DRV2605L Datasheet, PDF (27/69 Pages) Texas Instruments – DRV2605L 2 to 5.2 V Haptic Driver for LRA and ERM With Effect Library and Smart-Loop Architecture

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DRV2605L
SLOS854C – MAY 2014 – REVISED SEPTEMBER 2014
Programming (continued)
The following instructions list the step-by-step register configuration for auto-calibration. For additional details see
the Register Map section.
1. Apply the supply voltage to the DRV2605L device, and pull the EN pin high. The supply voltage should allow
for adequate drive voltage of the selected actuator.
2. Write a value of 0x07 to register 0x01. This value moves the DRV2605L device out of STANDBY and places
the MODE[2:0] bits in auto-calibration mode.
3. Populate the input parameters required by the auto-calibration engine:
(a) ERM_LRA — selection will depend on desired actuator.
(b) FB_BRAKE_FACTOR[2:0] — A value of 2 is valid for most actuators.
(c) LOOP_GAIN[1:0] — A value of 2 is valid for most actuators.
(d) RATED_VOLTAGE[7:0] — See the Rated Voltage Programming section for calculating the correct
register value.
(e) OD_CLAMP[7:0] — See the Overdrive Voltage-Clamp Programming section for calculating the correct
register value.
(f) AUTO_CAL_TIME[1:0] — A value of 3 is valid for most actuators.
(g) DRIVE_TIME[3:0] — See the Drive-Time Programming for calculating the correct register value.
(h) SAMPLE_TIME[1:0] — A value of 3 is valid for most actuators.
(i) BLANKING_TIME[3:0] — A value of 1 is valid for most actuators.
(j) IDISS_TIME[3:0] — A value of 1 is valid for most actuators.
(k) ZC_DET_TIME[1:0] — A value of 0 is valid for most actuators.
4. Set the GO bit (write 0x01 to register 0x0C) to start the auto-calibration process. When auto calibration is
complete, the GO bit automatically clears. The auto-calibration results are written in the respective registers
as shown in Figure 25.
5. Check the status of the DIAG_RESULT bit (in register 0x00) to ensure that the auto-calibration routine is
complete without faults.
6. Evaluate system performance with the auto-calibrated settings. Note that the evaluation should occur during
the final assembly of the device because the auto-calibration process can affect actuator performance and
behavior. If any adjustment is needed, the inputs can be modified and this sequence can be repeated. If the
performance is satisfactory, the user can do any of the following:
(a) Repeat the calibration process upon subsequent power ups.
(b) Store the auto-calibration results in host processor memory and rewrite them to the DRV2605L device
upon subsequent power ups. The device retains these settings when in STANDBY mode or when the EN
pin is low.
(c) Program the results permanently in nonvolatile, on-chip OTP memory. Even when a device power cycle
occurs, the device retains the auto-calibration settings. See the Programming On-Chip OTP Memory
section for additional information.
8.5.7 Programming On-Chip OTP Memory
The OTP memory can only be written once. To permanently program the OTP memory in registers 0x16 through
0x1A, use the following steps:
1. Write registers 0x16 through 0x1A with the desired configuration and calibration values which provide
satisfactory performance.
2. Ensure that the supply voltage (V_DD) is between 4 V and 4.4 V. This voltage is required for the nonvolatile
memory to program properly.
3. Set the OTP_PROGRAM bit by writing a value of 0x01 to register 0x1E. When the OTP memory is written
which can only occur once in the device, the OTP_STATUS bit (in register 0x1E) only reads 1.
4. Reset the device by power cycling the device or setting the DEV_RESET bit in register 0x01, and then read
registers 0x16 to 0x1A to ensure that the programmed values were retained.
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