DS1701K MAXIM | Alldatasheet

Document overview

  • Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
  • PDF pages: 7

Technical content

Revision 1.0 2/99 Dallas Semiconductor Tech Support 972-371-4448 Web site:www.dalsemi.com Page 1 of 7 Features:

  • Full-Featured Evaluation Kit for the DS1701K with Temperature Sensor reading.
  • Compatible with WindowsTM 95, Windows TM 98, and WindowsTM NT Operating Systems.
  • Complete read/write access to all registers within the DS1701K devices and temperature reading for the DS1820, DS18B20, DS18S20, DS1821 and DS1822 devices.
  • Measures temperatures from the full range of the devices -55°C to +125°C. Fahrenheit equivalent is -67°F to +257°F.
  • Celsius and Fahrenheit temperature readings. Kit Contents: 1. Programming Software CD ROM containing DS1701K.exe Installer. 2. 87-1701K-000 Demo board. 3. DS1701K Demo Kit documentation on CD ROM. 4. DS1820, DS18B20, DS18S20, DS1821 and the DS1822 Demo Devices. 5. DS9123 Universal BrickTM serial port device and cable. To use the kit, you will also need: 1. An available Serial Port to connect the DS9123 Universal Brick TM modular data cable. 2. A +3 to +5 volt regulated power supply with banana jack leads. Introduction: The One-Wire board as shown in Figure 1.0 allows the user to test the functional capabilities of the Dallas Semiconductor thermal devices featuring the 1-wire interface. The circuitry allows the user to read the temperature, and to read and write the appropriate registers of the socketed device. Figure 1.0 1-Wire Board Block Diagram Setup and Installation The DS1701K program is a 32-bit application which is designed to run under Windows TM 95, WindowsTM 98 or WindowsTM NT. The DS1701K installer is designed to be loaded directly onto the user’s PC. The Setup.exe file is a compressed executable which prompts the user for the location and drive for installation, then the “Setup” files are placed on the user’s hard drive. You must run the “Setup” files to execute the DS1701K program files. Typically, the user will run Setup.exe from the Windows TM 95 “Start” menu. Typically, you can begin the installation process from the “Run” menu by opening DS1701K 1-Wire Temperature Sensor Evaluation Kit www.dalsemi.com Kit Instructions And Operating Procedures

Revision 1.0 2/99 Dallas Semiconductor Tech Support 972-371-4448 Web site:www.dalsemi.com Page 6 of 7 Multi-Drop Device Command Codes The following is a list of command codes for the DS1820, DS18S20, DS18B20 and DS1822 multi- drop devices. Convert T “44h” Convert T = 44 hexadecimal. This command begins a temperature conversion. The temperature conversion will be performed and " the multi-drop device" will remain idle. If the bus master issues read time slots following this command, the device will output 0 as long as it is busy making a temperature conversion. It will return a 1 when the temperature conversion is complete. If parasite powered, the bus master has to enable a strong pull-up for a period greater than t CONV immediately after issuing this command. Read Scratchpad “BEh” Read Scratchpad = BE hexadecimal. This command reads the contents of the scratchpad. The reading will commence at byte 0, and will continue until the 9th byte is read. If not all locations are to be read, the master may issue a reset to terminate reading at any time. Write Scratchpad “4Eh” Write Scratchpad = 4E hexadecimal. This command writes into the scratchpad, starting at the TH register. The next three bytes written will be saved in scratchpad memory at address locations 2 through 4. All three bytes must be written before the reset is issued. Address 4 of the DS1820 and the DS18S20 are reserved. Address 4 of the DS18B20 and the DS1822 are the Configuration registers. Copy Scratchpad “48h” Copy Scratchpad = 48 hexadecimal. This command copies the scratchpad into memory. Three bytes, address locations 2 through 4 are stored into memory. Relative to the speed of 1- Wire timing protocol, this operation can be considered immediate. Address 4 of the DS1820 and the DS18S20 are reserved and are not stored. Address 4 of the DS18B20 and the DS1822 are the Configuration registers and are stored along with the TH and TL registers. If parasite powered, the bus master has to enable a strong pull-up for a period greater than 10 ms immediately after issuing this command. Recall EE “B8h” Recall EE = B8 hexadecimal. This command recalls the temperature triggers TH, TL and the configuration values stored in memory. This recall happens automatically upon power-up so valid data is available in the scratchpad as soon as the device has power applied. With every read data time slot issued after this command has been sent, the device will output its temperature converter busy flag ; 0=busy, 1=ready. Read Power Supply “B4h” Read Power Supply = B4 hexadecimal. With every data time slot issued after this command has been sent, the device will signal its power mode. Parasite Power = 0, External Power Supplied = 1". During a typical read cycle the user will read either 0 or FF. Read ROM “33h” Read ROM = 33 hexadecimal. This command allows the bus master to read the 8-bit family code, unique 48-bit serial number and 8-bit CRC. This command can be used only if there is a single device on the bus. If more than one slave is present on the bus, a data collision will occur when all slaves try to transmit at the same time, producing a wired AND result. This command is not implemented in this evaluation kit. Match ROM “55h” Match ROM = 55 hexadecimal. The Match ROM command, followed by the 64-bit ROM code, allows the bus master to address a specific device on the multi-drop bus. Only the slave device that exactly matches the 64-bit ROM code will respond. All slave devices that do not match the code will wait for a reset pulse. This command is not implemented in this evaluation kit.

Revision 1.0 2/99 Dallas Semiconductor Tech Support 972-371-4448 Web site:www.dalsemi.com Page 7 of 7 Skip ROM “CCh” Skip ROM = CC hexadecimal. This command can save time in a single-drop bus system by allowing the bus master to access the device functions without providing the ROM code. If more than one slave is present on the bus, a data collision will occur when all slaves try to transmit at the same time, producing a wired AND result. Search ROM “F0h” Search ROM = F0 hexadecimal. The Search ROM command allows the bus master to use a process of elimination to identify the 64-bit ROM codes of all slave devices on the bus. The Search ROM process is the repetition of a simple 3-step routine. Read a bit, read the complement of the bit, write the desired value of that bit. The bus master performs this simple 3-step routine on each bit of the ROM. After one complete pass, the bus master has learned one ROM code for a single slave device. The remaining number of devices and their ROM codes may be identified by additional passes. Each device drops off the bus following identification of its ROM code. A reset command during the Search ROM puts all devices back on the bus. Therefore, a reset command is not recommended until all ROM codes are found. Alarm Search “ECh” Alarm Search = EC hexadecimal. The flow chart of this command is identical to that of the Search ROM algorithm. The slave device will only respond if an alarm condition has been encountered at the temperature measurement. An alarm condition is defined as a temperature higher than TH or lower than TL. The alarm condition remains set as long as the device is powered or until another temperature measurement reveals a non-alarming value. Following a change in the TH or TL settings, a temperature conversion should be done to validate the alarm condition. The Alarm Search function is not implemented in this evaluation kit because this function requires that at least one multi-drop device be in alarm. Otherwise, no communication between the device and the software can occur. Since we require a response each and every time we communicate through the DS9123 (which will not be in alarm), this function is omitted.