The Microchip Technology Inc. 25AA/25LC/ products meet the specification contained in their particular Microchip Data Sheet. The 25LC is a 32K bit Serial Electrically Erasable PROM with memory accessed via a simple Serial Peripheral Interface (SPI&#;) View Datasheet. 25LC datasheet, 25LC pdf, 25LC data sheet, datasheet, data sheet, pdf, Microchip.

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Remember, a core part number usually represents hundreds datazheet actual part numbers due to different manufacturers, speeds, temperatures, package types and other chip characteristics. This way if our data comes out looking funny later on we can tell it isn’t just the serial port acting up:. The first step is setting datasjeet our pre-processor directives. Although not as fast, serial eeproms and nvrams find use in many products due to their small size and low cost. Note that we use the WREN opcode we defined at the beginning of the program.

The difficult part about SPI is that the standard is loose and each device implements it a datasgeet differently. You must be logged in to post a comment. Mainly two types of serial communication protocols are available: The CORE part number for each device is Care shall be taken at the B versions which have a different meaning! Unlike Flash devices, these memory parts can have individual bytes changed without the need to erase the entire part.

Next we send our bytes of data from our buffer array, one byte after another without pause. Serial Peripheral Interface SPI is a synchronous serial data protocol used by Microcontrollers for communicating with one or more peripheral devices quickly over short distances. Each chip has its own properties in terms of: This is accomplished by sending the required command, address and data serially one bit at a time over single pins instead of the multiple datasheef of a parallel part.


The device also offers various degerees of write protection and a hold 25lc3220, but we won’t be 25lc302 those in this tutorial. The NV stands for non-volatile. We add a line feed and a pause for readability. Both have there advantages and draw backs.

Data registers simply hold bytes.

A core part number 25ld320 a number which identifies a device regardless of the manufacturer. Most devices, regardless of the technology family, can be identified by their CORE part number.

Here we allocate the global variables we will be using later in the program. In absolute, SPI is faster and I use this protocol a lot in my applications.

25AA320/25LC320/25C320 PDF Datasheet浏览和下载

Memory Part 3 Posted on 31 Jan The FRAM is also a non-volatime memory component however it uses ferro-electric magnetic structure to store information. These parts appeared in the mid to early ‘s and most are still manufactured today. Status registers change their state based on various microcontroller conditions. Once they are programmed they cannot be changed.

B versions have something to do with the way data are arranged internally. Insert the AT25HP chip into the breadboard. A register is just a byte of microcontroller memory that can be read from or written to.

Their high storage capacity allows use in computer BIOS plus other memory intensive product applications. Registers generally serve three purposes, control, data and status.

These parts are always in plastic cases because the erasing of the part is done electrically without the need to expose the internal chip to ultraviolet light. My preference goes to SPI in spite of the highest number of pin required.

This approach allows you to more easily locate a device number, as many users do not know the manufacturer of the device in which they have interest.

Each has the manufacturers full part number printed on the device. A microcontroller normally has 40 or more pins since the input and output operations occur directly from the chip. CORE part numbers are easily discerned once you exclude any prefix or suffix characters.


Usually each bit in a control register effects a particular setting, such as speed or polarity.

Microcontrollers are usually found in products which perform a single function such as microwave ovens, computer printers, automatic sprinkler controllers, etc.

Once you have your SPI Control Register set correctly you just need to figure out how long you need to pause between instructions and you are ready to go. The images on the bottom right are close-up views of the first three eprom packages. Powered by WordPress and plainscape theme. Since the individual listing of every part number from every manufacturer creates a prohibitively large list, we list all supported manufacturers in a separate table with core part numbers arranged by technology family and pin count where applicable.

Instructions are sent as 8 bit operational codes opcodes and are shifted in on the rising edge of the data clock.

When the address increments to we turn it back to 0 because we have only filled addresses in the EEPROM with data:. Opcodes are control commands:. It’s memory is organized as pages of bytes each.


We send the 16 bit address to begin writing at in two bytes, Most Significant Bit first. The example below describes how to determine a typical core part number. It can also be used for communication between two microcontrollers. Connect 5V power and ground dtasheet the breadboard to 5V power and ground from the microcontroller.