How to correctly set channel map of next connection?

[Gregor Bader]

I'm using s130_nrf51_2.0.0-4.alpha as central and do some testing with channel map. I set the channel map before I'm trying to connect to a peripheral with:

  ble_opt_t opt;
  memset(&opt, 0, sizeof(opt));
  opt.gap_opt.ch_map.ch_map[0] = 0xFF;
  opt.gap_opt.ch_map.ch_map[1] = 0x0F;
  err_code = sd_ble_opt_set(BLE_GAP_OPT_CH_MAP, &opt);
  APP_ERROR_CHECK(err_code);

  // Initiate connection.
  err_code = sd_ble_gap_connect(peer_addr,
                                &m_scan_param,
                                &conn_params);

But when I check the current active channel map during the connection, I get the default channel map!

  ble_opt_t opt;
  memset(&opt, 0, sizeof(opt));
  opt.gap_opt.ch_map.conn_handle = m_conn_handle_central;
  sd_ble_opt_get(BLE_GAP_OPT_CH_MAP, &opt);
  APP_LOG("ChMap %02X %02X %02X %02X %02X\r\n",
    opt.gap_opt.ch_map.ch_map[0], opt.gap_opt.ch_map.ch_map[1], opt.gap_opt.ch_map.ch_map[2],
    opt.gap_opt.ch_map.ch_map[3], opt.gap_opt.ch_map.ch_map[4]);

Output:

ChMap FF FF FF FF 1F

[Ole Bauck]

Setting the channel map may take some time, see here. Try to call sd_ble_opt_get(...) at a later point in time.

[Ole Bauck]

I was just using the connection parameter update request event to read the channel map since I knew this happened 5 seconds after the connection. The channel map have been updated some time in between. Feel free to start a timer (e.g. app_timer) on connection and read the channel map sooner to see when it changes.