Temperature Sensor Board
Contents
1. APPLICABLE LAWS ZILOGIC SYSTEMS EXPRESSLY DISCLAIMS ALL WARRANTIES EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT ZILOGIC SYSTEMS DOES NOT WARRANT THAT THE FUNCTIONS CONTAINED IN ZILOGIC SYSTEMS DEVELOPMENT KITS WILL MEET YOUR REQUIREMENTS OR THAT THE OPERATION WILL BE UNINTERRUPTED OR ERROR FREE OR THAT DEFECTS IN ZILOGIC SYSTEMS DEVELOPMENT KITS WILL BE CORRECTED FURTHERMORE ZILOGIC SYSTEMS DOES NOT WARRANT OR MAKE ANY REPRESENTATIONS REGARDING THE USE OR THE RESULTS OF THE USE OF THE ZILOGIC SYSTEMS DEVELOPMENT KITS IN TERMS OF THEIR CORRECTNESS ACCURACY RELIABILITY OR OTHERWISE SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OF IMPLIED WARRANTIES SO THE ABOVE EXCLUSION MAY NOT APPLY OR MAY BE LIMITED Limitation of Liability Zilogic Systems development kits are not designed authorised or warranted to be suitable for use in medical military aircraft space or life support equipment not in applications where failure or malfunction of a Zilogic Systems product can reasonably be expected to result in personal injury death or severe property or environmental damage Zilogic Systems accepts no liability for inclusion and or use of Zilogic Systems development kits in such equipment or applications and therefore such inclusion and or use is at the customer s own risk Zilogic Systems Page 92. T_CRIT assertion and switches OFF the DC OUT on T_CRIT de assertion DC OUT can be connected to a 12V fan to switch it on and off automatically on thermal critical points Figure 1 2 Block Diagram Remote Sensor DC Input Input Header SA56004A ON OFF INTR Control DC Output 5 Power Supply The temperature sensor board is powered from the motherboard through FRC 10 header The DC OUT can be used for controlling an external device like a fan or a relay If external device control is required an external 12V 1Amp DC power should be provided through the DC IN screw terminal or through the 12V IN power jack This will be driven out through DC OUT on T_CRIT assertion Output Voltage 12V Output Current 1A Polarity o e O 6 Remote Sensor For remote temperature measurement the Emitter Base diode of a BJT is used as the sensing element Note that two lead diodes cannot be used since the ideal factor of two lead diodes is incompatible with the temperature sensor The recommended transistors are listed below 2N3904 NPN 2N3906 PNP An example of an 2N3904 NPN transistor connected to the REMOTE SENSOR connecter is shown in the following diagram Zilogic Systems Page 2 Temperature Sensor Board User Manual Rev 1 0 Figure 1 3 Connecting Sensing Element Twister Pair Transistor REMOTE SENSOR 2N 3904 NPN The wires connecting the sensing element can be 8 inches long For longer wire l
3. Temperature Sensor Board User Manual 1 0 Oct 2011 ZILOGIC SYSTEMS Temperature Sensor Board User Manual Rev 1 0 This work is licensed under the Creative Commons Attribution Share Alike 2 5 India License To view a copy of this license visit http creativecommons org licenses by sa 2 5 in or send a letter to Creative Commons 171 Second Street Suite 300 San Francisco California 94105 USA Temperature Sensor Board User Manual Rev 1 0 Table of Contents 1 Temperature Sensor Board ua ae 1 Je OVEMIEW a isis 1 2 Board Features u ei 1 3 Locating Components esanari cc ee Zn anne een ea En re Ha a attentes 1 4 DESCHIPLION 100 A ota 1 D POWER SUPPLY messen an hen iaae 2 6 Remote Sensor ta italia 2 Ta Connectors and Head Suicide 3 8 SPeOcIfICAIONS turis 4 2 Board US toa 5 1 12C BUS OVGIVIGW une en Neta ended diana 5 2 Accessing Device Registers sise 5 3 Common Usage Scenarios cocos tritio lentas alert tent donnent nan intra 5 A L gal Informatio N cita a 9 1 GCODVINQ nase in ENEE DAE E EEA EE DES 9 EED e NE e E E E ee 9 Zilogic Systems Page iii Temperature Sensor Board User Manual Rev 1 0 Chapter 1 Temperature Sensor Board 1 Overview The temperature sensor board is based on NXP s SA56004 temperature sensor which can be interfaced through the l2C bus Temperatures can be measured with an accuracy of 1 C 2 Board Features e SA56004 PC temperature sensor Remote temperature meas
