Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
SMS1242S Datasheet(PDF) 7 Page - Summit Microelectronics, Inc. |
|
SMS1242S Datasheet(HTML) 7 Page - Summit Microelectronics, Inc. |
7 / 11 page 7 2038 2.0 6/8/00 SMS1242 SUMMIT MICROELECTRONICS, Inc. MEMORY OPERATION The SMS1242 memory is configured as a 2k × 8 array. Data is read and written via an industry standard two-wire interface. The bus was designed for two-way, two-line serial communication between different integrated cir- cuits. The two lines are a serial data line (SDA) and a serial clock line (SCL). The SDA line must be connected to a positive supply by a pull-up resistor located somewhere on the bus Input Data Protocol The protocol defines any device that sends data onto the bus as a “transmitter” and any device that receives data as a “receiver.” The device controlling data transmission is called the “master” and the controlled device is called the “slave.” In all cases the SMS1242 will be a “slave” device since it never initiates a data transfer. One data bit is transferred during each clock pulse. The data on the SDA line must remain stable during clock high time, because changes on the data line while SCL is high will be interpreted as start or stop condition. START and STOP Conditions When both the data and clock lines are high the bus is said to be not busy. A high-to-low transition on the data line while the clock is high is defined as the “START” condition. A low-to-high transition on the data line while the clock is high is defined as the “STOP” condition. Acknowledge (ACK) Acknowledge is a software convention used to indicate successful data transfers. The transmitting device, either the master or the slave, will release the bus after transmit- ting eight bits. During the ninth clock cycle the receiver will pull the SDA line low to ACKnowledge that it received the eight bits of data. The SMS1242 will respond with an ACKnowledge after recognition of a START condition and its slave address byte. If both the device and a write operation are selected, the SMS1242 will respond with an ACKnowledge after the receipt of each subsequent 8-bit word. In the READ mode the SMS1242 transmits eight bits of data, then releases the SDA line, and monitors the line for an ACKnowledge signal. If an ACKnowledge is detected and no STOP condition is generated by the master, the SMS1242 will continue to transmit data. If an ACKnowledge is not detected the SMS1242 will terminate further data trans- missions and await a STOP condition before returning to the standby power mode. Device Addressing Following a start condition the master must output the address of the slave it is accessing. The most significant four bits of the slave address are the device type identifier. For the SMS1242 this is fixed as 1010BIN. The next three bits are the Most Significant Bits of the data address. They are supplied for write operations, and are "don't care" for read operations. Read/Write Bit The last bit of the data stream defines the operation to be performed. A “1” indicates a read operation; and a “0,” a write operation. 2038 Table02 2.0 r e i f i t n e d I e c i v e Ds t i B s s e r d d A S MW / R 10 10 0 1 A9 A8 A0 / 1 WRITE OPERATIONS The SMS1242 allows two types of write operations: byte write and page write. A byte write operation writes a single byte during the nonvolatile write period (tWR). The page write operation allows up to 16 bytes in the same page to be written during tWR. Byte Write Upon receipt of the word address the SMS1242 responds with an ACKnowledge. After receiving the next byte of data it responds with another ACKnowledge. The master then terminates the transfer by generating a STOP condi- tion, at which time the SMS1242 begins the internal write cycle. While the internal write cycle is in progress the SMS1242 inputs are disabled and the device will not respond to any requests from the master. Page Write The SMS1242 is capable of a 16-byte page write opera- tion. It is initiated in the same manner as the byte-write operation, but instead of terminating the write cycle after the first data word the master can transmit up to 15 more bytes of data. After the receipt of each byte the SMS1242 will respond with an ACKnowledge. The SMS1242 automatically increments the address for subsequent data words. After the receipt of each word, the low order address bits are internally incremented by one. The high order bits of the address byte remain constant. |
Número de pieza similar - SMS1242S |
|
Descripción similar - SMS1242S |
|
|
Enlace URL |
Política de Privacidad |
ALLDATASHEET.ES |
¿ALLDATASHEET es útil para Ud.? [ DONATE ] |
Todo acerca de Alldatasheet | Publicidad | Contáctenos | Política de Privacidad | Intercambio de Enlaces | Lista de Fabricantes All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |