Tactical Grade, Ten Degrees of Freedom Inertial Sensor Silicon Anomaly ADIS16488A This anomaly list describes the known bugs, anomalies, and workarounds for the ADIS16488A. Analog Devices, Inc., is committed, through future silicon revisions, to continuously improve silicon functionality. Analog Devices tries to ensure that these future silicon revisions remain compatible with your present software/systems by implementing the recommended workarounds outlined within this document. PERFORMANCE ISSUES Table 1. Error in Soft Iron Correction Factors er001 Background The signal chain for the tri-axis magnetometer in the ADIS16488A includes a user-configurable, 3 3 soft iron correction matrix. Users configure each value in the soft iron correction matrix by writing to its corresponding register. For example, 15 the SOFT IRON S12 register contains the value for correction factor S12. In these registers, 1 LSB = 100/2 . 15 Issue On units that have firmware Revision 1.07 (or earlier), 1 LSB = 12.5/2 , which is eight times lower than the correct value, on the following registers: SOFT IRON S12, SOFT IRON S13, SOFT IRON S21, SOFT IRON S31, and SOFT IRON S32. Workaround Read FIRM REV to determine the firmware revision of a unit. If FIRM REV < 0x0108, clear all soft iron correction values (write 0x0000 to each SOFT IRON Sxy register) and perform the soft iron correction outside of the ADIS16488A. Related Issues None. Table 2. User Offset Addition Error er002 Background The ADIS16488A provides user-configurable bias correction values for each gyroscope and accelerometer(x, y, and z), through the following registers: XG BIAS HIGH, XG BIAS LOW, YG BIAS HIGH, YG BIAS LOW, ZG BIAS HIGH, ZG BIAS LOW, XA BIAS HIGH, XA BIAS LOW, YA BIAS HIGH, YA BIAS LOW, ZA BIAS HIGH, and ZA BIAS LOW. On units that have firmware Revision 1.07 (or earlier), there is a computation error that results in a small error in the bias of Issue each sensor (for example, less than 0.02/sec for the gyroscopes). Workaround Read FIRM REV to determine the firmware revision of a unit. If FIRM REV < 0x0108, write 0x0000 to XG BIAS HIGH, XG BIAS LOW, YG BIAS HIGH, YG BIAS LOW, ZG BIAS HIGH, ZG BIAS LOW, XA BIAS HIGH, XA BIAS LOW, YA BIAS HIGH, YA BIAS LOW, ZA BIAS HIGH, and ZA BIAS LOW. Apply the bias correction factors to the gyroscope and accelerometer signals outside of the ADIS16488A. Related Issues None. Table 3. Temperature Compensation Error er003 Background The ADIS16488A leverages internal temperature sensors as control inputs for the compensation of gyroscope and accelerometer measurements. Issue On units that have firmware Revision 1.08 (or earlier), one of the three temperature sensors can be corrupted when using an external clock to drive the sampling. The external clock causes elevated levels of sensitivity to variation in temperature. Workaround Read FIRM REV to determine the firmware revision of a unit. If FIRM REV < 0x0109, use the internal sample clock if the best temperature sensitivity is necessary. Related Issues None. Table 4. Real-Time Clock (RTC) Functional Issues er004 Background The ADIS16488A provides a RTC function that keeps track of time (seconds, minutes, hours, days, months, and years) while the main processor function is not operating (sleep, powered off ). Issue On units that have firmware Revision 1.08 (or earlier), the days information in TIME DH OUT can experience an overflow condition when the device recovers from sleep mode. Read FIRM REV to determine the firmware revision of a unit. If FIRM REV < 0x0109, do not use sleep mode if the RTC Workaround function is critical for the application. Related Issues None. Rev. 0 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 2017 Analog Devices, Inc. All rights reserved. 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. Technical Support www.analog.com ADIS16488A Silicon Anomaly Table 5. Erroneous Barometer Self Test Result in DIAG STS er005 Background The DIAG STS register provides an error flag for the self test function in Bit 11. Issue On units that have firmware Revision 1.08 (or earlier), Register DIAG STS, Bit 11 may remain in a low state, even if the barometer is failing its self test routine. Workaround Read FIRM REV to determine the firmware revision of a unit. If FIRM REV < 0x0109, do not use Register DIAG STS, Bit 11 to determine the health of the barometer for mission critical functions. Related Issues None. Table 6. Barometer New Data Bit Continues Updating After Failure er006 Background Register SYS E FLAG, Bit 9 indicates that there is new barometer data in the BAROM OUT register when it is in a high state. Issue On units that have firmware Revision 1.08 (or earlier), Register SYS E FLAG, Bit 9 still indicates that new data is available, even if the barometer has experienced a failure. Workaround Read FIRM REV to determine the firmware revision of a unit. If FIRM REV < 0x0109, do not use Register SYS E FLAG, Bit 9 to determine the operational state of the barometer function. Related Issues None. Table 7. Sleep Mode Recovery Causes Barometer Failure er007 Background The ADIS16488A provides a sleep mode that has a faster recovery time than a complete restart (power-on or reset recovery). Issue On units that have firmware Revision 1.08 (or earlier), recovery from sleep mode can cause failure in the barometer function. Workaround Read FIRM REV to determine the firmware revision of a unit. If FIRM REV < 0x0109, do not use sleep mode if the barometer is important for the application. Related Issues None. Table 8. Writing to Register FNCTIO CTRL Causes Barometer Failure er008 Background The FNCTIO CTRL register provides a number of user configurations for the input/output lines (DIO1, DIO2, DIO3, and DIO4). Issue On units that have firmware Revision 1.08 (or earlier), writing to the FNCTIO CTRL register can cause the barometer measurement function to lock up. Workaround Read FIRM REV to determine the firmware revision of a unit. If FIRM REV < 0x0109 and the barometer function is important for the application, reset the operation after writing to Register FNCTIO CTRL and after backing up those settings in the flash. Related Issues None Table 9. Writing to Register GLOB CMD, Bit 1 Causes Barometer Failure er009 Background The Register GLOB CMD, Bit 1 provides a trigger bit for running the self test function on all of the sensors inside of the ADIS16488A. On units that have firmware Revision 1.08 (or earlier), running the self test routine by setting Register GLOB CMD, Bit 1 equal to 1 Issue can cause the barometer measurement function to lock up. Workaround Read FIRM REV to determine the firmware revision of a unit. If FIRM REV < 0x0109 and the barometer function is important for the application, reset the operation after running the self test function. Related Issues None Table 10. Daylight Savings Time Error in Real-Time Clock er010 Background The ADIS16488A provides a RTC function that keeps track of time (seconds, minutes, hours, days, months, and years) while the main processor function is not operating (sleep, powered off ). Register CONFIG, Bit 1 provides a control for managing against daylight savings time. Issue On units that have firmware Revision 1.08 (or earlier), turning daylight savings time on by setting Register CONFIG, Bit 1 equal to 1 causes a malfunction in the tracking of the RTC. Workaround Read FIRM REV to determine the firmware revision of a unit. If FIRM REV < 0x0109, do not use the daylight savings time setting of Register CONFIG, Bit 1 equal to 1. Related Issues None Rev. 0 Page 2 of 3