URAT Data Transmission in DFU mode

[RAJVARDHAN]

nrf52840 17.1.0 s140 SDK :- examples/dfu/secure_bootloader/pca10056_s140_ble_debug

We are using the secure bootloader with BLE debug and have combined BLE and UART for the DFU bootloader. However, while performing DFU over-the-air (FOTA) from a mobile device, I am trying to send data to print BLE packets using UART. I am able to send only one packet; after that, the transmission stops, and I cannot send additional data. For reference, see the log below.

We call the function from nrf_dfu_ble.c:
static void on_write(ble_dfu_t * p_dfu, ble_evt_t const * p_ble_evt)
{
// Existing code

nrf_drv_uart_tx(&m_uart, data, length);

// Existing code
}

Note: We need to achieve this using only in this SDK version pca10056_s140_ble_debug.

<info> app: Inside main
<debug> app: In nrf_bootloader_init
<debug> nrf_dfu_settings: Calling nrf_dfu_settings_init()...
<debug> nrf_dfu_flash: Initializing nrf_fstorage_nvmc backend.
<debug> nrf_dfu_settings: Using settings page.
<debug> nrf_dfu_settings: Copying forbidden parts from backup page.
<debug> nrf_dfu_settings: Destination settings are identical to source, write not needed. Skipping.
<info> nrf_dfu_settings: Backing up settings page to address 0xFE000.
<debug> nrf_dfu_settings: Destination settings are identical to source, write not needed. Skipping.
<debug> app: Enter nrf_bootloader_fw_activate
<info> app: No firmware to activate.
<info> app: Boot validation failed. No valid app to boot.
<debug> app: DFU mode because app is not valid.
<info> nrf_bootloader_wdt: WDT is not enabled
<debug> app: in weak nrf_dfu_init_user
<debug> app: timer_stop (0x20005998)
<debug> app: timer_activate (0x20005998)
<info> app: Entering DFU mode.
<debug> app: Initializing transports (found: 2)
<debug> nrf_dfu_ble: Initializing BLE DFU transport
<debug> nrf_dfu_ble: Setting up vector table: 0x000E8000
<debug> nrf_dfu_ble: Enabling SoftDevice.
<debug> nrf_dfu_ble: Configuring BLE stack.
<debug> nrf_dfu_ble: Enabling the BLE stack.
<debug> nrf_dfu_ble: No advertising name found
<debug> nrf_dfu_ble: Using default advertising name
<debug> nrf_dfu_ble: Advertising...
<debug> nrf_dfu_ble: BLE DFU transport initialized.
<debug> nrf_dfu_serial_uart: serial_dfu_transport_init()
<debug> nrf_dfu_serial_uart: serial_dfu_transport_init() completed
<info> nrf_dfu_serial_uart: Sending initial byte 0x24
<debug> nrf_dfu_flash: Initializing nrf_fstorage_sd backend.
<debug> app: Enter main loop
<debug> nrf_dfu_ble: Connected
<debug> nrf_dfu_ble: Received BLE_GAP_EVT_DATA_LENGTH_UPDATE_REQUEST.
<debug> nrf_dfu_ble: Received BLE_GAP_EVT_DATA_LENGTH_UPDATE (27, max_rx_time 328).
<debug> nrf_dfu_ble: Received BLE_GAP_EVT_CONN_PARAM_UPDATE
<debug> nrf_dfu_ble: max_conn_interval: 12
<debug> nrf_dfu_ble: min_conn_interval: 12
<debug> nrf_dfu_ble: slave_latency: 0
<debug> nrf_dfu_ble: conn_sup_timeout: 600
<debug> nrf_dfu_ble: Received BLE_GAP_EVT_CONN_PARAM_UPDATE
<debug> nrf_dfu_ble: max_conn_interval: 6
<debug> nrf_dfu_ble: min_conn_interval: 6
<debug> nrf_dfu_ble: slave_latency: 0
<debug> nrf_dfu_ble: conn_sup_timeout: 500
<debug> nrf_dfu_ble: Received BLE_GAP_EVT_CONN_PARAM_UPDATE
<debug> nrf_dfu_ble: max_conn_interval: 12
<debug> nrf_dfu_ble: min_conn_interval: 12
<debug> nrf_dfu_ble: slave_latency: 0
<debug> nrf_dfu_ble: conn_sup_timeout: 600
<debug> nrf_dfu_ble: Received BLE_GATTS_EVT_EXCHANGE_MTU_REQUEST (request: 517, reply: 247).
<debug> nrf_dfu_ble: Received BLE_GAP_EVT_DATA_LENGTH_UPDATE_REQUEST.
<debug> nrf_dfu_ble: Received BLE_GAP_EVT_DATA_LENGTH_UPDATE (251, max_rx_time 2120).
<debug> nrf_dfu_req_handler: Handle NRF_DFU_OP_OBJECT_SELECT (command)
<debug> nrf_dfu_req_handler: Request handling complete. Result: 0x1
<debug> nrf_dfu_ble: Set receipt notif
<debug> nrf_dfu_req_handler: Handle NRF_DFU_OP_RECEIPT_NOTIF_SET
<debug> nrf_dfu_req_handler: Request handling complete. Result: 0x1
<debug> app: Shutting down transports (found: 2)
<debug> nrf_dfu_req_handler: Handle NRF_DFU_OP_OBJECT_CREATE (command)
<debug> app: timer_stop (0x20005998)
<debug> app: timer_activate (0x20005998)
<debug> nrf_dfu_req_handler: Request handling complete. Result: 0x1
<debug> nrf_dfu_ble: Buffer 0x20006ED8 acquired, len 141 (244)
<debug> nrf_dfu_ble: Copying 141 bytes from p_write_evt->data to p_balloc_buf:
12 8A 01 0A 44 08 01 12|....D...
40 08 01 10 34 1A 02 80|@...4...
02 20 00 28 00 30 00 38|. .(.0.8
E0 F0 03 42 24 08 03 12|...B$...
20 60 23 74 3A 38 1B 65| `#t:8.e
2E 68 F0 F3 05 97 26 76|.h....&v
D3 61 C0 4C 00 F4 D7 E6|.a.L....
B2 44 DE EC 6C 90 75 1E|.D..l.u.
D7 48 00 52 04 08 01 12|.H.R....
00 10 00 1A 40 CA 06 15|....@...
<debug> nrf_dfu_ble: Sending 141 bytes via UART:
12 8A 01 0A 44 08 01 12|....D...
40 08 01 10 34 1A 02 80|@...4...
02 20 00 28 00 30 00 38|. .(.0.8
E0 F0 03 42 24 08 03 12|...B$...
20 60 23 74 3A 38 1B 65| `#t:8.e
2E 68 F0 F3 05 97 26 76|.h....&v
D3 61 C0 4C 00 F4 D7 E6|.a.L....
B2 44 DE EC 6C 90 75 1E|.D..l.u.
D7 48 00 52 04 08 01 12|.H.R....
00 10 00 1A 40 CA 06 15|....@...
<debug> nrf_dfu_req_handler: Handle NRF_DFU_OP_OBJECT_WRITE (command)
<debug> nrf_dfu_ble: Freeing buffer 0x20006ED8
<debug> nrf_dfu_req_handler: Request handling complete. Result: 0x1
<debug> nrf_dfu_req_handler: Handle NRF_DFU_OP_CRC_GET (command)
<debug> nrf_dfu_req_handler: Request handling complete. Result: 0x1
<debug> nrf_dfu_req_handler: Handle NRF_DFU_OP_OBJECT_EXECUTE (command)
<debug> nrf_dfu_validation: PB: Init packet data len: 64
<info> nrf_dfu_validation: Signature required. Checking signature.
<info> nrf_dfu_validation: Calculating hash (len: 64)
<info> nrf_dfu_validation: Verify signature
<info> nrf_dfu_validation: Image verified
<info> nrf_dfu_validation: Total size= 0

