电子的关键(TM1990A-F5)

electronic key,silca electronic key,TM card Smart Card (TM card, Information Button, Touch Memory) Type: TM1990A-F5 Dimension: diameter 16.25MM, high 5.9MM Function: anti-water, anti-shake, anti-rust; the shell is made by 304 stainless steel, never rust; the chip is made by new TM1990A wafer, unique 64bit serial number of the world. Full compatible with ds1990A(R) . TM1990A SPECIAL FEATURESl TM1990A is full compatible with DS1990A, DS1990R and i1990Al Unique 48bit serial numberl Low-cost electronic key for access controll 8-bit CRC for checking data integrityl Can be read in less than 5 msl Operating temperature range of -40°C to +85°CCOMMON INFORMATION BUTTON FEATURESl Unique, factory-lasered and tested 64-bitregistration number (8-bit family code + 48-bit serial number + 8-bit CRC tester) assuresabsolute traceability because no two parts arealike.l Multidrop controller for MicroLAN.l Digital identification by momentary contact.l Chip-based data carrier compactly stores information.l Data can be accessed while affixed to an object.l Economically communicates to bus master with a single digital signal at 16.3k bits per second.l Standard 16 mm diameter and 1-Wire protocol ensure compatibility with INFORMATION BUTTON family.l Button shape is self-aligning with cupshaped probes.l Durable stainless steel case engraved with registration number withstands harsh environments.l Easily affixed with self-stick adhesive backing, latched by its flange, or locked with a ring pressed onto its rim.l Presence detector acknowledges when reader first applies voltage.ORDER INFOMATIONTM1990A-F5-40C-+85CF5 ButtonESD BAG200PCS/BAG2BAG/BOXINFORMATION Button DESCRIPTIONThe TM1990A Serial Number INFORMATION BUTTON is a rugged data carrier that acts as an electronic registrationnumber for automatic identification. The TM1990A consists of a factory-lasered, 64-bit ROM thatincludes an unique 48-bit serial number, an 8-bit CRC and an 8-bit Family Code (01h). Data is transferredserially via the 1-Wire protocol which requires only a single data lead and a ground return. The TM1990Ais fully compatible with the TM1990A Serial Number INFORMATION BUTTON but provides the additional 1-Wire protocolcapability that allows the Search ROM command to be interpreted by the TM1990A and therefore allowsmultiple TM1990A devices to reside on a single data line.The durable MicroCan package is highly resistant to environmental hazards such as dirt, moisture andshock. Its compact coin-shaped profile is self-aligning with mating receptacles, allowing the TM1990A tobe used easily by human operators. Accessories permit the TM1990A to be mounted on plastic key tabs,photo ID badges, printed circuit boards or any smooth surface of an object. Applications include accesscontrol, work-in-progress tracking, tool management and inventory control.OPERATIONThe TM1990As internal ROM is accessed via a single data line. The 48-bit serial number, 8-bit familycode and 8-bit CRC are retrieved using the Dallas 1-Wire protocol. This protocol defines bus transactionsin terms of the bus state during specified time slots that are initiated on the falling edge of sync pulsesfrom the bus master. All data is read and written least significant bit first.1-WIRE BUS SYSTEMThe 1-Wire bus is a system which has a single bus master system and one or more slaves. In all instances,the TM1990A is a slave device. The bus master is typically a microcontroller. The discussion of this bussystem is broken down into three topics: hardware configuration, transaction sequence, and 1-Wiresignaling.Hardware ConfigurationThe 1-Wire bus has only a single line by definition; it is important that each device on the bus be able todrive it at the appropriate time. To facilitate this, each device attached to the 1-Wire bus must have anopen drain connection or 3-state outputs. The TM1990A is an open drain part with an internal circuitequivalent to that shown in Figure 2. The bus master can be the same equivalent circuit. If a bidirectionalpin is not available, separate output and input pins can be tied together. The bus master requires a pullupresistor at the master end of the bus, with the bus master circuit equivalent to the one shown in Figure 3.The value of the pullup resistor should be approximately 5 kW for short line lengths. A multidrop busconsists of a 1-Wire bus with multiple slaves attached. The 1-Wire bus has a maximum data rate of 16.3kbits per second.The 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 if the transaction is to resume. If this does not occur and the bus is left lowfor more than 120 ms, one or more of the devices on the bus may be reset.