VCCIO voltages are between 1.2 V to 3.3 V
1.3.1
1.4
OK
Configuration/Power Management Unit
Pull-ups and pull-downs on configuration specific pins as given in Table 5.1.
VCCIO0 bank voltage matches sysCONFIG peripheral devices such as SPI Flash.
PMU_WKUPN pull-up (when used to wake up the device).
MIPI D-PHY
Dedicated reference clock input from clock source meets the DC and AC requirements.
External AC-coupling caps may be required for compatibility to common-mode levels.
Reference clock termination resistors may be needed for compatible signaling levels.
Maintain good high-speed transmission line routing.
Continuous ground reference plane to serial channels.
Length matched differential traces.
Do not pass other signals on the PCB above or below the high-speed MIPI D-PHY signals traces without
isolation.
Keep non-MIPI D-PHY signal traces from passing above or below the 1.2 V VCCA_DPHY power plane without
isolation.
Critical Pinout Selection
Pinout has been chosen to address FPGA resource connections to I/O logic and clock resources per
TN1301, CrossLink High-Speed I/O Interface.
FPGA PLL, MIPI D-PHY PLL, and clock inputs assigned to proper pins per device DS1055, CrossLink Family
Data Sheet.
2
IC
2.2K – 4.7K Pull-up on open drain signals SCL and SDA.
© 2015-2016 Lattice Semiconductor Corp. All Lattice trademarks, registered trademarks, patents, and disclaimers are as listed at www.latticesemi.com/legal. All other brand or product names are
trademarks or registered trademarks of their respective holders. The specifications and information herein are subject to change without notice.
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TN1302-1.0
CrossLink Hardware Checklist
Preliminary Technical Note
References
For more information, refer to the following documents:
 DS1055, CrossLink Family Data Sheet
 TN1301, CrossLink High-Speed I/O Interface
 TN1303, CrossLink Programming and Configuration Usage Guide
 TN1304, CrossLink sysCLOCK PLL/DLL Design and Usage Guide
 TN1305, CrossLink sysI/O Usage Guide
 TN1306, CrossLink Memory Usage Guide
 TN1307, Power Management and Calculation for CrossLink Devices
 TN1308, CrossLink I2C Hardened IP Usage Guide
 TN1309, Advanced CrossLink I2C Hardened IP Reference Guide
 TN1033, High-Speed PCB Design Considerations
 TN1068, Power Decoupling and Bypass Filtering for Programmable Devices
Technical Support Assistance
Submit a technical support case through www.latticesemi.com/techsupport.
Revision History
Date
Version
May 2016
1.0
Change Summary
First preliminary release.
© 2015-2016 Lattice Semiconductor Corp. All Lattice trademarks, registered trademarks, patents, and disclaimers are as listed at www.latticesemi.com/legal. All other brand or product names are
trademarks or registered trademarks of their respective holders. The specifications and information herein are subject to change without notice.
TN1302-1.0
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