extmod/modbluetooth: Allow config of scan interval/window. #5190
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extmod/modbluetooth_nimble.c
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| .window = BLE_GAP_SCAN_SLOW_WINDOW1, | ||
| uint16_t interval = BLE_GAP_SCAN_SLOW_INTERVAL1; | ||
| uint16_t window = BLE_GAP_SCAN_SLOW_WINDOW1; | ||
| if (interval_ms > 0) { |
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No need to check this, just assume valid (default at least) values are passed in.
| .filter_policy = BLE_HCI_CONN_FILT_NO_WL, | ||
| .limited = 0, | ||
| .passive = 0, | ||
| .passive = 1, // TODO: Handle BLE_HCI_ADV_RPT_EVTYPE_SCAN_RSP in gap_scan_cb above. |
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Why does this need to be changed?
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It was wrong before, because we're not handling the scan response event. Now that this change allows us to scan much faster, no point spamming the radio with active scans if we're going to ignore them.
I plan to add an active=True arg to scan() later when implementing active scans.
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Thanks, have made the suggested changes. |
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Looking at this again I see that the scanning intervals are in millisecond units. But this doesn't give enough resolution (in integers) to match what's possible with BLE. BLE scanning (and advertising) uses units of 625us, and so allows fractional millisecond values. So I think it'd be good to change the units of these interval parameters to microseconds. (But keep the scan duration in milliseconds, which is not related to the BLE spec.) |
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This adds two additional optional kwargs to `gap_scan()`: - `interval_us`: How long between scans. - `window_us`: How long to scan for during a scan. The default with NimBLE is a 11.25ms window with a 1.28s interval. Changing these parameters is important for detecting low-frequency advertisements (e.g. beacons). Note: these params are in microseconds, not milliseconds in order to allow the 625us granularity offered by the spec.
This is to more accurately match the BLE spec, where intervals are configured in units of channel hop time (625us). When it was specified in ms, not all "valid" intervals were able to be specified. Now that we're also allowing configuration of scan interval, this commit updates advertising to match.
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samd: diagnose out of range I2C frequency
This adds two additional optional kwargs to
gap_scan():interval_ms: How long between scans.window_ms: How long to scan for during a scan.The default with NimBLE is a 11.25ms window with a 1.28s interval.
Changing these parameters is important for detecting low-frequency
advertisements (e.g. beacons).