Programmable Dual-Axis Inclinometer/Accelerometer Silicon Anomaly ADIS16201 ADIS16201 ANOMALIES This anomaly list describes the known bugs, anomalies, and workarounds for the ADIS16201. 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 here. ADIS16201 FUNCTIONALITY ISSUES Silicon Kernel Revision Revision Silicon Identifier Identifier Chip Marking Status Anomaly Sheet No. of Reported Anomalies N/A N/A Date code = xx1333 Release Rev. A 6 xx = unrelated to date MANUAL FLASH MEMORY UPDATE FAILURES er001 Background The ADIS16201 uses a dual memory structure to maintain its operational configuration. The RAM register structure controls the operation of the device and the Flash/EE memory contents determine what is loaded into the RAM at start-up and during reset recovery events. The Flash/EE memory is updated by using a control bit in the COMMAND register of this part. Issue Flash/EE memory update was failing at a rate of approximately 5%. Date Code 0718 and older can exhibit this behavior. If it is encountered, use the STATUS register to check for a failed Workaround Flash/EE memory update if the error flag indicates a failure, try it again. Related Issues None. SCALE CALIBRATION REGISTER MATH ERROR er002 Background The ADIS16201 provides scale correction registers to accommodate calibration adjustments after system-level installation. These registers are XACCL SCALE, YACCL SCALE, XINCL SCALE, and YINCL SCALE. Issue The lower byte of the scale adjustment registers was not computing correctly. Small adjustments result in large output errors. Workaround Date Code 0750 and older can exhibit this behavior. Firmware Revision 1.5 fixed this issue. Verify this by reading the contents of 0x52 (lower byte) which is 0x15, if the fix is in place. If it is equal to 0x14 or lower, this issue exists on the part. If scale adjustment is not used, the device operates without error. Related Issues None. STATUS REGISTER NOT CLEARING WHEN READ er003 Background The STATUS register contains various diagnostic error flags, which clear when read. Issue The STATUS register clears when Address 0x3D is read, but not when Address 0x3C is read. Date Code 0750 and older can exhibit this behavior. Firmware Revision 1.5 fixed this issue. Verify this by reading the Workaround contents of 0x52 (lower byte) which is 0x15, if the fix is in place. If it is equal to 0x14 or lower, this issue exists on the part. If this issue is encountered, switch the read address to 0x3D to clear the flags. Related Issues None. Rev. A 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 www.analog.com license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Fax: 781.461.3113 20082014 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. ADIS16201 Silicon Anomaly AUTONULL FUNCTION RESULTS FAILS UNDER NEGATIVE ACCELERATION er004 The autonull function simply measures the output of each acceleration and inclinometer register and then loads an equal Background but opposite value into the user-configurable offset null registers. This restores the outputs to zero. Issue When a negative acceleration acts upon the device during the auto null, it can return a positive output, rather than zero. Workaround Date Code 0750 and older can exhibit this behavior. Firmware Revision 1.5 fixed this issue. Verify this by reading the contents of 0x52 (lower byte) which is 0x15, if the fix is in place. If it is equal to 0x14 or lower, this issue exists on the part. If this issue is encountered, manual calibration adjustment is a better option. Related Issues None. ALM SMPL1/ALM SMPL2 WRITES CAUSE DEVICE FAILURE er005 Background The ALM SMPL1 and ALM SMPL2 registers provide critical timing configuration data for rate-of-change alarm settings limited to one byte. The upper bytes of this register are documented as not used. Issue Writing to the upper byte of these registers causes a device failure. Workaround Date Code 0750 and older can exhibit this behavior. Firmware Revision 1.5 fixed this issue. Verify this by reading the contents of 0x52 (lower byte) which is 0x15, if the fix is in place. If it is equal to 0x14 or lower, this issue exists on the part. Do not attempt to write to the upper bytes of these registers, which are located at Address 0x25 and Address 0x27. Related Issues None. START-UP BEHAVIOR er006 Background The ADIS16201 uses a number of internal functions (accelerometer, ADC, DAC, I/O, clock, voltage reference) to produce the accelerometer/inclination outputs with respect to gravity. Once the power supply to the ADIS16201 reaches 2.35 V, the ADIS16201 begins its power-on sequence to initialize and start each of these functions. The ADIS16201 uses an internal processor core and firmware to facilitate this power-on sequence. Issue On a small percentage of units that have Date Code 1333 (or lower), the start-up process occasionally exhibits behaviors that preclude correct initialization of the internal ADC. The observable symptoms include (but not limited to) the following: SUPPLY OUT register will return a value ~120 mV lower than the supply voltage to the part. TEMP OUT register will return a value ~20C greater than expected. XACCL OUT, YACCL OUT will return a value ~120 mG lower than expected. XINCL OUT, YINCL OUT will return a value 6 to 7 off from the expected value. Investigation of this phenomenon has found that the anomalous start-up behavior only occurs on a very small percentage of ADIS16201 units. On units that show this phenomenon, there appears to be a very small window of temperature that may cause the problem to occur. For example, some devices that show this power-on issue occur when the ADIS16201 temperature is within a 1 to 2C window between the 40C to +105C operating temperature. Workaround For those with unused material (not solder-attached to a PCB), use units that have Date Code 1333 (or higher). These units have a firmware Revision 1.6, which modifies the power-on initialization sequence in a manner that helps to prevent the microcontroller for initializing incorrectly during initial power-on. Note that the firmware revision resides in an undocumented register location, at Address 0x52 and uses and 8-bit, 2-digit binary-coded decimal (BCD) format. Reading Address 0x52 returns a 16-bit number, which represents Address 0x52 and Address 0x53. Mask off the upper 8-bits to eliminate contents from Address 0x53 and use the remaining 8-bits to determine the firmware revision of the ADIS16201. The lower nibble represents the ones digit. For example, 0x15 would represent firmware Revision 1.5, which indicates that the unit does not employ the updated power-on sequence. If the location contains the hexadecimal number of 0x16, then the unit uses firmware Revision 1.6, which employs the updated power-on sequence. For those who are observing this issue in existing systems, develop a detection routine that leverages one or more of the six register-specific symptoms, depending on the specific application. Systems that start-up in the same orientation can leverage historical information on the xINCL OUT and xACCL OUT and check to see if the values are within 5, because this behavior causes an angle error of 6 to 7. When that is not practical, checking for negative changes in SUPPLY OUT, which exceed 100 mV in magnitude offer another opportunity for detecting this condition. When this condition is detected, cycle the power to the device and check for the same conditions after the start-up process completes. While one power cycle is typically sufficient, some cases may require additional power cycles. Related Issues None. Rev. A Page 2 of 4