Can someone explain the proper way to use the tx_buffer_process function present in many of the service libraries.
It seems this function is used to handle requests to read/write the ble service, but I'm not entirely clear on how it's being used. It seems to me that the cccd_configure() function for example is adding a write command to the buffer and then calling tx_buffer process.
I've modified this function to write to the characteristic value instead of the CCCD, but when I call tx_buffer_process, I get an NRF_BUSY error. I see that the tx_buffer_process function will not advance the m_tx_index in this case, but I don't see anywhere in the sample where the tx_buffer_process is called again to keep attempting to send out any pending messages.
static uint32_t value_set(uint16_t conn_handle, uint16_t handle_value)
{
tx_message_t * p_msg;
p_msg = &m_tx_buffer[m_tx_insert_index++]; /* Set pointer to buffer tail */
m_tx_insert_index &= TX_BUFFER_MASK; /* Increment buffer tail */
/* Connection handle + message type (R/W) */
p_msg->conn_handle = conn_handle; /* Set connection handle for message */
p_msg->type = WRITE_REQ; /* Message type = write */
/* Setup data to be written */
p_msg->req.write_req.gattc_value[0] = 0xAF;
/* Write Parameters */
p_msg->req.write_req.gattc_params.write_op = BLE_GATT_OP_WRITE_REQ;
p_msg->req.write_req.gattc_params.handle = handle_value; /* Writing to characteristic value */
p_msg->req.write_req.gattc_params.offset = 0;
p_msg->req.write_req.gattc_params.len = 1; /* Length of value */
p_msg->req.write_req.gattc_params.p_value = p_msg->req.write_req.gattc_value; /* Pointer to Write Data */
return tx_buffer_process(); /* Send the message */
}
tx_buffer_process from ble_bas_c.c
/**@brief Function for passing any pending request from the buffer to the stack.
*/
static void tx_buffer_process(void)
{
if (m_tx_index != m_tx_insert_index)
{
uint32_t err_code;
if (m_tx_buffer[m_tx_index].type == READ_REQ)
{
err_code = sd_ble_gattc_read(m_tx_buffer[m_tx_index].conn_handle,
m_tx_buffer[m_tx_index].req.read_handle,
0);
}
else
{
err_code = sd_ble_gattc_write(m_tx_buffer[m_tx_index].conn_handle,
&m_tx_buffer[m_tx_index].req.write_req.gattc_params);
}
if (err_code == NRF_SUCCESS)
{
LOG("[HRS_C]: SD Read/Write API returns Success..\r\n");
m_tx_index++;
m_tx_index &= TX_BUFFER_MASK;
}
else
{
LOG("[HRS_C]: SD Read/Write API returns error. This message sending will be "
"attempted again..\r\n");
}
}
}
