Multibyte Write. The Multibyte Write mode can be started from any address in the memory. The master sends from one up to 4 bytes of data, which are each acknowledged by the mem- ory. The transfer is terminated by the master gen- erating a STOP condition.
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The device is organized as a single block of x 8-bit memory with a 2-wire serial interface. The device has a page write capability for up to 16 bytes of data and has fast write cycle times of only 1 ms for both byte and page writes. Vss I2C is a trademark of Philips Corporation. DSG-page 1 24C02C 1. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational listings of this specification is not implied.
Exposure to maximum rating conditions for extended periods may affect device reliability. As a transmitter, the device must provide an internal minimum delay time to bridge the undefined region minimum ns of the falling edge of SCL to avoid unintended generation of Start or Stop conditions. This eliminates the need for a TI specification for standard operation. This parameter is not tested but ensured by characterization. DSG-page 3 24C02C 2. A device that sends data onto the bus is defined as transmitter, and a device receiving data as receiver.
The bus has to be controlled by a master device which generates the Serial Clock SCL , controls the bus access, and generates the Start and Stop conditions, while the 24C02C works as slave. Both master and slave can operate as transmitter or receiver but the master device determines which mode is activated.
This input is used to synchronize the data transfer from and to the device. The chip is selected if the compare is true. Up to eight 24C02C devices may be connected to the same bus by using different Chip Select bit combinations. If tied to Vcc, the hardware write protection is enabled. If the WP pin is tied to Vss the hardware write protection is disabled. Changes in the data line while the clock line is high will be interpreted as a Start or Stop condition.
Accordingly, the following bus conditions have been defined Figure The data on the line must be changed during the low period of the clock signal. There is one bit of data per clock pulse. Each data transfer is initiated with a Start condition and terminated with a Stop condition. The number of the data bytes transferred between the Start and Stop conditions is determined by the master device and is theoretically unlimited, although only the last sixteen will be stored when doing a write operation.
When an overwrite does occur it will replace data in a first-in firstout fashion. The master device must generate an extra clock pulse which is associated with this Acknowledge bit. Note: The 24C02C does not generate any Acknowledge bits if an internal programming cycle is in progress.
All commands must be preceded by a Start condition. All operations must be ended with a Stop condition. The device that acknowledges has to pull down the SDA line during the Acknowledge clock pulse in such a way that the SDA line is stable low during the high period of the acknowledge related clock pulse.
Of course, setup and hold times must be taken into account. A master must signal an end of data to the slave by not generating an Acknowledge bit on the last byte that has been clocked out of the slave. In this case, the slave must leave the data line high to enable the master to generate the Stop condition Figure Transmitter must release the SDA line at this point allowing the Receiver to pull the SDA line low to acknowledge the previous eight bits of data.
DSG-page 5 24C02C 5. The Chip Select bits allow the use of up to eight 24C02C devices on the same bus and are used to select which device is accessed. The Chip Select bits in the control byte must correspond to the logic levels on the corresponding A2, A1 and A0 pins for the device to respond. These bits are in effect the three Most Significant bits of the word address.
The last bit of the control byte defines the operation to be performed. In this case, software can use A0 of the control byte as address bit A8, A1 as address bit A9, and A2 as address bit A It is not possible to write or read across device boundaries. The device will acknowledge this control byte during the ninth clock pulse. The next byte transmitted by the master is the word address and will be written into the Address Pointer of the 24C02C.
After receiving another Acknowledge signal from the 24C02C the master device will transmit the data word to be written into the addressed memory location. The 24C02C acknowledges again and the master generates a Stop condition. This initiates the internal write cycle, and during this time the 24C02C will not generate Acknowledge signals Figure If an attempt is made to write to the protected portion of the array when the hardware write protection has been enabled, the device will acknowledge the command but no data will be written.
The write cycle time must be observed even if the write protection is enabled. As with the byte write operation, once the Stop condition is received an internal write cycle will begin Figure If an attempt is made to write to the protected portion of the array when the hardware write protection has been enabled, the device will acknowledge the command, but no data will be written.
Note: Page write operations are limited to writing bytes within a single physical page, regardless of the number of bytes actually being written. If a Page Write command attempts to write across a physical page boundary, the result is that the data wraps around to the beginning of the current page overwriting data previously stored there , instead of being written to the next page as might be expected. It is therefore necessary for the application software to prevent page write operations that would attempt to cross a page boundary.
But instead of generating a Stop condition, the master transmits up to 15 additional data bytes to the 24C02C which are temporarily stored in the on-chip page buffer and will be written into the memory after the master has transmitted a Stop condition. After the receipt of each word, the four lower order Address Pointer bits are internally incremented by one.
The higher order four bits of the word address remains constant. If the master should transmit more than 16 bytes prior to generating the Stop condition, the address counter will roll over and the previously received data will be overwritten. DSG-page 7 24C02C 7. Once the Stop condition for a Write command has been issued from the master, the device initiates the internally timed write cycle. ACK polling can be initiated immediately. If the device is still busy with the write cycle, then no ACK will be returned.
If no ACK is returned, then the Start bit and control byte must be re-sent. If the cycle is complete, then the device will return the ACK and the master can then proceed with the next Read or Write command. See Figure for flow diagram.
There are three basic types of read operations: current address read, random read, and sequential read. The master will not acknowledge the transfer, but does generate a Stop condition and the 24C02C discontinues transmission Figure To perform this type of read operation, first the word address must be set. This is done by sending the word address to the 24C02C as part of a write operation. After the word address is sent, the master generates a Start condition following the acknowledge.
This terminates the write operation, but not before the internal Address Pointer is set. The 24C02C will then issue an acknowledge and transmits the eight bit data word. The master will not acknowledge the transfer but does generate a Stop condition and the 24C02C discontinues transmission Figure After this command, the internal address counter will point to the address location following the one that was just read. Yes Next Operation No 8. This directs the 24C02C to transmit the next sequentially addressed 8-bit word Figure To provide sequential reads, the 24C02C contains an internal Address Pointer which is incremented by one at the completion of each operation.
This Address Pointer allows the entire memory contents to be serially read during one operation. The internal Address Pointer will automatically roll over from address FF to address DSG-page 9 24C02C 9. In the event the full Microchip part number cannot be marked on one line, it will be carried over to the next line, thus limiting the number of available characters for customer-specific information.
Note: Note: Please visit www. Pin 1 visual index feature may vary, but must be located with the hatched area. Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed. BSC: Basic Dimension. Theoretically exact value shown without tolerances. Pin 1 visual index feature may vary, but must be located within the hatched area. Mold flash or protrusions shall not exceed 0.
REF: Reference Dimension, usually without tolerance, for information purposes only. Package may have one or more exposed tie bars at ends. Package is saw singulated. This web site is used as a means to make files and information easily available to customers. Local sales offices are also available to help customers. A listing of sales offices and locations is included in the back of this document.
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Device: 24C02C Questions: 1.
24C02 Datasheet, PDF, Circuit Diagram, Application Notes