Rainbow-electronics DS2422 Manual de usuario

1 of 48 REV: 111403Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of

DS242210 of 48Figure 5. 64-Bit Lasered ROMMSB LSB8-BitCRC Code48-Bit Serial Number8-Bit FamilyCode (41h)MSB LSB MSB LSB MSB LSBFigure 6. 1-Wire CRC Ge

DS242211 of 48MEMORYThe memory map of the DS2422 is shown in Figure 7. The 512 bytes general-purpose SRAM are located in pages0 through 15. The variou

DS242212 of 48ADDR b7 b6 b5 b4 b3 b2 b1 b0 Function Access*0228h First Byte Read— — Access W; —022Fh Eighth Byte Password0230h First Byte Full— — Acce

DS242213 of 48SAMPLE RATEThe content of the Sample Rate Register (addresses 0206h, 0207h) specifies the time elapse (in seconds if EHSS= 1, or minutes

DS242214 of 48Temperature Alarm Threshold ExamplesJ(°C)TALMhex decimal25.585h133-10.03Eh62SERIAL DATA INPUTIn addition to temperature, the DS2422 can

DS242215 of 48threshold registers that are associated to the serial data input. The registers for data alarm thresholds arelocated at address 020Ah (L

DS242216 of 48Register DetailsBIT DESCRIPTION BIT(S) DEFINITIONEDLA: Enable Data LowAlarmb0This bit controls whether, during a mission, the Data Low A

DS242217 of 48MISSION CONTROLThe DS2422 is set up for its operation by writing appropriate data to its special function registers, which are locatedin

DS242218 of 48ALARM STATUSThe fastest way to determine whether a programmed alarm threshold was exceeded during a mission is throughreading the Alarm

DS242219 of 48Register DetailsBIT DESCRIPTION BIT(S) DEFINITIONMIP: Mission In Progress b1If this bit reads 1 the device has been set up for a mission

DS24222 of 48ABSOLUTE MAXIMUM RATINGS*ALARM, PUMP_ONZ, SDATA, SCLK, CNVST, VPAD,I/O Voltage to GND-0.3V, +6VALARM, PUMP_ONZ, I/O Combined Sink Current

DS242220 of 48MISSION PROGRESS INDICATORDepending on settings in the Mission Control Register (address 0213h) the DS2422 will log temperature and/orse

DS242221 of 48Password Control RegisterADDR b7 b6 b5 b4 b3 b2 b1 b00227h EPWDuring a mission, there is only read access to this register.To enable pas

DS242222 of 48SERIAL DATA INTERFACE TUNINGThe serial interface consists of several signals that are intended to control external circuitry, such as an

DS242223 of 48lower address. Knowing the starting time point (Mission Time Stamp) and the interval between temperaturemeasurements one can reconstruct

DS242224 of 48Figure 10C. Two-Channel Logging, Different Resolution2E00h2FFFhTemperature25608-bit entriesExternal Data256016-bit entries(not used)Exte

DS242225 of 48If there is a risk of unauthorized access to the DS2422 or manipulation of data, one should define passwords forread access and full acc

DS242226 of 48WRITING WITH VERIFICATIONTo write data to the DS2422, the scratchpad has to be used as intermediate storage. First the master issues the

DS242227 of 48COPY SCRATCHPAD WITH PASSWORD [99h]This command is used to copy data from the scratchpad to the writable memory sections. After issuing

DS242228 of 48Figure 12-1. Memory/Control Function Flow ChartMaster TX Memory orControl Fkt. Command0FHWriteScratchpadMaster TXTA1 (T7:T0)Master TXTA2

DS242229 of 48Figure 12-2. Memory/Control Function Flow Chart99HCopy Scrpd.[w/PW]Master TXE/S ByteAuthorizationCode Match?DS2422 Copies ScratchpadData

DS24223 of 48PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITSI/O Pin, 1-Wire WriteStandard speed 60 120Overdrive speed, VPUP > 4.5V(Note 12)612Write-0

DS242230 of 48Figure 12-3. Memory/Control Function Flow Chart69HRead Mem.[w/PW]&CRCMaster TX64-Bits [Password]MasterTX Reset?CRC OK?Master RX &quo

DS242231 of 48Figure 12-4. Memory/Control Function Flow Chart96HClear Mem.[w/PW]55HForcedConversion?Master TX64-Bits [Password]NYNYMission inProgress?

