1 Programming of FPGA in LiCAS ADC for Continuous Data Readout Week 3 Report Jack Hickish

2 Progress Last Week Successfully compiled new code for the FPGA to facilitate constant data processing. Namely: - Modified (simplified) data flow path - Modified acquisition and read / write controls

3 Since then… Simulation - Check that external input changes between FFI and FSI mode as desired - Check that data out of FPGA has followed correct data path - Check for correct (continuous) operation of FFI mode. (and verify that FSI mode still functions correctly)

4 Obstacles to Simulation FFI Operation Data In RAM Internal FIFO Data Out over USB Sampling / Manipulation of data External FIFO FSI Operation Internal FIFO couldn’t (wouldn’t) be simulated. Data channels into the FIFO could be checked – simulations suggest data is being routed successfully but cannot verify altered read / write controls for FIFO

5 Other Simulation Results - FPGA will acquire data continuously when in FFI mode and successfully route data to FIFO - FPGA will switch between FFI and FSI operation modes when an external signal is applied (this signal has been integrated into the current USB “DAQ” software) - FPGA “Test” feature works in both modes of operation

6 Experimentation Next stage is experimentation with an FPGA loaded with new program - Input signal via a signal generator, monitored by oscilloscope - Output signals analysed with “DAQ” software - Internal signals monitored with “Chipscope” software

7 Results so far Existing ADC board in FSI operation

8 Results so far ADC board FPGA implemented with new code Generated signal 1MHz sin wave, ~1V amplitude Successes: - Data is going in and coming out (both FSI and FFI mode) Failures: - Output appears not to be a sign wave. Possible causes: New USB control software doesn’t graph properly. Input is 1MHz, allowing for only 3 samples per period.

9 Results so far ADC board FPGA implemented with new code Generated signal 800kHz sin wave, ~1V amplitude Below 1MHz input sin wave frequency, board only outputs noise. This happens in both FFI and FSI mode, on both new and original versions of DAQ software and is dependent only on signal generator frequency. ???

10 The week ahead -Fix DAQ graphing facility -Test low frequency sin wave input using 1) New FPGA code on a different board 2) Original code in current board -Use chipscope to check internal signals - Fact that FFI and FSI mode both output signal suggests either 1) Both modes are routing data correctly 2) Signal to change between modes isn’t doing anything! (software simulation suggests this isn’t the case) -Continuous operation