Using Additional BLE GATT Notify Characteristic Does Not Work

[Pamela Keiles]

Hello there,

I have a custom service which includes 5 characteristics, 2 of them use the notify property. I am able to get the first one to work properly, and verified that the configuration update callback occurs to enable the notify. However I am not able to use the second notify characteristic and the configuration update does not occur. I have verified that the "CONFIG_BT_GATT_NOTIFY_MULTIPLE" parameter is set but it still does not work. 

Below are my custom Bluetooth configuration parameters:

# Bluetooth basic configurations
CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_NAME="Soberlink Connect"
CONFIG_BT_DEVICE_NAME_DYNAMIC=y
CONFIG_BT_DEVICE_APPEARANCE=0
CONFIG_BT_MAX_CONN=1
CONFIG_BT_MAX_PAIRED=1
CONFIG_BT_GATT_NOTIFY_MULTIPLE=y
CONFIG_BT_RX_STACK_SIZE=2048
CONFIG_BT_USER_DATA_LEN_UPDATE=y
CONFIG_BT_DATA_LEN_UPDATE=y
CONFIG_BT_AUTO_DATA_LEN_UPDATE=y

# Over-ride various BT settings for extended data packet size
CONFIG_BT_ATT_PREPARE_COUNT=2
CONFIG_BT_CTLR_DATA_LENGTH_MAX=251
CONFIG_BT_CTLR_RX_BUFFERS=2
CONFIG_BT_L2CAP_TX_MTU=247
CONFIG_BT_L2CAP_TX_FRAG_COUNT=10
CONFIG_BT_BUF_EVT_RX_SIZE=251
CONFIG_BT_BUF_CMD_TX_SIZE=251
CONFIG_BT_BUF_ACL_RX_SIZE=251
CONFIG_BT_BUF_ACL_TX_COUNT=10
CONFIG_BT_BUF_ACL_TX_SIZE=251
CONFIG_BT_BUF_CMD_TX_COUNT=10

Let me know if you need more information. Thanks for your help.

Regards,

Pam

[Pamela Keiles]

I have one other detail I found regarding this issue. When I connect to my device using the nRFConnect App on my phone (as the client), I noticed both notify characteristics where individually displayed, however the "Client Characteristic Configuration" descriptor for both of them was the same UUID value. That seems wrong, shouldn't they be different?

[Pamela Keiles]

Never mind, I fixed this issue. We modified the characteristic in our custom app to be of the type "read" versus "notify". 

Thanks anyways, you can close this issue.

Regards,
Pam