4. age Scenarios This section shows the pseudo code for various common usage scenarios The PC operations are represented by the following two functions data i2c_read dev_addr i2c_write dev addan data The dev_adar is the 7 bit 12C address of the device to read write data is the byte to be read written In the case of i2c_read the byte read from the device is returned In the case of i2c_write the byte to be written to the device is passed to the function Scenario I Measuring Local Temperature To measure the local temperature the following pseudo code can be used ltil res 007 i2c_write 0x48 lthb_reg temp i2c_read 0x48 o Write the register address of the local temperature register LTHB 0x0 Read the contents of LTHB The read byte is the local temperature in degree Celsius Scenario Il Measuring Remote Temperature The temperature sensing element is first connected to the SENSOR PORT as shown in the following diagram Zilogic Systems Page 5 Temperature Sensor Board User Manual Rev 1 0 Figure 2 2 Connecting Sensing Element Twister Pair Transistor REMOTE SENSOR 2N 3904 NPN The following pseudo code is used to measure the remote temperature rthb_reg 0x1 i2c_write 0x48 rthb_reg O temp i2c_read 0x48 O Write the register address of the remote temperature register RTHB 0x1 Read the contents of RTHB The read byte is the remote temperature in degree Cel
5. default T_CRIT setpoint is 85 C The default T_CRIT hysteresis is 10 C The following pseudo code sets the T_CRIT setpoint to 75 C and the hysteresis to 20 C Zilogic Systems Page 7 Temperature Sensor Board User Manual 00008 lcs_reg 12c_ write temp 75 LAC a th_reg 0 LAC NES hyst 20 LAC ee Write the register address of the local T_CRIT register LCS 0x20 CO 220 8 x48 0x48 x21 0x48 0x48 lcs_reg temp ASE A O th_reg o 0 Rev 1 0 Write the setpoint to LCs The local temperature setpoint in degree Celsius is written to the register Write the register address of the T_CRIT hysteresis register TH 0x21 Write the hysteresis amount to TH The hysteresis amount in degree Celsius is written to the register Zilogic Systems Page 8 Temperature Sensor Board User Manual Rev 1 0 Appendix A Legal Information 1 Copying This work is licensed under the Creative Commons Attribution Share Alike 2 5 India License To view a copy of this license visit http creativecommons org licenses by sa 2 5 in or send a letter to Creative Commons 171 Second Street Suite 300 San Francisco California 94105 USA 2 Disclaimers NO WARRANTY ZILOGIC SYSTEMS DEVELOPMENT KITS AND TECHNICAL SUPPORT IF ANY ARE PROVIDED AS IS AND WITHOUT ANY WARRANTY OF ANY KIND EXPRESS OR IMPLIED TO THE MAXIMUM EXTENT PERMITTED UNDER
6. e Max SCL frequency 7 bit Device Address Value 5V 550uA 600uA 40 C 125 C 2 C 3 C 1 C 3 C 2 2V 5 0V 0 0V 0 8V 400kHz 0x48 Condition 16Hz conversion rate FIXME 60 C to 100 C 40 C to 125 C 60 C to 100 C 40 C to 125 C Zilogic Systems Rev 1 0 Page 4 Temperature Sensor Board User Manual Rev 1 0 Chapter 2 Board Usage 1 2C Bus Overview The FC is a simple two wire interface for on board communication One of the wires is data and the other is clock The I C is a master slave bus The master is initiates the communication and the slaves respond to it Each slave on the bus has an address to uniquely identify itself Figure 2 1 PC Bus 0x48 0x24 Ox6A 0x2B 0x12 0x32 12C Master There are typical two operations that the master can perform i2c_read and i2c_write During the i2c_read operation the master specifies the slave address and the no of bytes to read During the i2c_write operation the master specifies the slave address and the bytes to be written 2 Accessing Device Registers The devices usually have a set of registers Each register is given an address When a register is to be read or written the address is first written to the device and then data is read or written to the register The register address specified is stored within the device For successive reads to the same register the address need not be specified again 3 Common Us
7. engths a shielded twisted pair is recommended Please see the recommendations under the section Mounting of the SA56004X data sheet 7 Connectors and Headers 7 1 12C Connector The temperature sensor board can be interfaced to a motherboard through the 12c 10 pin FRC connector The signal details are given below Table 1 1 FRC 10 Pin Connector Pin Signal Signal Type 1 VCC Supply from motherboard 2 Not Used 3 Not Used 4 SCL Open collector 5 SDA Open collector 6 Not Used 7 Not Used 8 Not Used 9 INTR TTL Out 10 GND E 7 2 REMOTE SENSOR Connector When a remote temperature has to be measured the remote temperature sensing elementis connected to the REMOTE SENSOR header Table 1 2 REMOTE SENSOR Connector Pin Signal GND 2 D 3 D 4 GND 7 3 DC OUT and DC IN Connector This DC OUT connector provides a 12V DC from the DC IN connector when T_CRIT is asserted This is typically used for controlling a fan or triggering a system shutdown when the temperature exceeds a configured critical set point Zilogic Systems Page 3 Temperature Sensor Board User Manual Table 1 3 DC OUT and DC IN Connector Pin Signal 1 VCC 2 GND 8 Specifications Table 1 4 Specifications Parameter Power Supply Supply Voltage Supply Current Temperature Measurement Range Local Temp Error Remote Temp Error PC Bus Input High Voltage Input Low Voltag
