Update on JEM FPGA coding

Carsten NödingJohannes Gutenberg-Universität Mainz JEM block diagramm

Carsten NödingJohannes Gutenberg-Universität Mainz Input FPGA Changes since Birmingham Meeting: 256 slices deep playback memory can be written via consecutive single word transfers and read back code clean-up

Carsten NödingJohannes Gutenberg-Universität Mainz Main Processor

Carsten NödingJohannes Gutenberg-Universität Mainz E T,miss, E T

Carsten NödingJohannes Gutenberg-Universität Mainz Main Processor (1) Changes since Birmingham Meeting (only RTDP of energy tree): code clean-up Past: Conversion into E X and E Y was done in 16 LUT based multipliers using ROMs  Only changeable by loading a new configuration  Handling of INIT values for LUTs is annoying Latency of RTDP: 3 bunch crossings MHz, 25 % logic resources XCV600E-7-FG680C) [Logic resources needed for jet tree: %] Present: Multiplication is done using Block SelectRAM capabilities of Virtex-E  Changeable via consecutive VME read/write access  Easier handling, code easier to understand Latency: 4 bunch crossing MHz, 15 % logic resources of XCV600E- 7-FG680C)

Carsten NödingJohannes Gutenberg-Universität Mainz Main Processor (2) Future: Use Virtex-II device as Main Processor: Multiplication can done using embedded 18bit by 18bit multipliers  Accuracy is not worsened  Code can be easily adapted (just throw away half of it)  Latency: 2.5 bunch crossings

Carsten NödingJohannes Gutenberg-Universität Mainz Reorganisation of JEM Programming Model Changes since Birmingham Meeting: Added gaps in register offsets (especially around blocks of related ones, eg. jet thresholds)  things can be changed in the future without having to change the offsets used in any existing software  registers which belong together start at some nice boundary Module ID words start at address 0 of the module Added multiplication registers to store E T sin() and E T cos() results in BlockRAMs (Virtex-E)  same register can be used for storing sin() and cos() in Virtex-II devices “separate registers for separate things”  Programming Model has been approved by Murrough  Current version can be found in the latest JEM PDR available on the web

Carsten NödingJohannes Gutenberg-Universität Mainz Outlook Main task now: Test of JEM prototype