Tag Archives: EEPROM

DS28EC20, A Serial 1-Wire 20Kb EEPROM

The American manufacturer of analog and mixed-signal integrated circuits, Maxim Integrated, has developed a new serial EEPROM memory that operates from single-contact 1-wire interface.

The DS28EC20 is a 20480-bit, 1-Wire® EEPROM organized as 80 memory pages of 256 bits each. An additional page is set aside for control functions. Data is written to a 32-byte scratchpad, verified, and then copied to the EEPROM memory.

The 1-Wire is a device communications bus system that provides low-speed data, signaling, and power over a single conductor. This technology uses only two wires; data and ground. It is similar in concept to I²C, but with lower data rates and longer range. It is typically used to communicate with small inexpensive devices such as digital thermometers and weather instruments.

DS28EC20 features:
  • 20480 Bits of Nonvolatile (NV) EEPROM Partitioned into Eighty 256-Bit Pages
  • Individual 8-Page Groups of Memory Pages (Blocks) can be Permanently Write Protected or Put in OTP EPROM-Emulation Mode (“Write to 0”)
  • Read and Write Access Highly Backward-Compatible to Legacy Devices (e.g., DS2433)
  • 256-Bit Scratchpad with Strict Read/Write Protocols Ensures Integrity of Data Transfer
  • 200k Write/Erase Cycle Endurance at +25°C
  • Unique Factory-Programmed 64-Bit Registration Number Ensures Error-Free Device Selection and Absolute Part Identity
  • Switchpoint Hysteresis and Filtering to Optimize Performance in the Presence of Noise
  • Communicates to Host at 15.4kbps or 90kbps Using 1-Wire Protocol
  • Low-Cost TO-92 Package
  • Operating Range: 5V ±5%, -40°C to +85°C
  • IEC 1000-4-2 Level 4 ESD Protection (8kV Contact, 15kV Air, Typical) for I/O Pin

Blocks of eight memory pages can be write-protected or put in EPROM-Emulation mode, where bits can only be changed from a 1 to a 0 state. The life-expectancy of the DS28EC20 is specified at more that 200 k erase/write cycles at 25 °C. The I/O pin has IEC 1000-4-2 Level 4 ESD protections (8 kV contact, 15 kV air).

Applications that can use the DS28EC20:
  • Card/Module Identification in Rack-Based Systems
  • Device Authentication
  • IEEE 1451.4 Sensors
  • Ink and Toner Cartridge ID
  • Medical and Industrial Sensor Identification/Calibration
  • PCB Identification
  • Smart Cable

Ordering DS28EC20 is available for about $1.7 per chip through Maxim website. You can also get design resources and technical documents of the chip.

Analog front-end IC linearizes sensors


Susan Nordyk @ edn.com discuss about LTC2986 which is able to digitize and linearize a combination of temperature sensors in Celsius or Fahrenheit degrees.

A 10-channel temperature-measurement IC, the LTC2986 from Linear Technology directly digitizes any combination of thermocouples, RTDs, thermistors, and external diodes with 0.1°C accuracy and 0.001°C resolution. The analog front-end device combines three 24-bit delta-sigma ADCs with all the necessary excitation and control circuits for each sensor. On-chip EEPROM stores user configuration data and custom sensor coefficients, eliminating IC or sensor programming by a host processor.

The LTC2986 measures absolute microvolt-level signals from thermocouples and ratiometric resistance from RTDs and thermistors. It performs linearization and outputs the results in °C or °F. With 10 analog inputs, the LTC2986 accommodates up to 9 thermocouples, 4 RTDs, 4 thermistors, and/or 10 diodes, with support for Type B, E, J, K, N, S, R, and T thermocouples; 2-wire, 3-wire, and 4-wire RTDs; and 2.25-kΩ to 30-kΩ thermistors.

Analog front-end IC linearizes sensors – [Link]

USB to UART Converter with GPIO – MCP220


The Module is based on The MCP2200, which is a USB-to-UART serial converter which enables USB connectivity in application that have a UART interface. The device reduces external components by integrating the USB termination resistors. The MCP2200 also has 256-bytes of integrated user EEPROM. The MCP2200 has eight general purpose input / output pins. Four of the pins have alternate functions to indicate USB and communication status.


