Programming 24LC256 I2C EEPROM

interfacing eeprom 24LC256

In many microcontroller projects, you need some non-volatile memory – which preserves data even when power is off. A most popular type of such memory is Flash or EEPROM. Many MCUs like AVR or PIC already have some EEPROM inside chip that may suit your needs. But in many cases, it is not included, and you may need to connect it externally. EEPROMs with I2C interface is very common in such situation as they don’t need lots of I/Os (only two wires). If you decided to add an EEPROM chip into your project, check out the handy guide on how it works written by Jesus Echavarria. As an example, he took 24LC256 EEPROM which capacity is 32K x 8 bytes. The chip works in pretty wide voltage range – between 1.7V and 5.5V which is great either for 3.3V or 5V setups. He covers all the basic things you need to consider, including selecting proper chip slave address in I2C line. Then performing reading and writing EEPROM data in byte and page modes. This guide might serve as a nice… Continue reading

Temperature sensor and storage for embedded projects

Temperature sensor and storage for embedded projects

I2C interface allows connecting multiple devices using two wires. This interface is very popular in sensors, memory chips and IO expanders. R-B designed compact breakout board where he placed MCP9802 temperature sensor and 24LC512 EEPROM. Module is convenient to use as temperature sensor with ability to log values in to near by memory. So if you decide to unplug sensor – history of data goes with you. 512Kbit EEPROM gives enough space for storing data. Digital temperature sensor is capable of measuring temperatures from -55ºC to 125ºC. Prototyping board is designed so it could be easily plugged in to prototyping breadboard. Continue reading

AVR at a glance

Any AVR microcontroller is an 8-bit computer in a chip designed and manufactured by ATMEL Corporation. It has some RAM and ROM (Flash) as well. There is also an EEPROM memory. Including AVR core CPU all these are more than enough to say that it is a small computer where you can execute programs stored in Flash memory, run them while operating data in SRAM and storing some constant values in EEPROM. Comparing to the real computer that sits on your table you can say that AVR core is a CPU like AMD or Pentium. Flash memory would be your hard drive where programs are stored, RAM is RAM nothing to add there. EEPROM probably can be compared to some media device like CDRW. Anyway, this is only similitude in a different scale. AVR microcontrollers aren’t limited with core CPU and memory. The main thing what makes them valuable (and any other type of microcontroller) – they are rich in peripherals inside the chip. In most cases, you will find USART, I2C, SPI, ADC, Timers/Counters, and a bunch of I/O… Continue reading

Tiny GSM Alarm System – The Smart and Portable Sensor Trigger

Did anyone here ever get in touch with the GSM call alarm or GSM SMS alarm before? If you did, then the Tiny GSM alarm system is going to be the masterpiece combination of the call alarm and SMS alarm! The main purpose of the tiny GSM alarm system is a device, which is can be used to operate standalone or as a module for existing alarm system. The tiny GSM alarm system is much more advanced than the previous, as it’s not only can arm or disarm the system with “enable” pin, but you can do the same task by simply calling from your own phone! Sounds like a cool add-on, isn’t it? Well, the tiny GSM alarm system is built on a very popular microcontroller, the PIC16F84A. In this case, you don’t have to bother with external EEPROM memory for SMS storage, as you have the option to use phone’s SIM SMS storage and phonebook memory for the storage task! Well, the GSM phone that is best compatible with the device is Siemens M35i. To be honest, it’s… Continue reading

Scrolling Text on Oscilloscope – Even the Elementary Students Can Do It Too!

Oscilloscopes are one of the most familiar electronic components, which most of the home hobbyists might have got in touch with it, at least once in their life! Ok, maybe you’ve been done multiple experiments with Oscilloscope before, but have you ever try to use it for scrolling text? Yep, even though it’s not a new method, however, it would give you a several “surprises” that you’re not expected at all! So, it’s a very simple project that based on a PIC micro PIC16F628A. Why we said it’s a very simple project? It’s because it only have one component plus the battery! Basically, the main purpose of the circuit is to show a scrolling text on oscilloscope. In this case, those characters, which are going to be displayed can be stored by user in EEPROM. The first EEPROM location with 0xFF value is considered as the end of text. The last EEPROM location with 0x7F is containing the scrolling speed in 20mS steps. Normally, a jumper would be placed between the pins Vdd and Vpp, after programming the micro via… Continue reading

The PIC 16F877-based USB Interface

Guys, PIC USB Interface is not longer a fresh stuff, as many of you have been created this project before, maybe not once, but twice or more… However, each of the PIC USB Interface is having its own specialty, like this PIC 16F877 microcontroller. Well, it’s a simple design, which is using the PIC16F877 microcontroller and the FTDI FT245 USB FIFO device as the main parts. Basically, it has been designed using a single-sided PCB with only one surface mount device. Since it used the FTDI FT245BM FIFO device in the project, the part is able to handle all the details of communicating via the USB bus. By only a simple 1Kbit serial EEPROM, it holds most of the USB configuration information. After you’ve assembling the PCB, you must doing the inspection for solder shorts. You can remove the PIC microcontroller and plug in the PCB + USB device + EEPROM into a USB hub on your PC! Keep in mind that the release of the FTDI Common Driver Model (CDM) driver setup is very easy. Well, you just had… Continue reading