전자부품 데이터시트 검색엔진 |
|
DS1855 데이터시트(PDF) 6 Page - Dallas Semiconductor |
|
DS1855 데이터시트(HTML) 6 Page - Dallas Semiconductor |
6 / 20 page DS1855 6 of 20 2-WIRE OPERATION Clock and Data Transitions The SDA pin is normally pulled high with an external resistor or device. Data on the SDA pin may only change during SCL low time periods. Data changes during SCL high periods will indicate a START or STOP conditions depending on the conditions discussed below. Refer to the timing diagram in Figure 2 for further details. START Condition A high-to-low transition of SDA with SCL high is a START condition that must precede any other command. Refer to the timing diagram in Figure 2 for further details. STOP Condition A low-to-high transition of SDA with SCL high is a STOP condition. After a read sequence, the stop command places the DS1855 into a low-power mode. Refer to the timing diagram in Figure 2 for further details. Acknowledge All address and data bytes are transmitted via a serial protocol. The DS1855 pulls the SDA line low during the ninth clock pulse to acknowledge that it has received each word. Standby Mode The DS1855 features a low-power mode that is automatically enabled after power-on, after a STOP command, and after the completion of all internal operations. 2-Wire Interface Reset After any interruption in protocol, power loss, or system reset, the following steps reset the DS1855: 1. Clock up to nine cycles. 2. Look for SDA high in each cycle while SCL is high. 3. Create a START condition while SDA is high. Device Addressing The DS1855 must receive an 8-bit device address word following a START condition to enable a specific device for a read or write operation. The address word is clocked into the DS1855 MSB to LSB. The address word consists of Ah (1010) followed by A2, A1, and A0 then the read/write (R/W) bit. If the R/W bit is high, a read operation is initiated. If the R/W is low, a write operation is initiated. For a device to become active, the values of A2, A1, and A0 must be the same as the hard-wired address pins on the DS1855. Upon a match of written and hard-wired addresses, the DS1855 will output a zero for one clock cycle as an acknowledge. If the address does not match, the DS1855 returns to a low-power mode. Write Operations After receiving a matching address byte with the R/W bit set low, the device goes into the write mode of operation. The master must transmit an 8-bit EEPROM memory address to the device to define the address where the data is to be written. After the reception of this byte, the DS1855 will transmit a zero for one clock cycle to acknowledge the receipt of the address. The master must then transmit an 8-bit data word to be written into this address. The DS1855 will again transmit a zero for one clock cycle to acknowledge the receipt of the data. At this point, the master must terminate the write operation with a STOP condition. The DS1855 then enters an internally timed write process Tw to the EEPROM memory. All inputs are disabled during this byte write cycle. |
유사한 부품 번호 - DS1855 |
|
유사한 설명 - DS1855 |
|
|
링크 URL |
개인정보취급방침 |
ALLDATASHEET.CO.KR |
ALLDATASHEET 가 귀하에 도움이 되셨나요? [ DONATE ] |
Alldatasheet는? | 광고문의 | 운영자에게 연락하기 | 개인정보취급방침 | 링크교환 | 제조사별 검색 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 |