Digital-Design (Page 4)

The glue/interface Logic families are many. TTL and CMOS is what we all know. TTL is made of the trusted NPN and PNP transistors. CMOS logic is made of Mosfets/FET types.

Making a Logical Choice in Speed-n-Power

CD40XX and Intersil chips were the first CMOS types of IC that became popular. The former were versatile Building Blocks and the Latter created what i would call Flexible Advanced Public ASICs.

CMOS are low power consumption and TTL are nice Speed. In intel chips you could see the transition at 8031 to 80C31, a CMOS with good speed. Now its CMOS everywhere. FET’s rule.

Leroy has created an amazing page that helps you make a choice. I like HCT but these days it appears ACT is better and affordable too.

Glue Logic IC Family Selection Guide

The Digital Electronic Interactive Tutors Gadgets, have a canvas view now. That means in iGoogle and Google Sites, you can set it to full size with a embedded schematic. The Normal view is also available unchanged.

Here is a Snapshot of a Live iGoogle Page showing a Digital Preset counter Gadget in Canvas view.

Other Gadgets are Logic Gates Tutor and Digital Timer more at dapj Gadgets – iGoogle Web Gadgets.

From Soldermans Basic Electronics

Multi-Instrument Digital Assistant – PIC16F84A

“It contains four instruments in one unit: logic probe, single channel logic state analyzer, frequency counter and serial code receiver.”

From Hobby Hound – DIY Electronics

The Engineer’s Assistant – Erik Grindheim

Serial code receiver The serial code receiver receives 42 bytes and displays them in both HEX and ASCII. The baud rate is selectale in 8 steps from 1200 to 115200.

Logic state analyzer This is a one-channel logic state analyzer. It fetches 300 single bit samples in a selectable rate from 25ms to 1┬ÁS (40 Hz to 1 MHz in 16 steps).

Frequency counter The frequency counter displays the frequency with up to 8 digits on the LCD. The refresh rate is 500ms.

Logic probe The low and high logic levels are displayed by LEDs which are OFF if the probe tip is floating.

Digital Circuits – delabs

These circuits are based on CD40xx Chips and other. You can use 74HCT or any other series that is available. use one family for a particular project. These were used nearly two decades ago. Use it for learning, glue logic or to interface your uC designs to external devices. Do not make only Logic based designs like some below. It would be better to use a uC, CPLD or FPGA if you are building a complex gadget Basic Digital Circuits

LM331 is a Voltage-to-Frequency Converters and 74C926 is a 4 Digit Counter. The first part of the circuit converts the amplified DC analog value from a shunt to pulses. The Second counts the pulses and Displays it on a Seven segment LED display.

Digital Timers, Counters and Clocks

  • Sequential Timer CD40xx
  • Sequential Timer 7217
  • Six Digit preset counter CD4518
  • Analog timer CD4541
  • Quad Presettable Timers
  • Digital Comparator 74HC85
  • Sequential Timer/counter 7217 with RAM
  • CD4060 and CD4020 based long duration timer.
  • Digital Timer Clock With Preset using Thumbwheel switch.
  • 1 Hz or 1 pps crystal clock using CD4060 and 32768 Hz Crystal

Mixed and Interface Circuits

  • Optical Proximity Switch
  • Profile Controller
  • Toaster timer 555
  • Quad analog input switch logic
  • Optical switch for water tap using LM555 and LM567
  • Diff input DS8830 to TTL convertor
  • Phase lock loop using 4046
  • Am hour meter for battery chargers or electroplating equipment. 74C926