Hi!
I am working on a customer project where up to 20 BLE peripherals are connected to a single central device. The code of the central is based on the Multi-NUS sample from this Nordic-Blog-Post and has been updated to NCS Version v2.0.0.
The NUS client has been optimized for data throughput. Therefore, the following additions have been made to the nus_client.c file:
/* Heap region to hold TX context */
struct tx_ctx_t {
struct bt_nus_client *nus_c;
const uint8_t *data;
uint32_t length;
};
K_HEAP_DEFINE(tx_ctx_heap, CONFIG_BT_MAX_CONN * CONFIG_BT_CONN_TX_MAX * sizeof(struct tx_ctx_t));
static void on_sent_wo_rsp(struct bt_conn *conn, void *user_data)
{
// get tx context from user data
struct tx_ctx_t *context = (struct tx_ctx_t*) user_data;
// make a copy of volatile data that is required by the callback
struct bt_nus_client *nus_c = context->nus_c;
const void *data = context->data;
uint16_t length = (uint16_t) context->length;
// release allocated tx context
k_heap_free(&tx_ctx_heap, user_data);
if (nus_c->cb.sent) {
nus_c->cb.sent(nus_c, 0, data, length);
}
}
int bt_nus_client_send(struct bt_nus_client *nus_c, const uint8_t *data, uint16_t len)
{
int err;
if (!nus_c->conn) {
return -ENOTCONN;
}
// allocate TX context
struct tx_ctx_t* context = k_heap_alloc(&tx_ctx_heap, sizeof(struct tx_ctx_t), K_NO_WAIT);
if (context == NULL) {
LOG_ERR("TX context allocation failed");
return -ENOMEM;
}
context->nus_c = nus_c;
context->data = data;
context->length = len;
// throughput optimized GATT write request
err = bt_gatt_write_without_response_cb(nus_c->conn, nus_c->handles.rx, data, len, false, on_sent_wo_rsp, context);
if (err) {
// release allocated tx context
k_heap_free(&tx_ctx_heap, context);
}
return err;
}
Here is my project Kconfig configuration file:
# # Copyright (c) 2018 Nordic Semiconductor # # SPDX-License-Identifier: LicenseRef-Nordic-5-Clause # # C++ Support CONFIG_CPLUSPLUS=y CONFIG_NEWLIB_LIBC=y CONFIG_STD_CPP17=y #CONFIG_LIB_CPLUSPLUS=y # Configure Serial driver (additional configuration is done in overlay-<usb/uart>.conf) CONFIG_STDOUT_CONSOLE=y CONFIG_SERIAL=y CONFIG_UART_INTERRUPT_DRIVEN=y CONFIG_UART_LINE_CTRL=y # Enable the BLE stack with GATT Client configuration CONFIG_BT=y CONFIG_BT_CENTRAL=y CONFIG_BT_SMP=y CONFIG_BT_GATT_CLIENT=y CONFIG_BT_MAX_CONN=20 CONFIG_BT_MAX_PAIRED=20 CONFIG_BT_CONN_CTX=y # Advanced BLE configuration CONFIG_BT_CTLR_ADVANCED_FEATURES=y CONFIG_BT_CTLR_CONN_RSSI=y CONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL=y CONFIG_BT_USER_PHY_UPDATE=y CONFIG_BT_CTLR_PHY_CODED=y # Enable the BLE modules from NCS #CONFIG_BT_LOG_LEVEL_DBG=y CONFIG_BT_NUS=y CONFIG_BT_SCAN=y CONFIG_BT_SCAN_FILTER_ENABLE=y CONFIG_BT_SCAN_UUID_CNT=1 CONFIG_BT_GATT_DM=y CONFIG_HEAP_MEM_POOL_SIZE=16384 # BLE Scanner configuration CONFIG_BT_SCAN_ADDRESS_CNT=20 CONFIG_BT_SCAN_NAME_CNT=1 # MTU configuration taken from throughput example (adapted) CONFIG_BT_BUF_ACL_RX_SIZE=251 CONFIG_BT_BUF_ACL_TX_SIZE=251 CONFIG_BT_BUF_ACL_TX_COUNT=40 CONFIG_BT_L2CAP_TX_BUF_COUNT=40 CONFIG_BT_ATT_PREPARE_COUNT=2 CONFIG_BT_L2CAP_TX_MTU=247 CONFIG_BT_CTLR_RX_BUFFERS=2 CONFIG_BT_CTLR_DATA_LENGTH_MAX=251 # This example requires more workqueue stack CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=4096 CONFIG_BT_RX_STACK_SIZE=4096 # Enable bonding CONFIG_BT_SETTINGS=y CONFIG_FLASH=y CONFIG_FLASH_PAGE_LAYOUT=y CONFIG_FLASH_MAP=y CONFIG_NVS=y CONFIG_SETTINGS=y # Config logger CONFIG_LOG=y CONFIG_USE_SEGGER_RTT=y CONFIG_LOG_BACKEND_RTT=y CONFIG_LOG_BACKEND_UART=n # App specific config CONFIG_BASE64=y # Bootloader CONFIG_BOOTLOADER_MCUBOOT=y
The central throws a Zephyr Kernel oops error, when data is sent to and response is received from more than 10 peripherals.
[00:02:10.709,259] [1;31m<err> os: r0/a1: 0x00000003 r1/a2: 0x00000000 r2/a3: 0x00000000[0m [00:02:10.709,289] [1;31m<err> os: r3/a4: 0x20019646 r12/ip: 0x00000000 r14/lr: 0x000351bf[0m [00:02:10.709,320] [1;31m<err> os: xpsr: 0x61000000[0m [00:02:10.709,320] [1;31m<err> os: Faulting instruction address (r15/pc): 0x000351ca[0m [00:02:10.709,350] [1;31m<err> os: >>> ZEPHYR FATAL ERROR 3: Kernel oops on CPU 0[0m [00:02:10.709,381] [1;31m<err> os: Current thread: 0x20002c98 (BT RX)[0m [00:02:10.906,616] [1;31m<err> fatal_error: Resetting system[0m
Resolving the PC shows that the error is a HCI_CMD_TIMEOUT in function bt_hci_cmd_send_sync of the hci_core.c file.
err = k_sem_take(&sync_sem, HCI_CMD_TIMEOUT); BT_ASSERT_MSG(err == 0, "k_sem_take failed with err %d", err);
I think the problem is related to a deadlock of the BLE driver. Is there something wrong with my code or configuration?
Best regards,
Thomas
