DS1921H/DS1921Z High-Resolution Thermochron iButton Devices Button shape is self-aligning with cup-shaped SPECIAL FEATURES probes Digital thermometer measures temperature in Durable stainless steel case engraved with 1/8C increments with 1C accuracy registration number withstands harsh Built-in real-time clock (RTC) and timer has environments accuracy of 2 minutes per month from 0C Easily affixed with self-stick adhesive to +45C backing, latched by its flange, or locked with Water resistant or waterproof if placed inside a ring pressed onto its rim DS9107 iButton capsule (Exceeds Water Presence detector acknowledges when reader Resistant 3 ATM requirements) first applies voltage Automatically wakes up and measures temperature at user-programmable intervals from 1 to 255 minutes PIN CONFIGURATION Logs consecutive temperature measurements 5.89 in 2KB of datalog memory 0.51 Records a long-term temperature histogram with 1/2C resolution 16.25 Programmable temperature-high and temperature-low alarm trip points D6 21 17.35 Records up to 24 time stamps and durations 3B2000FBC52B 1-Wire when temperature leaves the range specified Thermochron by the trip points 512 bytes of general-purpose battery-backed SRAM IO GND Communicates to host with a single digital signal at 15.4kbits or 125kbits per second All dimensions are shown in millimeters. using 1-Wire protocol Fixed range: H: +15C to +46C ORDERING INFORMATION Z: -5C to +26C PART TEMP RANGE PIN-PACKAGE COMMON iButton DEVICE DS1921H-F5 +15 C to +46C F5 Can DS1921Z-F5 -5 C to +26C F5 Can FEATURES Denotes a RoHS-compliant device that may include lead(Pb) that is Digital identification and information by exempt under the RoHS requirements. momentary contact Unique, factory-lasered and tested 64-bit EXAMPLES OF ACCESSORIES registration number (8-bit family code + 48- DS9096P Self-Stick Adhesive Pad bit serial number + 8-bit CRC tester) assures DS9101 Multi-Purpose Clip absolute traceability because no two parts are DS9093RA Mounting Lock Ring alike DS9093A Snap-In Fob Multidrop controller for 1-Wire net DS9092 iButton Device Probe Chip-based data carrier compactly stores information Data can be accessed while affixed to object Thermochron, iButton, and 1-Wire are registered trademarks of Maxim Integrated Products, Inc. 1 of 45 19-4887 Rev 11/13 DS1921H/Z iButton DEVICE DESCRIPTION The DS1921H/Z Thermochron iButton devices are rugged, s-esluffficient systems that measure temperature and record the result in a protected memory section. The recording is done at a use-rdefined rate, both as a direct storage of temperature values as well as in the form of a histogram. Up to 2048 temperature values taken at equidistant intervals ranging from 1 to 255 minutes can be stored. The histogram provides 64 data bins with a resolution of 0.5C. If the temperature lea-ves a user programmable range, the DS1921H/Z will also record when this happened, for how long the temperature stayed outside the permitted range, and if the temperature was too high or too low. Additional 512 bytes of general-purpose battery-backed SRAM allow storing information pertaining to the object to which the DS1921H/Z is associated. Data is transferred serially via th-e W1ire protocol, which requires only a single data lead and a ground return. Every DS1921H/Z is factlorasye-red with a guaranteed unique electrically readable 64-bit registration number that allows for absolute traceability. The durable stainless steel package is highly resistant to environmental hazards such as dirt, moisture, and shock. Accessories permit the DS1921H/Z to be mounted on almost any object, including containers, pallets, and bags. APPLICATION The DS1921Z is an ideal device to monitor the temperature of any object it is attached to or shipped with, such as fresh produce, medical drugs and supplies. It is also ideal for use in refrigerators. The DS1921H is intended for monitoring the body temperature of humans and animals and for monitoring temperature critical processes such as curing, powder coating, and painting. Alternatively, the DS1921H can be used for monitoring the temperature of clean rooms, and computer and equipment rooms. It can aalsido in calculating the proportional share of heating cost of each party buiin ldings with central heating. The DS1921H has a fixed range of +15C to +46C. The DS1921Z has a fixed range of- 5C to +26C. The high resolution makes the DS1921H and DS1921Z suitable for scientific research and developmentTh. e general-purpose battery-backed SRAM can store information such as shipping manifests, dates of manufacture, or other relevant data written as ASCII or encrypted files. Note that the initial sealing level of DS1921H/Z achieves the equivalent of IP56. Aging and use conditions can degrade the integrity of the seal over time, so for applications with significant exposure to liquids, sprays, or other similar environments, it is recommended to place the Thermochron in the DS9107 iButton capsule. The DS9107 provides a watertight enclosure that has been rated to IP68 (refer to Application Note 4126). OVERVIEW The block diagram in Figure 1 shows the relationships between the major control and memory sections of the DS1921H/Z. The device has seven main data components: 1)bi t 64laser- ed ROM 2) 256b-it scratchpad 3) 4096-bit general-purpose SRAM 4) 256bi- t register page of timekeeping, control, and counter registers 5) 96 bytes of alarm time stamp and duration logging memory 6) 128 bytes of histogram memory and 7) 2048 bytes of datalogm emory. Except for the ROM and the scratchpad, all other memory is arranged in a single linear address space. All memory reserved for logging purposes, counter registers and several other registers are read-only for the user. The timekeeping and control registers are write-protected while the device is programmed for a mission. The hierarchical structure of the 1-Wire protocol is shown in Figure 2. The bus master must first provide one of the seven ROM function commands: 1) Read ROM 2) Match ROM c3)h ROMSear 4) Conditional Search ROM 5) Skip ROM 6) Overdriv-eSkip ROM or 7) Overdrive-Match ROM. Upon completion of an Overdrive ROM command byte executed at standard speed, the device will enter Overdrive mode, where all subsequent communication occurs at a higher speed. The protocol required for these ROM function commands is described in Figure 13. After a ROM function command is successfully executed, the memory functions become accessible and the master may provide any one of the seven available commands. The protocol for these memory function commands is described in Figure 10. All data is read and written least significant bit first. 2 of 45