From 24a243843ef771273c81536c0bd18c5d70c010f4 Mon Sep 17 00:00:00 2001 From: Andrew Tridgell Date: Wed, 4 Dec 2013 22:54:02 +1100 Subject: lsm303d/l3gd20: change filters to 50Hz analog on-chip filters after discussion with Leonard these analog on-chip filters should be at 50Hz --- src/drivers/l3gd20/l3gd20.cpp | 11 ++++++++--- src/drivers/lsm303d/lsm303d.cpp | 7 ++++++- 2 files changed, 14 insertions(+), 4 deletions(-) diff --git a/src/drivers/l3gd20/l3gd20.cpp b/src/drivers/l3gd20/l3gd20.cpp index 103b26ac5..17b53bfa9 100644 --- a/src/drivers/l3gd20/l3gd20.cpp +++ b/src/drivers/l3gd20/l3gd20.cpp @@ -93,10 +93,15 @@ static const int ERROR = -1; /* keep lowpass low to avoid noise issues */ #define RATE_95HZ_LP_25HZ ((0<<7) | (0<<6) | (0<<5) | (1<<4)) #define RATE_190HZ_LP_25HZ ((0<<7) | (1<<6) | (0<<5) | (1<<4)) +#define RATE_190HZ_LP_50HZ ((0<<7) | (1<<6) | (1<<5) | (0<<4)) #define RATE_190HZ_LP_70HZ ((0<<7) | (1<<6) | (1<<5) | (1<<4)) #define RATE_380HZ_LP_20HZ ((1<<7) | (0<<6) | (1<<5) | (0<<4)) +#define RATE_380HZ_LP_25HZ ((1<<7) | (0<<6) | (0<<5) | (1<<4)) +#define RATE_380HZ_LP_50HZ ((1<<7) | (0<<6) | (1<<5) | (0<<4)) #define RATE_380HZ_LP_100HZ ((1<<7) | (0<<6) | (1<<5) | (1<<4)) #define RATE_760HZ_LP_30HZ ((1<<7) | (1<<6) | (0<<5) | (0<<4)) +#define RATE_760HZ_LP_35HZ ((1<<7) | (1<<6) | (0<<5) | (1<<4)) +#define RATE_760HZ_LP_50HZ ((1<<7) | (1<<6) | (1<<5) | (0<<4)) #define RATE_760HZ_LP_100HZ ((1<<7) | (1<<6) | (1<<5) | (1<<4)) #define ADDR_CTRL_REG2 0x21 @@ -662,15 +667,15 @@ L3GD20::set_samplerate(unsigned frequency) } else if (frequency <= 200) { _current_rate = 190; - bits |= RATE_190HZ_LP_70HZ; + bits |= RATE_190HZ_LP_50HZ; } else if (frequency <= 400) { _current_rate = 380; - bits |= RATE_380HZ_LP_100HZ; + bits |= RATE_380HZ_LP_50HZ; } else if (frequency <= 800) { _current_rate = 760; - bits |= RATE_760HZ_LP_100HZ; + bits |= RATE_760HZ_LP_50HZ; } else { return -EINVAL; } diff --git a/src/drivers/lsm303d/lsm303d.cpp b/src/drivers/lsm303d/lsm303d.cpp index a38524c22..701947b98 100644 --- a/src/drivers/lsm303d/lsm303d.cpp +++ b/src/drivers/lsm303d/lsm303d.cpp @@ -631,7 +631,12 @@ LSM303D::reset() accel_set_range(LSM303D_ACCEL_DEFAULT_RANGE_G); accel_set_samplerate(LSM303D_ACCEL_DEFAULT_RATE); accel_set_driver_lowpass_filter((float)LSM303D_ACCEL_DEFAULT_RATE, (float)LSM303D_ACCEL_DEFAULT_DRIVER_FILTER_FREQ); - accel_set_onchip_lowpass_filter_bandwidth(0); // this gives 773Hz + + // we setup the anti-alias on-chip filter as 50Hz. We believe + // this operates in the analog domain, and is critical for + // anti-aliasing. The 2 pole software filter is designed to + // operate in conjunction with this on-chip filter + accel_set_onchip_lowpass_filter_bandwidth(LSM303D_ACCEL_DEFAULT_ONCHIP_FILTER_FREQ); mag_set_range(LSM303D_MAG_DEFAULT_RANGE_GA); mag_set_samplerate(LSM303D_MAG_DEFAULT_RATE); -- cgit v1.2.3