Serial EEPROM Serial EEPROM (93C46 / 93CS46) Routines Don't like reading docs, why not just? Contents • • • • • • Serial EEPROMs are small Electronically Erasable Programmable Read Only Memory chips. These devices are usually used to store user configurable parameters and device serial numbers. They use a serial bus interface, which allows them to be packaged in inexpensive 8 pin packages. To you, the 8051 system designer, these little chips offer a nifty way to store a small amount of data in non-volatile memory, using only a few of the port pins, and without raising the system's cost much. They are usually specified to retain the data for 10 years and to endure 100,000 write operations before failure.

They only require a 5 volt power supply (some 3V only versions exist too). Because these chips use a serial interface, they can not be read quickly enough to serve as conventional memory. In addition, a considerable length of time (milliseconds) is required to perform a write operation. They typically hold less than 1024 bytes of memory. However, they usually cost less than $1.00 (US) for single piece quantities, making them pretty desirable memory devices for storing configuration parameters or other bits of information that should be retained when the power is lost. There are several types of Serial EEPROMs, but most of them fall into either a 2-wire or 3-wire interface category.

Usually, the 3-wire devices require an addition wire (beyond the 3 for data transfer) for each chip to be used. The 2-wire interface, called I 2C or IIC or 'I squared C' uses only two wires, regardless of how many chips are attached. I 2C is a trademard of. The three wire interfaces include SPI and Microwire, which is a trademark of.

Metodicheskie razrabotki po sensorike dlya detej 2 3 let. As the pressure on engineers to make products smaller has grown, semiconductor manufacturers have introduced several new interfaces, usually aimed at lower a product's size and cost. And undoubtedly many more will appear in the future. As a practical matter, the code offered below only works with the Microwire 3 Wire interface, and is specifically intended to work with the 93C46, which is a standard part available from a variety of distributors. The code below works with the 93CS46 Serial EEPROM.

In-circuit serial EEPROM programmer. Special made for in-circuit serial EEPROM programming. Very useful to make car electronic programming faster and easy without soldering. In most cases short microcontroller quartz resonator or short MPU reset pin to GND.

It can be used without much difficulty with a 93C46, by avoiding calls to the routines that manipulate the extended features of the 93CS46. Manufacturers has data sheets on-line for most of their EEPROM and microcontroller products. They have also added example 8051 code similar to the code below, as well as for I 2C parts they offer. Has lots of data sheets on-line. I used their to write the code. Their literature number is 800-272-9959. Or at least is was some time ago when I put their sticker on my phone.

Schematic

Now has data sheets on-line for most of their products. They offer the 93C46, as well as a variety of other EEPROMs. Made the chips I used when I wrote this code. I used the National datasheet to write the code, but the SGS Thompson parts worked flawlessly. They offer quite a few different types of serial eeproms, including of course the 93CS46 and 93C46. Offers 2-Wire interface and SPI interface serial EEPROMs, but apparantly nothing which will work with the code below.