Electronic Components Datasheet Search |
|
STS21 Datasheet(PDF) 8 Page - List of Unclassifed Manufacturers |
|
STS21 Datasheet(HTML) 8 Page - List of Unclassifed Manufacturers |
8 / 12 page Datasheet STS21 www.sensirion.com Version 2 – December 2011 8/12 5.6 User Register The content of User Register is described in Table 8. Please note that reserved bits must not be changed and default values of respective reserved bits may change over time without prior notice. Therefore, for any writing to the User Register, default values of reserved bits must be read first. Thereafter, the full User Register string is composed of respective default values of reserved bits and the remainder of accessible bits optionally with default or non-default values. Bit # Bits Description / Coding Default 7, 0 2 Measurement resolution „00‟ 14 bit „01‟ 12 bit „10‟ 13 bit „11‟ 11 bit „00‟ 6 1 Status: End of battery9 „0‟: VDD > 2.25V „1‟: VDD < 2.25V „0‟ 3, 4, 5 3 Reserved 2 1 Enable on-chip heater „0‟ 1 1 Disable OTP Reload „1‟ Table 8 User Register. Threshold value for End of Battery signal may vary by ±0.1V. Reserved bits must not be changed. “OTP reload” = „0‟ loads default settings after each time a measurement command is issued. The end of battery alert is activated when the battery power falls below 2.25V. OTP Reload is a safety feature and loads the entire OTP settings to the register, with the exception of the heater bit, before every measurement. This feature is disabled per default and is not recommended for use. Please use Soft Reset instead – it contains OTP Reload. An example for I2C communication reading and writing the User Register is given in Figure 15. 5.7 CRC Checksum STS21 provides a CRC-8 checksum for error detection. The polynomial used is x8 + x5 + x4 +1. For more details and implementation please refer to the application note “CRC Checksum Calculation for SHT2x”. 5.8 Serial Number STS21 provides an electronic identification code. For instructions on how to read the identification code please refer to the Application Note “Electronic Identification Code” – to be downloaded from the web page www.sensirion.com/SHT21. 9 This status bit is updated after each measurement 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 S 1 0 0 1 0 1 0 0 1 1 1 0 0 1 1 1 I2C address + write Read Register 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 S 1 0 0 1 0 1 0 1 0 0 0 0 0 0 1 0 I2C address + read Register content 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 S 1 0 0 1 0 1 0 0 1 1 1 0 0 1 1 0 I2C address + write Write Register 55 56 57 58 59 60 61 62 63 0 0 0 0 0 0 1 1 P Register content to be written Figure 15 Read and write register sequence – grey blocks are controlled by STS21. In this example, the resolution is set to 12bit. 6 Conversion of Signal Output Default resolution is set to 14 bit temperature reading. Measured data are transferred in two byte packages, i.e. in frames of 8 bit length where the most significant bit (MSB) is transferred first (left aligned). Each byte is followed by an acknowledge bit. The two status bits, the last bits of LSB, must be set to „0‟ before calculating physical values. In the example of Figure 12 and Figure 13, the transferred 16 bit temperature data is „0110‟0011‟0101‟0000‟ = 25424. 6.1 Temperature Conversion The temperature T is calculated by inserting temperature signal output ST into the following formula (result in °C), no matter which resolution is chosen: 16 T 2 S 175.72 46.85 T 7 Environmental Stability The SHT2x sensor series were tested based on AEC- Q100 Rev. G qualification test method where applicable. Sensor specifications are tested to prevail under the AEC- Q100 temperature grade 2 test conditions listed in Table 910. 10 Temperature range is -40 to 105°C (AEC-Q100 temperature grade 2). |
Similar Part No. - STS21 |
|
Similar Description - STS21 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |