spi- /i 2 c- compatible temperature sensor and 8 - channel analog - to - digital converter silicon anomaly adt7411 this anomaly list d escribes the known bugs, anomalies , and workarounds for the adt741 1 and applies t o all adt7411 generics as supplied by analog devices, inc. analog devices is committed, through future si licon revisions, to continuously improving silicon functionality. analog devices tries to ensure that these future silicon revisions remain compatible with your present software/systems implementing the recommended workarounds outlined here. adt7411 functionality issues silicon revision ide ntifier kernel revision identifier chip marking silicon status anomaly sheet no. of reported anomalies 1.00 a ll silicon branded adt7411 release rev. 1 1 r elease r e v. a 4 rev. a document feedback information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. specifications subject to change without notice. no license is granted by implication or otherwise under any patent or patent rights of analog devices. trademarks and registered trademarks are the property of their respective owners. o ne technology way, p.o. box 9106, norwood, ma 02062 - 9106, u.s.a. tel: 781.329.4700 ? 2006 C 2014 analog devices, in c. all rights reserved. technical support www.analog.com
adt7411 silicon anomaly anomalies table 1 . averaging function [er001 ] background averaging mode may output incorr ect measurements before giving a final result . issue averaging mode enabled (for any channel) may output incorrect results. workaround d isable the averaging function by setting c5 = 1 in the control configuration 2 register. the user may still accomplish averaging by reading back 16 conversions and averaging all 16 readings to get a value that has reduced noise levels. related issues none . table 2 . round robin ( fast clock m ode o nly ) [ er002 ] background e rroneous results can be read in termittently in round robin fast clock mode ( spi and i 2 c ) . issue a s the temperature of the device is ramped from cold to hot , irregu lar temperature and/or voltage measurements may be obtained. workarounds enable slow clock mode by setting c0 = 0 in the control configuration 3 register. related issues none. table 3 . single channel (continuous monitoring mode o nly ) [ er003 ] background changing a cha nnel in single channel continuous monitoring mode during a conversion can result in data being written into the new channel register instead of the previous register (spi and i 2 c ) . issue an error can be obtained where the da ta read back appears from the previous converted channel instead of the current channel . workaround disable continuous monitoring before changing a channel. once a channel is selected , turn monitoring on , wait for a conversion and then turn monitoring off . wait one conversion period to allow any in progress conversion to complet e before changing the channel; t hen take a measurement. the recommended list of steps are described in the workaround steps for the er003 section. related issues none. workaround steps for the er003 e nable single channel mode by setting c4 = 1 in the c ontrol configuration 2 register. 2. set m onitoring off ( set c0 = 0 in the control configuration 1 register ) . 3. select a channel , for example , the channel for i nternal tem perature (write 0x71 to control configuration 2 register ) . 4. set m onitoring on (bit c 0 = 1 in the control configuration 1 register ) . 5. wait 2x the typical conversion time for the channel selected ( depending on which one is being measured , the power supply [ vdd ] or the analog input [ ain ]) and 3x the typical conversion time for the temperature conversion . 6. set m onitoring off (bit c 0 = 0 in the control configuration 1 register ) . 7. wait 1x the typical conversion time to allow any in progress conversion to complete before changing the channel. 8. take a measurement . 9. select the next channel (go back to step 3). table 4 . software reset (round robin o nly ) [ er004 ] background erroneous results can be read if resetting the part repeated ly in round r obin mode . issue resetting the part repeatedly by setting b it c7 1 in control configuration 2 , can cause all data registers to read back 00 after several software resets . workaround power down the part by s et ting b it d7 (pd) = 1 in control configuration 1 and power up the part again by clear ing b it d7 = 0 in control configuration 1 , just before asserting the software r eset bit in c ontrol configuration 2 . related issues none. ? 2006 C 2014 analog devices, inc. all rights reserved. trademarks and r egistered trademarks are the property of their respective owners. s02882 - 0 - 8/14(a)
|
