Rainbow-electronics DS1721 Manual de usuario

1 of 16 111999FEATURES Temperature measurements require noexternal components with ±1°C accuracy Measures temperatures from -55°C to+125°C; Fahren

DS172110 of 16SLAVE ADDRESSA control byte is the 1st byte received following the START condition from the master device. Thecontrol byte consists of a

DS172111 of 16Stop Convert T [22h]This command stops temperature conversion. No further data is required. This command may be used tohalt a DS1721 in

DS172112 of 16SAMPLE COMMAND SEQUENCE Table 5Example: After power-up, initiates a temperature conversion, bus master reads temperatureBUS MASTERMODEDS

DS172113 of 16SAMPLE COMMAND SEQUENCE Table 6Example: Bus master programs the DS1721 for 11-bit conversions in the continuous mode with an activelow s

DS172114 of 16ABSOLUTE MAXIMUM RATINGS*Voltage on VDD, Relative to Ground -0.3V to +7.0VVoltage on any other pin, Related to Ground -0.3V to +7.0VOper

DS172115 of 16DC ELECTRICAL CHARACTERISTICS:DIGITAL THERMOMETER (-55°C to +125°C; 2.7V ≤ VDD ≤ 5.5V)PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS NOTES

DS172116 of 16NOTES:1. All voltages are referenced to ground.2. I/O pins of fast mode devices must not obstruct the SDA and SCL lines if VDD is swit

DS17212 of 16DETAILED PIN DESCRIPTION Table 1PIN SYMBOL DESCRIPTION1SDAData input/output pin. For 2-wire serial communication port.2SCLClock input/out

DS17213 of 16temperature falls below TL. Thus, any hysteresis can be realized for fan control without externalcomponents.Digital data is written to/re

DS17214 of 16OPERATION-Measuring TemperatureThe core of DS1721 functionality is its direct-to-digital temperature sensor. The DS1721 measurestemperatu

DS17215 of 16The active state for the totem-pole output is programmable by the user. The power-up default of theDS1721 has TH=80°C, TL=75°C, and the o

DS17216 of 16R0, R1 = Thermometer Resolution Bits. Table 3 below defines the resolution of the digital thermometer,based on the settings of these two

DS17217 of 16If the user does not wish to take advantage of the thermostat capabilities of the DS1721, the 24 bits can beused for general storage of s

DS17218 of 16DATA TRANSFER ON 2-WIRE SERIAL BUS Figure 5Figure 6 details how data transfer is accomplished on the two-wire bus. Depending upon the sta

DS17219 of 162-WIRE SERIAL COMMUNICATION WITH DS1721 Figure 6