  • Supply 3- 5V DC
  • On Board TX & RX LED
  • USB activity LED outputs (TxLED and RxLED)
  • Mini USB Interface
  • 6 + 6 PIN Header Connector for I/O and RX-TX Signals
  • UART signal polarity option General Purpose Input/output (GPIO) Pins
  • Eight (8) general purpose I/O pins
  • Supports Full-Speed USB (12 Mb/s)

USB to UART Converter with GPIO – MCP220 – [Link]

PIC16F628A Programmable Digital Timer


Raj Bhatt shared another project with us. This time is a programmable digital timer with relay switch based on PIC16F628A.

Programmable relays find use in numerous automation applications such as automatic street light control, watering and pump control, HVAC, home automation, power plants automation in industries, etc. This article describes how to build a fully functional, one-channel programmable relay switch using the PIC16F628A microcontroller. It allows you to set both ON and OFF time. The maximum time interval that you can set for on and off operations is 99 hours and 59 minutes. Another interesting feature of this project is it offers cyclic option, which means you can choose to run it in a continuous loop of ON and OFF cycles. The device can be programmed through 4 push switches. The programming menu and device status are displayed on a 16×2 character LCD. The timing resolution of this relay timer is 1 minute. The timer also saves the user inputs to its internal EEPROM so that it can retain these values after any power supply interrupt.

PIC16F628A Programmable Digital Timer – [Link]


Generation of Sound Using Microcontroller

This project illustrates the use of a microcontroller(MCU) to generate different types of sound. The device uses SST89E54RDA-40-C-PIEMCU, an 8-bit 8051-compatible MCU with embedded SuperFlash memory.The device comes with 24/40KByte of on-chip flash EEPROM program memory which is partitioned into two independent program memory blocks. The primary block 0 occupies 16/32KByte of internal program memory space while the secondary block 1 occupies 8KByte of internal program memory space.

Sound is a function of frequency. This concept has been used to generate sound from the microcontroller. Varying the frequency can produce different types of sounds especially with the use of timer 1 of the MCU to produce different frequencies. Timer is used to produce exact delays and by toggling the output pin, it will generate the desired frequencies. These frequencies are then fed to pin 0 of port 1 which is connected to the speaker. By combining frequencies of different values, different tones will be produced.

The circuit is a basic sound generator that has wide applications such as used in cars that produce sound while reversing. In addition, it supports electronic piano to generate different tones, or in electronic toys to generate sounds. Thus, this device is an effective sound generator that produces an audible sound as preferred by the user.

Generation of Sound Using Microcontroller – [Link]

Delay using 8051 Timer

The major component of this circuit is Microchip’s SST89E54RDA-40-C-PIE, which is a pin-for-pin compatible with typical 8051 microcontroller devices. It has a built-in timer used to produce accurate time delay. The light emitting diode (LED) is connected through the 330Ω resistor to indicate the time delay. The blinking LED switches ON for 1ms and switches OFF for 1ms that indicates toggling from LOW to HIGH and HIGH to LOW. Output PIN P2.2 can be connected to an oscilloscope to generate a square wave.

SST89E58RDA-40-C-PIE comes with 72 Kbyte of on-chip flash EEPROM program memory that is partitioned into 2 independent program memory blocks. The primary Block 0 occupies 64 Kbyte of internal program memory space and the secondary Block 1 occupies 8 Kbyte of internal program memory space. The 8-Kbyte secondary blocks can be mapped to the lowest location of the 64 Kbyte address space; it can also be hidden from the program counter and used as an independent EEPROM-like data memory. In addition to the 72 Kbyte of EEPROM program memory on-chip and 1024 x8 bits of on-chip RAM, the devices can address up to 64 Kbyte of external program memory and up to 64 Kbyte of external RAM.

This design integrating Microchip’s SST89E54RDA-40-C-PIE would be used if high-accuracy, precision and timing resolution of timed events are required to activate or deactivate control outputs based on programmed time intervals. Time delay applications include pump control, food processing, and packaging control where precise ON/OFF control is necessary.

Delay using 8051 Timer – [Link]



EEPROM Add-On Board offers an easy way to interface a standard 24Cxx type I2C EEPROM to your project.


  • 5 VDC supply sourced through the interfacing Box Header connector
  • Jumper selectable address option available
  • Four mounting holes 3.2 mm each
  • PCB dimensions 36 mm x 32 mm

EEPROM Module – [Link]