I've been playing around with the multi-central central/peripheral examples and I thought I would modify the peripheral to instead use a service I had written for another application, but simply notifies with one byte as the example does.
Not really understanding a great deal of the configuration finer points from the peripheral example, I copied over the service and characteristic initialisation from main.c and used it in place of my original in core_service.c where my service and service functions reside.
It all works fine, with the timer triggering a TWI read which then has a callback to get the data and pass it to the function that updates the characteristic. When it hits the sd_ble_gatts_hvx() it errors out. For some reason it won't send the error over UART, so I debugged to read the error code (0x00003003).
I understand this error is something to do with attribute handles, but as far as I can see it's all set up correctly and should be working fine.
Below is a copy of the service initialisation and the characteristic update function.
void core_service_init(void)
{
uint32_t err_code;
ble_uuid_t service_uuid;
ble_gatts_char_md_t char_md;
ble_gatts_attr_t attr;
ble_gatts_attr_md_t attr_md;
ble_gatts_attr_md_t cccd_md;
ble_gatts_attr_md_t char_ud_md;
uint16_t svc_test;
static uint8_t peripheral_data;
static uint8_t peripheral_ud[] = "Modifiable multilink_peripheral Data";
ble_uuid128_t base_uuid = BLE_UUID_CORE_BASE_UUID;
err_code = sd_ble_uuid_vs_add(&base_uuid, &service_uuid.type);
APP_ERROR_CHECK(err_code);
service_uuid.uuid = BLE_UUID_CORE_SERVICE;
err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,
&service_uuid,
&m_core_service.service_handle);
APP_ERROR_CHECK(err_code);
// characteristic setup //
service_uuid.uuid = BLE_UUID_RH_CHAR_UUID;
memset(&attr, 0, sizeof(ble_gatts_attr_t));
attr.p_uuid = &service_uuid;
attr.p_attr_md = &attr_md;
attr.max_len = 1;
attr.p_value = &peripheral_data;
attr.init_len = sizeof(peripheral_data);
memset(&attr_md, 0, sizeof(ble_gatts_attr_md_t));
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM(&attr_md.write_perm);
attr_md.vloc = BLE_GATTS_VLOC_STACK;
attr_md.vlen = 0;
memset(&cccd_md, 0, sizeof(ble_gatts_attr_md_t));
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
BLE_GAP_CONN_SEC_MODE_SET_ENC_NO_MITM(&cccd_md.write_perm);
cccd_md.vloc = BLE_GATTS_VLOC_STACK;
memset(&char_md, 0, sizeof(ble_gatts_char_md_t));
char_md.p_cccd_md = &cccd_md;
char_md.char_props.notify = 1;
char_md.char_props.indicate = 1;
char_md.char_props.read = 1;
char_md.char_props.write = 1;
char_md.char_ext_props.wr_aux = 1;
char_md.p_user_desc_md = &char_ud_md;
char_md.p_char_user_desc = peripheral_ud;
char_md.char_user_desc_size = (uint8_t)strlen((char *)peripheral_ud);
char_md.char_user_desc_max_size = (uint8_t)strlen((char *)peripheral_ud);
memset(&char_ud_md, 0, sizeof(ble_gatts_attr_md_t));
char_ud_md.vloc = BLE_GATTS_VLOC_STACK;
char_ud_md.vlen = 1;
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&char_ud_md.read_perm);
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&char_ud_md.write_perm);
err_code = sd_ble_gatts_characteristic_add(BLE_GATT_HANDLE_INVALID,
&char_md,
&attr,
&m_core_service.rh_handles);
// initialise timer
timer_init();
}
The characteristic update/notify function
static void sensor_rh_characteristic_update(uint32_t * p_char_value)
{
uint32_t err_code;
// Update characteristic value
if (m_core_service.conn_handle != BLE_CONN_HANDLE_INVALID)
{
uint16_t len = 1;
ble_gatts_hvx_params_t hvx_params;
memset(&hvx_params, 0, sizeof(hvx_params));
hvx_params.handle = m_core_service.rh_handles.value_handle;
hvx_params.type = BLE_GATT_HVX_NOTIFICATION;
hvx_params.offset = 0;
hvx_params.p_len = &len;
hvx_params.p_data = (uint8_t*)p_char_value; //characteristic_value;
err_code = sd_ble_gatts_hvx(m_core_service.conn_handle, &hvx_params);
APP_ERROR_CHECK(err_code);
}
}
