CC2640 peripheral not able to connect after multiple connects-disconnects

Danny Chan

Other Parts Discussed in Thread: BLE-STACK

I'm running into an issue where my BLE Peripheral with TI BLE-Stack 2.2.0 is no longer able to connect to a Central.

I have a custom board with the CC2650DK_4XS using the internal low-frequency RC oscillator (RCOSC_LF without the 32kHz crystal), and I've loaded it with simple_peripheral with a few minor tweaks (no display and different connection parameters). I ran a basic test where the Central connects, discovers services, read characteristics and disconnects. Initially it worked fine, but after running the test multiple times, the Peripheral can no longer stay connected to the Central. I could see ADV_IND from the Peripheral, as well as CONNECT_IND, but ~200ms afterwards the Peripheral starts sending ADV_IND again with no apparent disconnect reasons.

The following are the steps to reproduce the issue:

1. Install TI BLE-Stack 2.2.0 ble_sdk_2_02_00_31_setup.exe
2. Open IAR workspace C:\ti\simplelink\ble_sdk_2_02_00_31\examples\cc2650em\simple_peripheral\iar\simple_peripheral.eww
3. Select the FlashROM_RCOSC build configuration
4. Set the defined symbols for cc2650em_app – FlashROM_RCOSC:

USE_ICALL
USE_RCOSC
POWER_SAVING
HEAPMGR_SIZE=0
Display_DISABLE_ALL
BOARD_DISPLAY_EXCLUDE_UART
BOARD_DISPLAY_EXCLUDE_LCD
ICALL_MAX_NUM_TASKS=3
ICALL_MAX_NUM_ENTITIES=6
xdc_runtime_Assert_DISABLE_ALL
xdc_runtime_Log_DISABLE_ALL
CC2650DK_4XS
CC26XX

5. Exclude Startup/ccfg_app_ble.c from build configuration
6. Include Startup/ccfg_app_ble_rcosc.c to build configuration
7. Change connection parameters in simple_peripheral.c:

#define DEFAULT_DESIRED_MIN_CONN_INTERVAL 300
#define DEFAULT_DESIRED_MAX_CONN_INTERVAL 315
#define DEFAULT_DESIRED_SLAVE_LATENCY 4
#define DEFAULT_DESIRED_CONN_TIMEOUT 600
#define DEFAULT_CONN_PAUSE_PERIPHERAL 0

8. Rebuild and download cc2650em_app
9. Rebuild and download cc2650em_stack

I used a Samsung S6, Android version 5.0, with BluePixel's BLE Scanner App version 3.6. Note that BTool/HostTest was also unable to maintain a connection after the issue happened.

Sniffer trace are attached.

no connection.zip

over 8 years ago

0 A. Rebel over 8 years ago

TI__Genius 11740 points

Hi Danny,

Thanks for the detailed instructions, we'll attempt to reproduce on our side.

Regards,
-Rebel

0 A. Rebel over 8 years ago in reply to A. Rebel

TI__Genius 11740 points

Hi Danny,

I followed the instructions - only modifications I made were to use the Launchpad instead of the 4XS. Everything seems to be working fine. (Performed multiple connections/GATT reads/disconnections similar to what your sniffer captures show.)

Can you give me more information about the modifications you made to the application? It appears you're using the GAPBondMgr in the sniffer captures, what other modifications did you use?

Can you reproduce this on a launchpad?

Regards,
-Rebel

0 JXS over 8 years ago in reply to A. Rebel

TI__Guru** 105180 points

Hi Danny,

Do you see different/improved results if you disable POWER_SAVINGS?

Also, just to be clear, are you using a 4x4 QFN with a single-ended, external bias RF layout? Do you access to the CC2650EM_4XS eval module where you can run the same test?

Best wishes

0 Danny Chan over 8 years ago in reply to JXS

Intellectual 440 points

Hi A. Rebel,

The simple peripheral comes default with gap bond manager, and reading characteristic 0xFFF5 requires authentication.

Hi JXS,

There's no way our low-power device can support POWER_SAVINGS, but I did try the same test on one of our custom 7ID PG2.3 LF_RCOSC device (and defining CC2650DK_7ID in the simple peripheral RCOSC project), and unfortunately I observed the same issue. I've attached the executable for both 4XS and 7ID, as well as sniffer traces (in multiple replies; files too big). I'll following up with our TI FAE and I'll send him this link as well.

PS. I tried the same test on TI BLE-Stack 2.2.1, and so far I haven't seen the issue.

Thanks. Danny

4XS.zip