DS242232 of 48Figure 12-5. Memory/Control Function Flow ChartNCCHStart Mission[w/PW]Master TX64-Bits [Password]MasterTX Reset?DS2422 InitiatesMission

DS242233 of 48CLEAR MEMORY WITH PASSWORD [96h]The Clear Memory with Password command is used to prepare the device for another mission. This command w

DS242234 of 48COMMANDINDICATION OFINTERFERENCEREMEDYWrite ScratchpadThe CRC16 at the end of thecommand flow reads FFFFh.Wait 0.5 seconds, 1-Wire reset

DS242235 of 48bus performs a reset. The DS2422 will communicate properly when used in conjunction with a DS2480B orDS2490 1-Wire driver and adapters t

DS242236 of 481-Wire ROM FUNCTION COMMANDSOnce the bus master has detected a presence, it can issue one of the eight ROM function commands that theDS2

DS242237 of 48command. The only way to set the RC bit is through successfully executing the Match ROM, Search ROM orOverdrive Match ROM command. Once

DS242238 of 48Figure 14-1. ROM Functions Flow ChartFrom Figure 142nd PartTo Memory FunctionsFlow Chart (Figure 12)Master TX Bit 0Master TX Bit 63Maste

DS242239 of 48Figure 14-2. ROM Functions Flow ChartFrom Figure 141st PartFrom Figure 141st PartTo Figure 14, 1st PartRC = 1 ?NYRC = 0 ; OD = 1Master T

DS24224 of 48Note 1:System RequirementNote 2:Maximum allowable pullup resistance is a function of the number of 1-Wire devices in the system and 1-Wir

DS242240 of 481-Wire SIGNALINGThe DS2422 requires strict protocols to ensure data integrity. The protocol consists of four types of signaling onone li

DS242241 of 48Master-to-SlaveFor a write-one time slot, the voltage on the data line must have crossed the VTH threshold before the write-onelow time

DS242242 of 48The sum of tRL + d (rise rime) on one side and the internal timing generator of the DS2422 on the other side definethe master sampling w

DS242243 of 48and decides whether to continue with an operation or to reread the portion of the data with the CRC error. With theinitial pass through

DS242244 of 48COMMAND-SPECIFIC 1-Wire COMMUNICATION PROTOCOL—LEGENDSYMBOL DESCRIPTIONRST 1-Wire Reset Pulse generated by masterPD 1-Wire Presence Puls

DS242245 of 48COPY SCRATCHPAD WITH PASSWORD (SUCCESS)RST PD Select CPS TA-E/S <PW/dummy> AA loopCOPY SCRATCHPAD WITH PASSWORD (INVALID TA-E/S OR

DS242246 of 48STOP MISSION WITH PASSWORDRST PD Select STP <PW/dummy> FFh FF loopTo verify success, read the General Status Register at address 0

DS242247 of 48STEP 2During the setup, the device needs to learn the following information:§ Time and Date§ Sample Rate§ Alarm Thresholds§ Alarm Co

DS242248 of 48MASTER MODE DATA (LSB FIRST) COMMENTSTX <7 FFh bytes> Write through the end of the scratchpadTX (Reset) Reset pulseRX (Presence) P

DS24225 of 48DS2422 Temperature Accuracy at 3V-2.500-2.000-1.500-1.000-0.5000.0000.5001.0001.5002.0002.5003.0003.500-40-30-20-1001020304050607080Tempe

DS24226 of 48PIN DESCRIPTIONPIN NAME FUNCTION1VPADOperating voltage of the serial interface pads CNVST, SCLK, SDATA. Used forlevel translation from th

DS24227 of 48under the control of SCLK. The DS2422 will activate its alarm output if the measured temperature or serial-inputdata reaches a user-progr

DS24228 of 48Figure 3. DS2422 Block DiagramAll circuitry is powered by the batteryunless otherwise specifiedInternalTimekeeping &Control Reg. &

DS24229 of 48Figure 4. Hierarchical Structure for 1-Wire Protocol1-Wire netOtherDevicesBUSMasterDS2422AvailableCommands:CommandLevel:Data FieldAffecte