USB Digital/Analogue Interface Board

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Product description

   Those of us in the UK who began their interest in electronics back in the 1980s will remember the BBC Micro computer and its powerful User Port, 1MHz BUS and Analogue interfaces. Modern computers lack these interface options and so we designed the USB Digital/Analogue Interface Board to rectify that situation.

   The USBINDEVM03 has been designed to offer a number of ports over a wide variety of interfacing options. The board can be powered directly from the USB bus or from an external 9v DC power supply. For any application that will need the board to supply more than 250mA we recommend using the external supply option.

   The board provides access to 16 latched digital outputs, 16 buffered digital inputs, an SPI bus with 4 device enable lines, a 4-channel 8-bit DAC, 2 separate 8-bit ADC and lastly a separate 4096 address 8-bit parallel data bus. All interfaces use 0v and 5v as digital logic and analogue signal references.

   The latest C++ Windows libraries and example programs are are available from our support section along with the compiled and source firmware. We do not have code available for *nix or Apple devices at present but this is something we're working on when we have time!

   This project is available for self-assembly but please be aware that almost all the components use surface-mount technology and need suitable tools for careful placement and soldering. A case for this project is not supplied; however it does come with rubber PCB feet for desk/worktop use in order to allow quick and easy access to the interfaces.

Product specifications

• Microcontroller: Microchip PIC18F4550

• Interface: USB 2.0 with a Mini-B socket

• Power: USB or External 9v PSU

  USB Only: Maximum 250mA

  External PSU: Maximum 500mA

  Board Operating Voltage: 5v

• Firmware: Bootloader or ISCP upgradable

• Indicators: Power (5v supply)

• Interfaces:

  Digital Output: 16 ports (latched)

  Digital Input: 16 ports (buffered)

  SPI: 1 Interface (SDI, SDO, SCK)
    -- 4 device enable lines

  Analogue Output (DAC): 4ch (8 bit from 0v to 5v)

  Analogue Input (ADC): 2ch (8 bit with internal voltage reference)

  8 bit data bus with 12 bit address bus
    -- Memory locations 0x0000 to 0x0FEF free for use
    -- Memory locations 0x0FF0 to 0x0FFF used by onboard devices

• Dimensions W x D x H in mm (inch) : 100 x 80 x 15 (3.94 x 3.15 x 0.59)