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bma421: Change acceleration values to 'binary milli-G' units

Co-authored-by: FintasticMan <finlay.neon.kid@gmail.com>
This commit is contained in:
Graham Jones 2024-02-11 19:46:26 +00:00 committed by GitHub
parent a49dc15a6e
commit c2c53bc6ab
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GPG key ID: B5690EEEBB952194
4 changed files with 27 additions and 6 deletions

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@ -21,3 +21,5 @@ The current raw motion values. This is a 3 `int16_t` array:
- [0] : X
- [1] : Y
- [2] : Z
The three motion values are in units of "binary milli-g", where 1g is represented by a value of 1024.

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@ -53,9 +53,9 @@ void Motion::Refresh() {
lv_label_set_text_fmt(labelStep, "Steps %lu", motionController.NbSteps());
lv_label_set_text_fmt(label,
"X #FF0000 %d# Y #00B000 %d# Z #FFFF00 %d#",
motionController.X() / 0x10,
motionController.Y() / 0x10,
motionController.Z() / 0x10);
"X #FF0000 %d# Y #00B000 %d# Z #FFFF00 %d# mg",
motionController.X(),
motionController.Y(),
motionController.Z());
lv_obj_align(label, nullptr, LV_ALIGN_IN_TOP_MID, 0, 10);
}

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@ -22,6 +22,16 @@ namespace {
void user_delay(uint32_t period_us, void* /*intf_ptr*/) {
nrf_delay_us(period_us);
}
// Scale factors to convert accelerometer counts to milli-g
// from datasheet: https://files.pine64.org/doc/datasheet/pinetime/BST-BMA421-FL000.pdf
// The array index to use is stored in accel_conf.range
constexpr int16_t accelScaleFactors[] = {
[BMA4_ACCEL_RANGE_2G] = 1024, // LSB/g +/- 2g range
[BMA4_ACCEL_RANGE_4G] = 512, // LSB/g +/- 4g range
[BMA4_ACCEL_RANGE_8G] = 256, // LSB/g +/- 8g range
[BMA4_ACCEL_RANGE_16G] = 128 // LSB/g +/- 16g range
};
}
Bma421::Bma421(TwiMaster& twiMaster, uint8_t twiAddress) : twiMaster {twiMaster}, deviceAddress {twiAddress} {
@ -74,7 +84,6 @@ void Bma421::Init() {
if (ret != BMA4_OK)
return;
struct bma4_accel_config accel_conf;
accel_conf.odr = BMA4_OUTPUT_DATA_RATE_100HZ;
accel_conf.range = BMA4_ACCEL_RANGE_2G;
accel_conf.bandwidth = BMA4_ACCEL_NORMAL_AVG4;
@ -102,8 +111,17 @@ void Bma421::Write(uint8_t registerAddress, const uint8_t* data, size_t size) {
Bma421::Values Bma421::Process() {
if (not isOk)
return {};
struct bma4_accel rawData;
struct bma4_accel data;
bma4_read_accel_xyz(&data, &bma);
bma4_read_accel_xyz(&rawData, &bma);
// Scale the measured ADC counts to units of 'binary milli-g'
// where 1g = 1024 'binary milli-g' units.
// See https://github.com/InfiniTimeOrg/InfiniTime/pull/1950 for
// discussion of why we opted for scaling to 1024 rather than 1000.
data.x = 1024 * rawData.x / accelScaleFactors[accel_conf.range];
data.y = 1024 * rawData.y / accelScaleFactors[accel_conf.range];
data.z = 1024 * rawData.z / accelScaleFactors[accel_conf.range];
uint32_t steps = 0;
bma423_step_counter_output(&steps, &bma);

View file

@ -41,6 +41,7 @@ namespace Pinetime {
TwiMaster& twiMaster;
uint8_t deviceAddress = 0x18;
struct bma4_dev bma;
struct bma4_accel_config accel_conf; // Store the device configuration for later reference.
bool isOk = false;
bool isResetOk = false;
DeviceTypes deviceType = DeviceTypes::Unknown;