The Sci-Compiler SMART kit is a tool for non-expert users who are approaching the FPGA programming. We introduce them to an innovative method to simplify the firmware development. This method is based on Sci-Compiler software, a block-diagram-based programming interface consisting of a prebuilt set of functions (for example oscilloscope, TDC, MCA, charge integration, etc.) specifically developed for physics/engineering applications. Placing and interconnecting the available blocks on a diagram, Sci-Compiler is able to automatically generate a VHDL peace of code that implements the required function and deploy it to the FPGA. In this way, even a non-expert user can write his own firmware code without having any knowledge of the VHDL/Verilog programming language.
The Sci-Compiler SMART kit is composed of a Sci-Compiler license and a basic hardware (DT1260 unit), designed for the exact purpose of evaluating the software and learning how to design custom firmware using the block-diagram method. It includes:
- 1x DT1260, 2 Channel, 60 MS/s, 12 bit ADC unit with Open FPGA – also named SciDK board
- 1x Sci-Compiler Lite license working with the DT1260 unit only
The Sci-Compiler software, in combination with DT1260, allows to develop both FPGA firmware for *custom digital pulse processing- and software application for data readout, using the generated libraries. It is thus possible to access registers of the DT1260 and transfer data to the PC in list, waveform or user-customizable format.
The user can take advantages of examples firmware diagram available in the Sci-Compiler, in order to start learning how to program the FPGA and take confidence with the software.
The DT1260 is a dual channel, open FPGA Flash ADC unit. The core of the system is a programmable Spartan 7 LX25 FPGA, compatible with Sci-Compiler software tool.
Its main features are:
- 2x Analog input channels on LEMO connectors
- 60 MS/s, 12-bit ADC
- Spartan7-LX25 Open FPGA
- Single-ended analog front-end with configurable analog offset
- 10k/50 Ω selectable analog impedance
- 2x Programmable Digital I/Os
- USB2 High Speed Communication Interface
- Power on USB
- 2x Programmable User LEDs
- Factory-programmed fast bootloader
- Low Power Consumption < 2W
The memory hosted onboard is sufficient to implement even complex algorithm, for example a trapezoidal filter for energy reconstruction. There is no extenal RAM on the board, therefore the maximum wavelength is limited by the amount of RAM available in the device. In any case, at least 500us per channel buffer can be allocated.
The analog input is directly connected to the input front-end, i.e. a buffer with offset regulation connected on the inverting input. The analog input is by default connected to ground with a 10kΩ resistor. A 50Ω termination can be set by opening the box and inserting the jumpers
The analog input offset can be regulated via the integrated 12-bit DAC. SCI- Compiler exports by default an ANALOG_OFFSET DAC register. The 12-bit value written in the register is directly transferred to the DAC. As a result, the offset value is calibrated to move the ADC baseline to the value written in the register. For example if you write 2048, you will have the baseline at about 2000 level (over a total of 4096).
The input dynamic of the device is 2 Vpp: a 0 V signal will appear nearly at 2048 levels, 2048 to 4095 are for positive signals while from 2048 down to 0 are for negative signals. If the input signal is positive only, it is possible to cover the entire input dynamic using an offset nearly at 0; while, if the input signal is bipolar, the offset should be set to 2048 in order to have symmetrical dynamic.
Two 60 MS/s 12-bit ADCs convert the analog signal in digital data provided by the firmware in the FPGA. Two programmable digital I/Os are available. Their direction (input or output) is programmable within the firmware block diagram in Sci-Compiler.
The firmware is stored in a 128 Mbit Flash. The first part of the Flash is pre-programmed with a bootloader which is not accessible to the user. The rest of the flash can be programmed by SCI- Compiler to store the user firmware.
There are two user LEDs for general purpose usage. The LEDs can be driven as defined by the user in the firmware designed in Sci-Compiler.
