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Fix interpretation of device timestamps #736

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merged 1 commit into from
Aug 9, 2024
Merged

Fix interpretation of device timestamps #736

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23 changes: 14 additions & 9 deletions src/board_controller/openbci/galea_v4.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -408,10 +408,12 @@ void GaleaV4::read_thread ()
// calc delta between PC timestamp and device timestamp in last 10 packages,
// use this delta later on to assign timestamps
double pc_timestamp = get_timestamp ();
double timestamp_last_package = 0.0;
memcpy (&timestamp_last_package, b + 88 + offset_last_package, 8);
timestamp_last_package /= 1000; // from ms to seconds
double time_delta = pc_timestamp - timestamp_last_package;
unsigned long long timestamp_last_package = 0.0;
memcpy (&timestamp_last_package, b + 88 + offset_last_package,
sizeof (unsigned long long)); // microseconds
double timestamp_last_package_converted =
static_cast<double> (timestamp_last_package) / 1000000.0; // convert to seconds
double time_delta = pc_timestamp - timestamp_last_package_converted;
time_buffer.add_data (&time_delta);
int num_time_deltas = (int)time_buffer.get_current_data (10, latest_times);
time_delta = 0.0;
Expand Down Expand Up @@ -447,15 +449,18 @@ void GaleaV4::read_thread ()
exg_package[i - 3] =
exg_scale * (double)cast_24bit_to_int32 (b + offset + 5 + 3 * (i - 4));
}
double timestamp_device = 0.0;
memcpy (&timestamp_device, b + 88 + offset, 8);
timestamp_device /= 1000; // from ms to seconds
unsigned long long timestamp_device = 0.0;
memcpy (&timestamp_device, b + 88 + offset,
sizeof (unsigned long long)); // reports microseconds

double timestamp_device_converted = static_cast<double> (timestamp_device);
timestamp_device_converted /= 1000000.0; // convert to seconds

exg_package[board_descr["default"]["timestamp_channel"].get<int> ()] =
timestamp_device + time_delta - half_rtt;
timestamp_device_converted + time_delta - half_rtt;
exg_package[board_descr["default"]["other_channels"][0].get<int> ()] = pc_timestamp;
exg_package[board_descr["default"]["other_channels"][1].get<int> ()] =
timestamp_device;
timestamp_device_converted;
push_package (exg_package);

// aux, 5 times smaller sampling rate
Expand Down
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