USB Live Oscilloscope: Digital Input Board


Posted on Feb 5, 2014

The digital input board has 8 distinct digital inputs available on JP1. There are separate pull-down resistors (RN1, choose a value you like, e. g. 1MOhm) and then each input has a Schmitt-trigger. Since these may be destroyed by improper input voltages, I chose to use HC14 devices in DIL-14 packages and mount them on sockets to be easily replaceab


USB Live Oscilloscope: Digital Input Board
Click here to download the full size of the above Circuit.

le. Furthermore, one can switch from CMOS to TTL levels by plugging in a HCT14 instead or even have mixed inputs since there are two Schmitt-trigger IC`s, each one handling 4 inputs. The inputs operate on 5V or 3. 3V levels; for the latter, there is an on-board LDO (IC5) which generates the 3. 3V from 5V. This is not strictly necessary since we already have 3. 3V on the mainboard (available on the AD_DUMMY connector, actually. ), so you may choose to go for a simpler design. Note that when configuring for 3. 3V inputs, the digital bus voltage at pin1 on ADCV_DATA must be 3. 3V, otherwise 5V are supported as well (although we exclusively use 3. 3V for the USB Live Oscilloscope).




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    IR repeater with 555 timer
    Security Lock with keypad and LCD (PIC16F84A)
    Smoke-detector
    Low-frequency-oscillator
    Preregulated-high-voltage-supply
    Light Sensor Circuits
    RFI-Free Ringer Generator Works Off Single 5-V Supply
    Digital tachometer using 8051
    solar charge
    AH1751-P HALL EFFECT LATCH
    A small FM transmitter (SMD)s
    Motor Bike Headlight Controller Circuit
    12 volt power supply circuit diagram using LT3845
    Process-Control
    Spice and the art of preamplifier design
    RF VOLTMETER
    Circuit diagram of an analog circuit PWM



    Top