Can nou update Characteristic value

[OLEG_T]

I've created read onle characteristic called "log". In  main.c i try to update it by calling : ulogd_characteristic_update(&m_ulog_service,Log_Data_arr)

But nothing happens, can you solve my issue (p.s. I am new to ble)

void ulogd_characteristic_update(ble_ulog_service_t *p_ulog_service, int32_t *log_data)
{
if (p_ulog_service->conn_handle != BLE_CONN_HANDLE_INVALID)
{
uint16_t len = 10;
ble_gatts_hvx_params_t hvx_params;
memset(&hvx_params, 0, sizeof(hvx_params));

hvx_params.handle = p_ulog_service->ulog_char_handles.value_handle;
hvx_params.type = BLE_GATT_HVX_NOTIFICATION;
hvx_params.offset = 0;
hvx_params.p_len = &len;
hvx_params.p_data = log_data;

sd_ble_gatts_hvx(p_ulog_service->conn_handle, &hvx_params);
}

}

[OLEG_T]

log_service.c

#include <string.h>

#include "nrf_log.h"
#include "log_service.h"

static const uint8_t ULOGCharName[] = "Log";
static const uint8_t ULOGTIMECharName[] = "Time";

static void on_connect(ble_ulog_service_t * p_ulog_service, ble_evt_t const * p_ble_evt)
{
p_ulog_service->conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
}

static void on_disconnect(ble_ulog_service_t * p_ulog_service, ble_evt_t const * p_ble_evt)
{
UNUSED_PARAMETER(p_ble_evt);
p_ulog_service->conn_handle = BLE_CONN_HANDLE_INVALID;
}

static void on_write(ble_ulog_service_t * p_ulog_service, ble_evt_t const * p_ble_evt)
{
ble_gatts_evt_write_t const * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;

/* if ( (p_evt_write->handle == p_ulog_service->ulog_char_handles.value_handle)
&& (p_evt_write->len == 1)
&& (p_ulog_service->ulog_write_handler != NULL))
{
p_ulog_service->ulog_write_handler(p_ble_evt->evt.gap_evt.conn_handle, p_ulog_service, p_evt_write->data[0]);
}
*/
if ( (p_evt_write->handle == p_ulog_service->ulogtime_char_handles.value_handle)
&& (p_evt_write->len == 5)
&& (p_ulog_service->ulogtime_write_handler != NULL))
{
p_ulog_service->ulogtime_write_handler(p_ble_evt->evt.gap_evt.conn_handle, p_ulog_service, p_evt_write->data);
}
}

static uint32_t ulog_char_add(ble_ulog_service_t * p_ulog_service)
{
ble_gatts_char_md_t char_md;
ble_gatts_attr_t attr_char_value;
ble_gatts_attr_md_t attr_md;
ble_uuid_t ble_uuid;

memset(&char_md, 0, sizeof(char_md));
memset(&attr_md, 0, sizeof(attr_md));
memset(&attr_char_value, 0, sizeof(attr_char_value));

char_md.char_props.read = 1;
//char_md.char_props.write = 1;
char_md.p_char_user_desc = ULOGCharName ;
char_md.char_user_desc_size = sizeof(ULOGCharName);
char_md.char_user_desc_max_size = sizeof(ULOGCharName);
char_md.p_char_pf = NULL;
char_md.p_user_desc_md = NULL;
char_md.p_cccd_md = NULL;
char_md.p_sccd_md = NULL;
ble_uuid.type = p_ulog_service->uuid_type;
ble_uuid.uuid = BLE_UUID_ULOG_CHAR_UUID ;

BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
// Attribute Metadata settings
attr_md.vloc = BLE_GATTS_VLOC_STACK;
attr_md.rd_auth = 0;
attr_md.wr_auth = 0;
attr_md.vlen = 0;
// Attribute Value settings
attr_char_value.p_uuid = &ble_uuid;
attr_char_value.p_attr_md = &attr_md;
attr_char_value.init_len = 10;
attr_char_value.init_offs = 0;
attr_char_value.max_len = 10;
uint8_t value[10] = {0xAA,0xBB,0xCC,0xDD,0xEE,0xFF,0x11,0x22,0x33,0x44};
attr_char_value.p_value = value;

return sd_ble_gatts_characteristic_add(p_ulog_service->service_handle, &char_md,
&attr_char_value,
&p_ulog_service->ulog_char_handles);
}

