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Introduction

The A395E is a DAC (Digital-to-Analog Converter) expansion board for the V2495 that provides 8 low-speed 16-bit analog output channels.

A395E Board

The board can be installed in expansion slots D, E, or F of the V2495 mainboard. The FPGA controls the DAC via a simple write interface.

Product link: CAEN A395E

Pin Description

DAC_DATA Input 16 bit BIT VECTOR
16-bit digital value to be converted to analog. This value is latched to the selected channel when DAC_WR pulses HIGH.
DAC_CH Input 4 bit BIT VECTOR
Channel selection (4-bit value, 0-7 valid). Selects which of the 8 DAC channels will be updated.
DAC_WR Input 1 bit BIT
Write strobe. A LOW → HIGH transition latches DAC_DATA to the channel selected by DAC_CH.
DAC_TST Input 1 bit BIT
Test mode trigger. Set HIGH to start the DAC test procedure.
CLK Input 1 bit BIT
Default: Default Board Clock
RESET Input 1 bit BIT
Default: Default Board Reset

Properties

Property window

Socket Socket

Select the socket hosting the expansion board

Selects the expansion socket where the A395E is installed. Available options: D, E, F. Must match the physical installation location on the V2495 mainboard.

Default: D

Options: D E F

Usage

DAC Control Interface

The A395E is controlled through a simple serial-like interface:

  ┌──────────────────────────────────────────────────────────────────┐
│                      A395E DAC Interface                         │
│                                                                  │
│   ┌─────────────┐                  ┌─────────────┐               │
│   │   FPGA      │═══► DAC_DATA ═══►│             │               │
│   │   Logic     │═══► DAC_CH ═════►│   A395E     │═══► Analog    │
│   │             │═══► DAC_WR ═════►│  (8 ch)     │    Outputs    │
│   │             │═══► DAC_TST ════►│             │               │
│   └─────────────┘                  └─────────────┘               │
└──────────────────────────────────────────────────────────────────┘

Write Sequence

To update a DAC channel:

  1. Set DAC_DATA to the desired 16-bit value
  2. Set DAC_CH to the target channel (0-7)
  3. Pulse DAC_WR HIGH to latch the value

Test Mode

The DAC_TST signal initiates a test procedure for the DAC:

DAC_TST Function
LOW (0) Normal operation
HIGH (1) Start DAC test procedure

Expansion Socket Selection

Socket Description
D Expansion slot D
E Expansion slot E
F Expansion slot F

Signal Characteristics

Parameter Value
Channels 8
Resolution 16 bits
Type Low-speed DAC
Interface Parallel data + channel select + write strobe

Typical Usage

Use the A395E to generate:

  • Threshold voltages for discriminators
  • Bias voltages
  • Reference levels
  • Slow control signals

Resources & Timing

  • Latency: DAC settling time (see A395E datasheet)

  • Throughput: Low-speed updates (not for waveform generation)

  • 8 independent 16-bit DAC channels
  • Simple parallel interface
  • Suitable for threshold/bias generation

Supported Boards

  • V2495