Rainbow-electronics DS1904 User Manual

1 of 12 022400PRELIMINARYDS1904RTC iButtonwww.iButton.comSPECIAL FEATURES Real-Time Clock/calendar in binary format Uses the same binary time/date

DS190410 of 12READ/WRITE TIMING DIAGRAM Figure 9Write-one Time Slot15µs(OD: 2µs)60µs(OD: 6µs)DS1904SamplingVPULLUPVPULLUP MINVIH MINVIL MAX0VtSLOTtREC

DS190411 of 12PHYSICAL SPECIFICATIONSize See mechanical drawingWeight 3.3 gramsHumidity 90% RH at 50°CAltitude 10000 feetExpected Service Life 10 y

DS190412 of 12NOTES:1. All voltages are referenced to ground.2. VPUP = external pull-up voltage.3. Input load is to ground.4. Read data setup time

DS19042 of 12hazards such as dirt, moisture, and shock. Accessories permit the DS1904 to be mounted on almost anysurface including printed circuit boa

DS19043 of 12HIERARCHICAL STRUCTURE FOR 1-WIRE PROTOCOL Figure 2DS1904CommandLevel AvailableCommands Data FieldsAffected 1-Wire BusOtherDevicesBusM

DS19044 of 12TIMEKEEPINGA 32.768 kHz crystal oscillator is used as the time base for the real-time clock counter. The oscillator canbe turned on or of

DS19045 of 12CLOCK FUNCTION COMMAND FLOW CHART Figure 5Master TX ControlFunction Command66HRead Clock?YNBus MasterTX Reset?NYNBus MasterTX Reset?DS190

DS19046 of 12READ CLOCK [66h]The read clock command is used to read the device control byte and the contents of the real-time clockcounter. After havi

DS19047 of 12The idle state for the 1-Wire bus is high. If for any reason a transaction needs to be suspended, the busMUST be left in the idle state i

DS19048 of 12ROM FUNCTIONS FLOW CHART Figure 7F0HSearch ROMCommand?DS1904 TX Bit 0DS1904 TX Bit 0Master TX Bit 0Bit 0Match ?DS1904 TX Bit 1DS1904 TX

DS19049 of 12Skip ROM [CCh]This command can save time in a single drop bus system by allowing the bus master to access the clockfunctions without prov