static uint32_t ulogtime_char_add(ble_ulog_service_t * p_ulog_service)
{
ble_gatts_char_md_t char_md;
ble_gatts_attr_t attr_char_value;
ble_gatts_attr_md_t attr_md;
ble_uuid_t ble_uuid;

memset(&char_md, 0, sizeof(char_md));
memset(&attr_md, 0, sizeof(attr_md));
memset(&attr_char_value, 0, sizeof(attr_char_value));

char_md.char_props.read = 1;
char_md.char_props.write = 1;
char_md.p_char_user_desc = ULOGTIMECharName;
char_md.char_user_desc_size = sizeof(ULOGTIMECharName);
char_md.char_user_desc_max_size = sizeof(ULOGTIMECharName);
char_md.p_char_pf = NULL;
char_md.p_user_desc_md = NULL;
char_md.p_cccd_md = NULL;
char_md.p_sccd_md = NULL;
ble_uuid.type = p_ulog_service->uuid_type;
ble_uuid.uuid = BLE_UUID_ULOGTIME_CHAR_UUID ;
// Set permissions on the Characteristic value
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);
BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
// Attribute Metadata settings
attr_md.vloc = BLE_GATTS_VLOC_STACK;
attr_md.rd_auth = 0;
attr_md.wr_auth = 0;
attr_md.vlen = 0;
// Attribute Value settings
attr_char_value.p_uuid = &ble_uuid;
attr_char_value.p_attr_md = &attr_md;
attr_char_value.init_len = 5;
attr_char_value.init_offs = 0;
attr_char_value.max_len = 5;
uint8_t value[5] = {0x20,0x01,0x29,0x18,0x30};
attr_char_value.p_value = value;

return sd_ble_gatts_characteristic_add(p_ulog_service->service_handle, &char_md,
&attr_char_value,
&p_ulog_service->ulogtime_char_handles);
}

uint32_t ble_ulog_service_init(ble_ulog_service_t * p_ulog_service, const ble_ulog_service_init_t * p_ulog_service_init)
{
uint32_t err_code;
ble_uuid_t ble_uuid;
// Initialize service structure
p_ulog_service->conn_handle = BLE_CONN_HANDLE_INVALID;
p_ulog_service->ulogtime_write_handler = p_ulog_service_init->ulogtime_write_handler;
// Add service UUID
ble_uuid128_t base_uuid = {BLE_UUID_ULOG_SERVICE_BASE_UUID};
err_code = sd_ble_uuid_vs_add(&base_uuid, &p_ulog_service->uuid_type);
if (err_code != NRF_SUCCESS)
{
return err_code;
}
// Set up the UUID for the service (base + service-specific)
ble_uuid.type = p_ulog_service->uuid_type;
ble_uuid.uuid = BLE_UUID_ULOG_SERVICE_UUID;
// Set up and add the service
err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY, &ble_uuid, &p_ulog_service->service_handle);
if (err_code != NRF_SUCCESS)
{
return err_code;
}

err_code = ulog_char_add(p_ulog_service);
if (err_code != NRF_SUCCESS)
{
return err_code;
}

err_code = ulogtime_char_add(p_ulog_service);
if (err_code != NRF_SUCCESS)
{
return err_code;
}

return NRF_SUCCESS;
}

void ble_ulog_service_on_ble_evt(ble_evt_t const * p_ble_evt, void * p_context)
{
ble_ulog_service_t * p_ulog_service = (ble_ulog_service_t *)p_context;
switch (p_ble_evt->header.evt_id)
{
case BLE_GAP_EVT_CONNECTED:
on_connect(p_ulog_service, p_ble_evt);
break;
case BLE_GATTS_EVT_WRITE:
on_write(p_ulog_service, p_ble_evt);
break;
case BLE_GAP_EVT_DISCONNECTED:
on_disconnect(p_ulog_service, p_ble_evt);
break;
default:
// No implementation needed.
break;
}
}

void ulogd_characteristic_update(ble_ulog_service_t *p_ulog_service, int32_t *log_data)
{
if (p_ulog_service->conn_handle != BLE_CONN_HANDLE_INVALID)
{
uint16_t len = 10;
ble_gatts_hvx_params_t hvx_params;
memset(&hvx_params, 0, sizeof(hvx_params));

hvx_params.handle = p_ulog_service->ulog_char_handles.value_handle;
hvx_params.type = BLE_GATT_HVX_NOTIFICATION;
hvx_params.offset = 0;
hvx_params.p_len = &len;
hvx_params.p_data = log_data;

sd_ble_gatts_hvx(p_ulog_service->conn_handle, &hvx_params);
}

}