Rainbow-electronics DS1972 Manual do Utilizador

1 of 23 REV: 083006 Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple re

DS1972: 1024-Bit EEPROM iButton 10 of 23 Figure 7-2. Memory Function Flow Chart (continued) AAhRead Scratch-Pad ?DS1972 sets ScratchpadByte Coun

DS1972: 1024-Bit EEPROM iButton 11 of 23 Figure 7-3. Memory Function Flow Chart (continued) * 1-Wire idle high for powerFrom Figure 72nd PartTo

DS1972: 1024-Bit EEPROM iButton 12 of 23 Figure 7-4. Memory Function Flow Chart (continued) F0hRead Memory ?Address< 90h ?YNBus Master TXTA1

DS1972: 1024-Bit EEPROM iButton 13 of 23 READ SCRATCHPAD COMMAND [AAh] The Read Scratchpad command allows verifying the target address and the i

DS1972: 1024-Bit EEPROM iButton 14 of 23 The idle state for the 1-Wire bus is high. If for any reason a transaction needs to be suspended, the

DS1972: 1024-Bit EEPROM iButton 15 of 23 SEARCH ROM [F0h] When a system is initially brought up, the bus master might not know the number of dev

DS1972: 1024-Bit EEPROM iButton 16 of 23 Figure 9-1. ROM Functions Flow Chart From Figure 92nd PartTo Memory FunctionsFlow Chart (Figure 7)Mast

DS1972: 1024-Bit EEPROM iButton 17 of 23 Figure 9-2. ROM Functions Flow Chart (continued) To Figure 9 1st Part From Figure 9 1st Part From Fig

DS1972: 1024-Bit EEPROM iButton 18 of 23 1-Wire SIGNALING The DS1972 requires strict protocols to ensure data integrity. The protocol consists o

DS1972: 1024-Bit EEPROM iButton 19 of 23 Master-to-Slave For a write-one time slot, the voltage on the data line must have crossed the VTH thre

DS1972: 1024-Bit EEPROM iButton 2 of 23 ABSOLUTE MAXIMUM RATINGS I/O Voltage to GND -0.5V, +6V I/O Sink Current 20mA Operating Temperature Range

DS1972: 1024-Bit EEPROM iButton 20 of 23 Slave-to-Master A read-data time slot begins like a write-one time slot. The voltage on the data line

DS1972: 1024-Bit EEPROM iButton 21 of 23 CRC GENERATION With the DS1972 there are two different types of CRCs. One CRC is an 8-bit type and is

DS1972: 1024-Bit EEPROM iButton 22 of 23 COMMAND-SPECIFIC 1-Wire COMMUNICATION PROTOCOL—LEGEND SYMBOL DESCRIPTION RST 1-Wire Reset Pulse genera

DS1972: 1024-Bit EEPROM iButton 23 of 23 MEMORY FUNCTION EXAMPLE Write to the first 8 bytes of memory page 1. Read the entire memory. With only

DS1972: 1024-Bit EEPROM iButton 3 of 23 PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS EEPROM Programming Current IPROG (Note 5, 19)

DS1972: 1024-Bit EEPROM iButton 4 of 23 DESCRIPTION The DS1972 combines 1024 bits of EEPROM, an 8-byte register/control page with up to 7 user

DS1972: 1024-Bit EEPROM iButton 5 of 23 Figure 2. Hierarchical Structure for 1-Wire Protocol Available Commands: DS1972 Command Level: Data

DS1972: 1024-Bit EEPROM iButton 6 of 23 Figure 5. Memory Map ADDRESS RANGE TYPE DESCRIPTION PROTECTION CODES 0000h to 001Fh R/(W) Data Mem

DS1972: 1024-Bit EEPROM iButton 7 of 23 The protection control registers determine how incoming data on a Write Scratchpad command is loaded in

DS1972: 1024-Bit EEPROM iButton 8 of 23 WRITING WITH VERIFICATION To write data to the DS1972, the scratchpad has to be used as intermediate sto

DS1972: 1024-Bit EEPROM iButton 9 of 23 Figure 7-1. Memory Function Flow Chart 0Fh Write Scratch- pad ? Bus Master TX TA1 (T7:T0), TA2 (T15:T8