<debug> app: Enter nrf_dfu_cache_prepare()
<debug> app: required_size: 0xF860.
<debug> app: single_bank: false.
<debug> app: keep_app: false.
<debug> app: keep_softdevice: true.
<debug> app: SD_PRESENT: true.
<debug> app: Bank contents:
<debug> app: Bank 0 code: 0x00: Size: 0x0
<debug> app: Bank 1 code: 0x00: Size: 0x0
<debug> nrf_dfu_validation: Write address set to 0x00027000
<debug> nrf_dfu_settings: Writing settings...
<debug> nrf_dfu_settings: Erasing old settings at: 0x000FF000
<debug> nrf_dfu_flash: nrf_fstorage_erase(addr=0x0x000FF000, len=1 pages), queue usage: 0
<debug> nrf_dfu_flash: nrf_fstorage_write(addr=0x000FF000, src=0x200084EC, len=896 bytes), queue usage: 1
<info> nrf_dfu_settings: Backing up settings page to address 0xFE000.
<debug> nrf_dfu_settings: Writing settings...
<debug> nrf_dfu_settings: Erasing old settings at: 0x000FE000
<debug> nrf_dfu_flash: nrf_fstorage_erase(addr=0x0x000FE000, len=1 pages), queue usage: 2
<debug> nrf_dfu_flash: nrf_fstorage_write(addr=0x000FE000, src=0x2000816C, len=896 bytes), queue usage: 3
<debug> nrf_dfu_req_handler: Writing valid init command to flash.
<debug> nrf_dfu_req_handler: Request handling complete. Result: 0x1
<debug> nrf_dfu_req_handler: Handle NRF_DFU_OP_OBJECT_SELECT (data)
<debug> nrf_dfu_req_handler: crc = 0x0, offset = 0x0, max_size = 0x1000
<debug> nrf_dfu_req_handler: Request handling complete. Result: 0x1
<debug> app: timer_stop (0x20005998)
<debug> app: timer_fire (0x20005998)
<info> app: Inactivity timeout.
<debug> app: Resetting bootloader.
<info> nrf_dfu_settings: Backing up settings page to address 0xFE000.
<error> app: Received a fault! id: 0x00004002, pc: 0x00000000, info: 0x2003FF20

[Susheel Nuguru]

Not sure what is the reason in your case for the inactivity in the DFU operation but the bootloader implements an inactivity timeout that applies in various cases. This is controlled by adjusting the NRF_BL_DFU_INACTIVITY_TIMEOUT_MS parameter in the bootloader's sdk_config.h. The default value in Nordic's examples is 120000 ms, which is equivalent to 2 minutes. This means that if there is no activity for the specified duration, the bootloader will reset.

In the DFU (Device Firmware Update) mode, the bootloader activates the DFU transports and the device is ready to receive new firmware. When the DFU mode is entered, the inactivity timer is started. On timer expiration, the bootloader resets. The inactivity timer is restarted on any DFU activity.

You can restart the inactivity timer by calling the function nrf_bootloader_dfu_inactivity_timer_restart. This function takes two parameters: timeout_ticks which is the number of ticks until reset, and callback which is the function to be called on timeout.

If you want to change the inactivity timeout, you can adjust the NRF_BL_DFU_INACTIVITY_TIMEOUT_MS parameter in the sdk_config.h file.

[RAJVARDHAN]

Hi Susheel,

We're mainly facing issues with UART data transmission. It transmits the first packet of data, then hangs indefinitely. After waiting for some time, it restarts the bootloader, which is correct after 2 minutes. However, during UART data transmission, even the FOTA process hangs.

Note: while performing DFU the new firmware is going to write in the flash instead of writing the data in flash the same should be sent in the UART. So whenever it is required we will write in flash or we will send same data in UART only one at a time.

>> It hangs after 6%, not completing the FOTA, and the UART data transmission also stops.

[Susheel Nuguru]

What are the settings for the UART when you use it in the DFU? Does it have hardware flow control? what is the baudrate? Have you tried with enabling both hardware flow control and decreasing the baud rate and also increasing NRF_BL_DFU_INACTIVITY_TIMEOUT_MS to some bigger number?

It could be an issue in the UART handling, maybe the UART workflow hangs or deadlocks with the UART settings you have in your application. 

[RAJVARDHAN]

Settings for UART in DFU:

Hardware Flow Control: We have tried both enabling and disabling hardware flow control. The UART only works properly when hardware flow control (HFC) is disabled.

Baud Rate: We initially used a baud rate of 115200 but have since changed it to 9600.

Inactivity Timeout: The default value for NRF_BL_DFU_INACTIVITY_TIMEOUT_MS is 120,000 milliseconds (120 seconds).

We are calling nrf_drv_uart_tx(&m_uart, data, length); in nrf_dfu_ble.c. The function then transitions to nrfx_uarte_tx, where the following code is executed:

nrfx_err_t nrfx_uarte_tx(nrfx_uarte_t const * p_instance,
uint8_t const * p_data,
size_t length)

{

nrf_uarte_task_trigger(NRF_UARTE0, NRF_UARTE_TASK_STARTTX);

//it will hang here .

}

The execution hangs at this point.