8. sius Scenario Ill Interrupt Notification In certain applications an action has to be taken when the temperature exceeds a specific temperature range This can be done by periodically reading the temperature register But a much more efficient method is possible The temperature sensor can interrupt the CPU when the temperature exceeds a specified range The CPU then performs the required action and acknowledges the interrupt Figure 2 3 Alert Interrupt 12C Bus 12C Temp Sensor ALARM The temperature sensor has an ALERT signal that can be used as an interrupt signal The set points for local and remote temperatures can be configured individually An example circuit configuration is shown in Figure 2 3 Alert Interrupt Note that since the ALERT is an open collector output a pull up resistor typically 10k is required The pseudo code for enabling interrupt notification when the local temperature exceeds the range 10 60 C is given below lhs_reg 0x0B i2c_write 0x48 lhs_reg temp 60 i2c_write 0x48 temp O lls_reg 0x0C i2c_write 0x48 lls_reg temp 10 i2c_write 0x48 temp O Write register address of the Local High Setpoint register LHS OxOB e Write local high setpoint temperature 60 C to LHS Zilogic Systems Page 6 Temperature Sensor Board User Manual Rev 1 0 e Write register address of the Local Low Setpoint register LLS OxOC O Write local low setpoin
9. t temperature 10 C to LLS The pseudo code for the interrupt handler in given below lthb_reg 0x0 i2c_write 0x48 lthb_reg temp i2c_read 0x48 sr_reg 0x2 i2c_write 0x48 sr reg status i2c read 0x48 O O Read the local temperature Read the status register to acknowledge the interrupt Scenario IV Thermal Watchdog In certain applications the temperature sensor is required to autonomously control an external device when the temperature exceeds a setpoint This must be done without the intervention of the software One such application is the thermal watchdog where the temperature sensor shuts down the system being monitored or switches a cooling fan when the temperature over shoots the setpoint Figure 2 4 Thermal Watchdog 12C Bus 12C Temp Sensor T_CRIT System Reset The temperature sensor can act like a thermal watchdog using the T_CRIT signal The T_CRIT becomes low when the temperature exceeds the T_CRIT setpoint The T_CRIT signal can in turn control a cooling fan The T_CRIT setpoint can be configured individually for local and remote temperatures An example circuit configuration is shown in Figure 2 4 Thermal Watchdog The T_CRIT is held low till the temperature drops by a configurable hysteresis amount hysteresis on the T_CRIT signal is shown in the figure below Figure 2 5 Hysteresis LCS 75 C LCS TH 55 C Local Temperature T_CRIT The
10. urement Over temperature alert interrupt External device control without software intervention LED indications for testing debugging Can measure temperatures from 40 C to 125 C 3 Locating Components The location of the components on the board is indicated in the following diagrams Figure 1 1 Front View Temperature Sensor Board pr ZILOGIC SYSTEMS 94V 0 N DC DC Input Output o Screw Terminal z Le DC Input Jack E m Remote Sensor Header m I2C 10 pin A Header a ZA TMPSEN P1 R1A MADE IN INDIA 4 Description A block diagram representation of the board is shown below The IC temperature sensor can be accessed through the 10 pin FRC connector from the motherboard The temperature sensor can measure the local IC temperature and a remote temperature For measuring remote temperatures a transistor connected to the REMOTE SENSOR port is used as the sensing element Zilogic Systems Page 1 Temperature Sensor Board User Manual Rev 1 0 An alert interrupt is raised when the temperature exceeds a configurable set point The signal T_CRIT is raised when the temperature exceeds a configurable critical set point This is useful for automatic temperature regulation applications where the system is to be shutdown or a fan is to be switched ON without software intervention The board provides a isolated 12V 1Amp power switching The board switches ON the 12V 1Amp DC OUT on
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