extmod/modbluetooth: Use us instead of ms for advertising interval.

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.

1 files changed, 4 insertions, 10 deletions

diff --git a/extmod/modbluetooth_nimble.c b/extmod/modbluetooth_nimble.c
index 727894f86..8805d4100 100644
--- a/extmod/modbluetooth_nimble.c
+++ b/extmod/modbluetooth_nimble.c
@@ -341,7 +341,7 @@ void mp_bluetooth_get_device_addr(uint8_t *addr) {
     #endif
 }
 
-int mp_bluetooth_gap_advertise_start(bool connectable, uint16_t interval_ms, const uint8_t *adv_data, size_t adv_data_len, const uint8_t *sr_data, size_t sr_data_len) {
+int mp_bluetooth_gap_advertise_start(bool connectable, int32_t interval_us, const uint8_t *adv_data, size_t adv_data_len, const uint8_t *sr_data, size_t sr_data_len) {
     int ret;
 
     mp_bluetooth_gap_advertise_stop();
@@ -360,18 +360,12 @@ int mp_bluetooth_gap_advertise_start(bool connectable, uint16_t interval_ms, con
         }
     }
 
-    // Convert from 1ms to 0.625ms units.
-    interval_ms = interval_ms * 8 / 5;
-    if (interval_ms < 0x20 || interval_ms > 0x4000) {
-        return MP_EINVAL;
-    }
-
     struct ble_gap_adv_params adv_params = {
         .conn_mode = connectable ? BLE_GAP_CONN_MODE_UND : BLE_GAP_CONN_MODE_NON,
         .disc_mode = BLE_GAP_DISC_MODE_GEN,
-        .itvl_min = interval_ms,
-        .itvl_max = interval_ms,
-        .channel_map = 7, // all 3 channels
+        .itvl_min = interval_us / BLE_HCI_ADV_ITVL, // convert to 625us units.
+        .itvl_max = interval_us / BLE_HCI_ADV_ITVL,
+        .channel_map = 7, // all 3 channels.
     };
 
     ret = ble_gap_adv_start(BLE_OWN_ADDR_PUBLIC, NULL, BLE_HS_FOREVER, &adv_params, gap_event_cb, NULL);