How to sent a 200 bytes data packet via NUS every 20ms between nRF52832 and nRF52840

RE: How to sent a 200 bytes data packet via NUS every 20ms between nRF52832 and nRF52840

Kenneth — Mon, 16 Aug 2021 11:37:45 GMT

If you build with DEBUG then you should get more information about the error from app_error_fault_handler() in app_error_weak.c

Kenneth

RE: How to sent a 200 bytes data packet via NUS every 20ms between nRF52832 and nRF52840

laumung — Fri, 06 Aug 2021 23:40:16 GMT

Since the "Windows size" and "interval" is a index number and the real time is about "1.25" proportional to the number, so I guess we should correct the MIN_CONN_INTERVAL and MAX_CONN_INTERVAL in the peripheral. Am I right? But when I decreased the parameters to 5 and 35 respectively, The peripheral will keep in fatal errors. How to correct that? Thanks.

RE: How to sent a 200 bytes data packet via NUS every 20ms between nRF52832 and nRF52840

laumung — Fri, 06 Aug 2021 00:11:50 GMT

On the central side, I used "nrf52-ble-app-uart-c-multilink-master" as example. It's also based on the "ble_app_multilink_central" project in "ble_central " folder. I didn't find any connection parameter in main.c but I get some in the sdk_config.h files which listed below. Does it match the peripheral firmware? Thanks.

// <o> NRF_BLE_SCAN_SCAN_INTERVAL - Scanning interval. Determines the scan interval in units of 0.625 millisecond. 
#ifndef NRF_BLE_SCAN_SCAN_INTERVAL
#define NRF_BLE_SCAN_SCAN_INTERVAL 160               //160
#endif

// <o> NRF_BLE_SCAN_SCAN_DURATION - Duration of a scanning session in units of 10 ms. Range: 0x0001 - 0xFFFF (10 ms to 10.9225 ms). If set to 0x0000, the scanning continues until it is explicitly disabled. 
#ifndef NRF_BLE_SCAN_SCAN_DURATION
#define NRF_BLE_SCAN_SCAN_DURATION 0
#endif

// <o> NRF_BLE_SCAN_SCAN_WINDOW - Scanning window. Determines the scanning window in units of 0.625 millisecond. 
#ifndef NRF_BLE_SCAN_SCAN_WINDOW
#define NRF_BLE_SCAN_SCAN_WINDOW 80                     //80
#endif

// <o> NRF_BLE_SCAN_MIN_CONNECTION_INTERVAL - Determines minimum connection interval in milliseconds. 
#ifndef NRF_BLE_SCAN_MIN_CONNECTION_INTERVAL
#define NRF_BLE_SCAN_MIN_CONNECTION_INTERVAL 7.5       //7.5
#endif

// <o> NRF_BLE_SCAN_MAX_CONNECTION_INTERVAL - Determines maximum connection interval in milliseconds. 
#ifndef NRF_BLE_SCAN_MAX_CONNECTION_INTERVAL
#define NRF_BLE_SCAN_MAX_CONNECTION_INTERVAL 30      //30
#endif

RE: How to sent a 200 bytes data packet via NUS every 20ms between nRF52832 and nRF52840

laumung — Thu, 05 Aug 2021 17:55:47 GMT

Hi Kenneth, thank you for your reply. I have tried other examples in the nRF5 SDK and it's lots of migration between the firmware. I will try later. This firmware also based on the example which NORDIC released and it's also released by NORDIC I think.

I have checked my code, as you said. The configuration of the peripheral is listed below and I didn't find the definition of connection intervals to be 30ms.

I have modified data-mode="text">#define APP_BLE_CONN_CFG_TAG 1 /**< A tag identifying the SoftDevice BLE configuration. */ "Nordic_UART_SAADC_01" /**< Name of device. Will be included in the advertising data. */ BLE_UUID_TYPE_VENDOR_BEGIN /**< UUID type for the Nordic UART Service (vendor specific). */ 3 /**< Application's BLE observer priority. You shouldn't need to modify this value. */ 64 /**< The advertising interval (in units of 0.625 ms. This value corresponds to 40 ms). */ 18000 /**< The advertising duration (180 seconds) in units of 10 milliseconds. */ MSEC_TO_UNITS(10, UNIT_1_25_MS) // 20 /**< Minimum acceptable connection interval (20 ms), Connection interval uses 1.25 ms units. */ MSEC_TO_UNITS(75, UNIT_1_25_MS) /**< Maximum acceptable connection interval (75 ms), Connection interval uses 1.25 ms units. */ 0 /**< Slave latency. */ MSEC_TO_UNITS(4000, UNIT_10_MS) /**< Connection supervisory timeout (4 seconds), Supervision Timeout uses 10 ms units. */ APP_TIMER_TICKS(5000) /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */ APP_TIMER_TICKS(30000) /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */ 3 /**< Number of attempts before giving up the connection parameter negotiation. */ 0xDEADBEEF /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */ 256 /**< UART TX buffer size. */ 256 /**< UART RX buffer size. */ 4 4 /**< SAADC sample rate in ms. */ 20 // MING NRF_SDH_BLE_TOTAL_LINK_COUNT); /**< BLE NUS service instance. */ /**< GATT module instance. */ /**< Context for the Queued Write module.*/ /**< Advertising module instance. */ the parameter "MIN_CONN_INTERVAL" to 10ms and nothing else. Which code is related to the connection interval? Thanks.

RE: How to sent a 200 bytes data packet via NUS every 20ms between nRF52832 and nRF52840

Kenneth — Thu, 05 Aug 2021 06:49:46 GMT

I suggest to check out the throughput example project in the nRF5 SDK. For instance your connection interval is rather slow (30ms), it should be possible to lower this to for instance 7.5ms if you have an nRF device in both ends of the link:

Another strange thing is that I can see the master is skippin many connection intervals, it should be consistenly 30ms, but instead I can find it's both ~30, ~60, and ~90ms intervals. Likely this indicate that the central is busy scheduling other BLE activities, either other links, scanning etc. So this will have e negative effect on the throughput for the link you are monitoring.

Not quite sure what you can tell me about the other BLE activities the central is doing here, but that seems to be the main limiting factor.

Kenneth

RE: How to sent a 200 bytes data packet via NUS every 20ms between nRF52832 and nRF52840

laumung — Thu, 05 Aug 2021 02:16:23 GMT

Here is the data snap by nordic Sniffer.

devzone.nordicsemi.com/.../0804.pcapng

RE: How to sent a 200 bytes data packet via NUS every 20ms between nRF52832 and nRF52840

laumung — Wed, 04 Aug 2021 23:23:08 GMT

Hi Kenneth, thank you for your reply. I have install the Nordic sniffer le on another NRF52 DK board and capture the data on BLE. This is what I capture in the BLE network. How can I analysis the data?

RE: How to sent a 200 bytes data packet via NUS every 20ms between nRF52832 and nRF52840

Kenneth — Tue, 03 Aug 2021 07:25:59 GMT

Hi,

I suggest to check out this page that describe some good tips:
https://www.novelbits.io/bluetooth-5-speed-maximum-throughput/

To find what may be reducing the throughput further we may need an on-air sniffer log:
https://infocenter.nordicsemi.com/topic/ug_sniffer_ble/UG/sniffer_ble/intro.html

Best regards,
Kenneth