ZEBRA

Tom Cobbpresented by Nick Rees

What is a zebra?

• Zebras (/ˈzɛbrə/ ZEB-rə or /ˈziːbrə/ ZEE-brə)[1] are several species of African equids (horse family) united by their distinctive black and white stripes.

What is ZEBRA?

• A digital signal level converter and position compare box

• 1U metal box with front panel BNCs and Lemos and rear panel encoder inputs

What does ZEBRA do?

• Takes front panel single channel inputs–TTL, LVDS, PECL, NIM, Open Collector

• And rear panel encoder signals–A+B RS422 Quadrature decoder, Z, connected

• Pass the signals through some FPGA logic–Logic gates, position compare circuitry

• Ouput front and rear panel signals–Same format as inputs, rewirable at run time

FPGA Design

Communications(8-bit soft Micro Controller)

Logic Control

PositionCompare

SRAMCtrl

UARTCtrl

Spartan-6 FPGA

RS23216 Mbit

SPIFlash

2MBx8SRAM

12 x LVTTL Inputs

12 x LVTTL outputs

4 Ch x RS422 outputs

4 Ch x RS422 Inputs

256x16 Config BRAMctrl

arm/gate/pulse

ctrl

rs422 signals

How do you configure ZEBRA?

• 115200 baud RS232 link to EPICS• Parameters set/get via EPICS• Logic blocks rewired via the system bus• Data download of position/time information• Save to internal flash

The System Bus

AND/OR Blocks

GATE Blocks

DIV Blocks

PULSE Blocks

QUAD Block and Encoders

PC Setup

PC Plot

What doesn’t ZEBRA do?

• Analogue• Signals < 20ns• Low latency data transfer• High bandwidth data transfer• Sequencing

When can I have one?

• Available from Quantum Detectors• http://

www.quantumdetectors.com/products/zebra

• Should be in stock by Christmas

Ideas for Zebra2• Ethernet interface

• TCP not UDP, so...

• Zinq, rather than Spartan6• IOC on board(?)

• Additional encoder capture/trigger signals:• Analogue input• Serial encoder input• Event reciever (?)

• Better support for counters• Differences?

• More gates