Hi @Vsv.1 ,
Let's see if I can help you.
>> Can you give more light on weight setting , offset setting for each axis. Is that offset unit is 'mg' or it is angle, the maximum value of THS is 6 bits, so how it will be related to a large angle value.
the AN4509 reports some of the thresholds related to the tilt degrees. Suppose you have your device with the z axis measuring 1g (flat position), the x and y axis will measure 0 LSB = 0 mg. If you set the threshold at 15° and enable X_WU and Y_WU (not the Z_WU), because the Z_WU would always generate an input when in flat position (Z = 1 g).
>> I have seen a conversion fs2tomg (multiplying with .016, may i know how arrived in this calculation), is there a calculation for raw to angle in the same way.
The conversion formula for the data output is the following one, and comes from the fact that the sensitivity is 0.244 mg/LSB and the output data is on 14-bit (i.e., you have to divide by 4 to get the 16-bit LSB). You can find in the datasheet p.6:
float_t lis2dw12_from_fs2_to_mg(int16_t lsb)
{
return ((float_t)lsb) * 0.061f;
}-Eleon
Hi @Eleon BORLINI . I was waiting to get my hardware which took for a rework and I have checked the scenarios.
The accelerometer read and calculating angle seems almost correct by the way you suggested for each axis, from 0 to but a maximum 85-86 degrees.
here is I calculated this,
if(!lis2dw12_acceleration_raw_get(&dev_ctx, data_raw_acceleration.u8bit))
{
acceleration_mg[0] = lis2dw12_from_fs2_to_mg(data_raw_acceleration.i16bit[0]);
*psXValue = asin((double_t)(acceleration_mg[0])/GRAVITYFACTOR)*RADIAN2DEG; //GRAVITYFACTOR =1000(mg to g) and RADIAN2DEG(180*3.14) }
>>the AN4509 reports some of the thresholds related to the tilt degrees. Suppose you have your device with the z axis measuring 1g (flat position), the x and y axis will measure 0 LSB = 0 mg. If you set the threshold at 15° and enable X_WU and Y_WU (not the Z_WU), because the Z_WU would always generate an input when in flat position (Z = 1 g).
For setting wakeup for tilt angles is not worked , I referred
https://www.st.com/resource/en/application_note/dm00401877-lis2dw12-alwayson-3d-accelerometer-stmicroelectronics.pdf. page no.22.
But What I have seen is the interrupt is generated for TAP events not tilt. The code I pasted below
dev_ctx.write_reg = platform_write;
dev_ctx.read_reg = platform_read;
dev_ctx.handle = &hi2c1;
lis2dw12_device_id_get(&dev_ctx, &whoamI);
if (whoamI != LIS2DW12_ID)
{
return error;
}
lis2dw12_reset_set(&dev_ctx, PROPERTY_ENABLE);
do {
lis2dw12_reset_get(&dev_ctx, &rst);
} while (rst);
lis2dw12_full_scale_set(&dev_ctx, LIS2DW12_2g);
lis2dw12_filter_path_set(&dev_ctx, LIS2DW12_USER_OFFSET_ON_OUT);
lis2dw12_power_mode_set(&dev_ctx, LIS2DW12_CONT_LOW_PWR_LOW_NOISE_12bit);
lis2dw12_wkup_dur_set(&dev_ctx, 0);
lis2dw12_offset_weight_set(&dev_ctx,1);
lis2dw12_wkup_threshold_set(&dev_ctx,2);
lis2dw12_usr_offset_x_set(&dev_ctx,0);
lis2dw12_usr_offset_y_set(&dev_ctx,0);
lis2dw12_usr_offset_z_set(&dev_ctx,1);
lis2dw12_pin_int1_route_get(&dev_ctx, &int_route.ctrl4_int1_pad_ctrl);
int_route.ctrl4_int1_pad_ctrl.int1_wu = PROPERTY_ENABLE;
lis2dw12_pin_int1_route_set(&dev_ctx, &int_route.ctrl4_int1_pad_ctrl);
lis2dw12_data_rate_set(&dev_ctx, LIS2DW12_XL_ODR_200Hz);
Note: I tried adding wakeup feed data set "lis2dw12_wkup_feed_data_set(&dev_ctx, 1)", but then TAP interrupt also stopped.
>> If you set the threshold at 15° and enable X_WU and Y_WU (not the Z_WU), because the Z_WU would always generate an input when in flat position (Z = 1 g).
Is it possible to enable/disable an axis from interrupt for wake up?. I have seen options enable/disable axis for tap interrupt only. Rather I think we might need to set offset only for the required axes, please correct me.
Regards,
Visakh SV
