Anchor Electronics sells a selection of new and surplus Demand Peripherals boards. The project described on this page gives Anchor customers a quick, visual introduction to the Demand Peripherals product line and and open-source peripherals.

This page is organized as follows:

• Peripheral and hardware selection
• Physical construction and wiring notes
• Linux configuration
• Applications
  • distance
  • rgbled
  • demomotor

Our goal was to give Anchor customers a simple demonstration of the capabilities of the Demand Peripherals software defined peripherals. There are three separate applications running on the demo system.

The first is an ultrasonic distance sensor whose reading are displayed on a 6 digit LCD. The distance is shown in inches and tenths of an inch. We use the us8 peripheral (us8) and card (us8). The distance is shown in inches using the lcd6 peripheral (lcd6) and the lcd6 card (lcd6). The sensor is an Adafruit HC-SR04 (HC-SR04).

The second application uses a quad slide potentiometer peripheral (slide4) and card (slider4) to control the red-green-blue brightness of a string of eight WS2812 LEDs from Adafruit (NeoPixel Stick).

The third application uses a rotary encoder to control the speed and direction of a DC motor. The RPM speed of the motor is displayed on a second 6 digit LCD. The rotary encoder peripheral and card are the rotary encoder interface (roten) and the rotary encoder card(roten). We use a DC gearhead motor from Adafruit (Geared DC Motor). The motor is controlled with the dual DC motor controller peripheral (DC2) and the dual H-bridge card (d7hb). The motor has a magnetic quadrature encoder to measure the speed. The encoder outputs go to a general purpose IO card (gpio4) and from there to a dual quadrature decoder peripheral (quad2). A second LCD6 card and peripheral display the speed of the motor in revolutions per minute.

The command 'dplist' shows the peripherals in the system and the names of the resources available for each peripheral. The dplist for this project is shown below. Use the 'Build your FPGA Image' page (FPGA Image to request an FPGA binary with the listed peripheral. Of course you can change the requester peripherals and you can build the image from the Verilog sources if you wish.

  Slot/Name         Description
   0 / enumerator   FPGA Interface and ROM contents
                  - port : dpget dpset 
                  - text : dpget 
   1 /      bb4io   The buttons and LEDs on the Baseboard
                  - buttons : dpget dpcat 
                  - leds : dpget dpset 
   2 /        us8   Octal interface to SRF04 distance sensor
                  - distance : dpcat 
                  - enable : dpget dpset 
   3 /       lcd6   Six digit 7-segment LCD display
                  - display : dpget dpset 
                  - segments : dpget dpset 
   4 /       ws28   Quad WS2812 LED driver
                  - led : dpset 
                  - config : dpget dpset 
   5 /     slide4   Quad slide potentiometer
                  - positions : dpget dpcat 
   6 /      quad2   Dual Quadrature Decoder
                  - counts : dpcat 
                  - update_period : dpget dpset 
   7 /        dc2   Dual DC motor controller
                  - mode0 : dpget dpset 
                  - mode1 : dpget dpset 
                  - power0 : dpget dpset 
                  - power1 : dpget dpset 
                  - pwm_frequency : dpget dpset 
                  - watchdog : dpget dpset 
   8 /      roten   General purpose rotary encoder input
                  - encoder : dpget dpcat 
                  - led : dpget dpset 
   9 /       lcd6   Six digit 7-segment LCD display
                  - display : dpget dpset 
                  - segments : dpget dpset 
  10 /      gpio4   Quad General Purpose Input/Output
                  - pins : dpget dpset dpcat 
                  - direction : dpget dpset 
                  - interrupt : dpget dpset