Central and Peripheral: BLE_NUS in parallel with BLE_HRS_C

[Andrea Aizza]

Hi, 

would like to run several (8) BLE_HRS_C in parallel to one BLE_NUS on a nRF5. Can that work?

In general, is it there any sample code showing how to implement peripheral role (BLE_NUS)  in parallel with central role (BLE_HRS_C)? 

The problem I am encountering (on nRF52840 DK, nRF5_SDK_15.2.0_9412b96) is with BLE_NUS, when sending data (ble_nus_data_send()) it hangs in ble_link_ctx_manager.c:70:

```

70 if (conn_id >= p_link_ctx_storage->max_links_cnt)

71 {
72 return NRF_ERROR_NO_MEM;
73 }

```

as the connection id of the peripheral (BLE_NUS) conn_id==8 and there is only 1 BLE_LINK_CTX_MANAGER_DEF defined (in ble_nus.c), therefore p_link_ctx_storage->max_links_cnt==1. What is the right way to solve this?

Thanks,

Andrea

[Andrea Aizza]

Yes, sure. The below is sufficient. But I did not wanna modify SDK files. Just wondering what is the right way to do it. 

diff --git a/components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c b/components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c
index 2a139f4..11ae062 100644
--- a/components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c
+++ b/components/ble/ble_link_ctx_manager/ble_link_ctx_manager.c
@@ -67,10 +67,10 @@ ret_code_t blcm_link_ctx_get(blcm_link_ctx_storage_t const * const p_link_ctx_st
         return NRF_ERROR_NOT_FOUND;
     }
 
-    if (conn_id >= p_link_ctx_storage->max_links_cnt)
-    {
-        return NRF_ERROR_NO_MEM;
-    }
+    //if (conn_id >= p_link_ctx_storage->max_links_cnt)^M
+    //{^M
+    //    return NRF_ERROR_NO_MEM;^M
+    //}^M
 
     *pp_ctx_data = (void *) ((uint8_t *) p_link_ctx_storage->p_ctx_data_pool + 
                              conn_id * p_link_ctx_storage->link_ctx_size);

[Vidar Berg]

With the current implementation, the more correct way would probably be to use the link context manager for all links and not just the NUS connection. But I think it's ok to modify the SDK module as you did.

[goldwake]

This issue is a pain for me as well. Having central and peripheral connections doesn't work very well with the link ctx mgr. It's a bit wasteful having  sizeof(ble_nus_client_context_t) * num_central_connections unused bytes allocated for the ctx manager. Especially when you've got a lot of connection which use up a lot ofRAM already. 

I know it's not ideal but I use my own blcm_link_ctx_get function to handle this

static uint32_t get_link_ctx(ble_gm_device_t * p_gm_device, uint16_t conn_handle, ble_gm_device_client_context_t ** const p_client)
{
    if (p_client == NULL)
    {
        return NRF_ERROR_NULL;
    }
    else
    {
        *p_client = NULL;
    }
    
    VERIFY_PARAM_NOT_NULL(p_gm_device->p_link_ctx_storage);
    VERIFY_PARAM_NOT_NULL(p_gm_device->p_link_ctx_storage->p_ctx_data_pool);
    VERIFY_TRUE((p_gm_device->p_link_ctx_storage->link_ctx_size % BYTES_PER_WORD) == 0, NRF_ERROR_INVALID_PARAM);
    
    uint16_t link_ctx_index = 0;
    for(link_ctx_index = 0; link_ctx_index < p_gm_device->p_link_ctx_storage->max_links_cnt; link_ctx_index++)
    {
        if(p_gm_device->conn_handles[link_ctx_index] == conn_handle )
        {
            *p_client = (void *) ((uint8_t *) p_gm_device->p_link_ctx_storage->p_ctx_data_pool + 
                             link_ctx_index * p_gm_device->p_link_ctx_storage->link_ctx_size);
            return NRF_SUCCESS;
        }
    }
    return NRF_ERROR_NOT_FOUND;
    
}