Cute-WR-A7

(Compact Universal Timing Endpoint Based on White Rabbit with Xilinx Artix7)

Introduction

The Cute-WR series are standalone White Rabbit Node implementations on FPGA Mezzanine Card form factor. The idea is to have a compact, low-cost and common WR NIC for synchronous DAQ front-ends and other applications! Cute-WR shows the feasibility of the idea; while the Cute-WR-DP expands the Cute-WR to two SFP ports that can support various operation modes. The Cute-WR-A7 is the enhanced version of the CUTE-WR-DP with an Xilinx Artix7 series FPGA. It inherits similar interfaces from Cute-WR-DP: two SFP ports, two SMA/LEMO connectors, FMC form factor with LPC connector, etc.

The three operation modes of Cute-WR-DP are also supported by Cute-WR-A7:

1. Normal mode (Cute-WR-A7-NM)
   • In Normal mode, Cute-WR-A7 acts as a normal WR node with one SFP port (SFP0).
2. Cascade mode (Cute-WR-A7-CM)
   • In CM mode, two ports act as one down-link (SFP1) and one up-link (SFP0) to support cascade topology. Two ports also support a simple switch function for normal Ethernet packets.
3. Parallel mode (Cute-WR-A7-PM)
   • In PM mode both ports act as down-link port connect to different WRS, provide redundancy to improve the reliability for safety related applications. The current firmware doesn't support this function.

Hardware

    **Cute-WR-A7 Block diagram**

Cute-WR-A7

Cute-WR-A7 with heatsink

Hardware Features:

• XC7A35T-2CSG325I (XC7A50T-2CSG325I compatible)
• Two SFP sockets that support WR
• 128Mb QSPI FLASH (N25Q128A13ESE40F)
• 512Kb I2C EEPROM (24FC512-I/SM)
• UART port (TTL level with 3-state buffer)
• VITA57 FMC mezzanine with LPC connector
• Ruggedized conduction cooled form factor
• AD9516 for the main PLL
• Mounting options for various VCXOs
• Two delay adjustable output channels (11ps increments, 6ns range)
• 1-Wire Temperature sensor
• Current sensor
• 2 LEMO/SMA for the delay adjustable output
• 4 front panel LEDs or two bi-color LEDs
• 3.3v power supply, 2.5A

Firmware

The firmware of Cute-WR-A7 is similar with the Cute-WR-DP, it is based on WRPC with modified code in the LM32 softcore. The additional resource cost to support Dual Port is less than twice that of a single port.

• [Firmware (Vivado project)] https://ohwr.org/project/wr-cores/tree/thu-cute-dp-a7

project file location: https://ohwr.org/project/wr-cores/tree/thu-cute-dp-a7/syn/cute_a7_ref_design

• [Software (lm32 code)] https://ohwr.org/project/wrpc-sw/tree/thu-cute-dp-a7

Please refer to wr official manual to compile the firmware and software.

Evaluation board

As a FMC mezzanine, the Cute-WR-A7 is not supposed to work alone thus a carrier board is always expected. A evaluation board with FMC socket, power supply, USB-UART converter and LED can simplify the development setup of Cute-WR-A7.

Cute-WR-A7 EVB

Project information

Users list

• SHINE

Contacts

Commercial producers

• Cute-WR-A7 - SyncTechnology - a spinoff company from THU, China

General question about project

• Guanghua Gong - ggh@tsinghua.edu.cn Tsinghua University, Beijing

Status

14 September 2020