BLE通知无法发送数据

你好，特里，
将MTU大小增加到39，然后再试一次。确保MTU大小被交换。
请参阅蓝牙4规范第3卷F 3.4.7.1部分。（通知的属性值大小应该在0到MTU - 3之间）。
当做，



     以下为原文
  Hello Terry,
 
Increase the MTU size to 39 and try again. Make sure that the MTU size is exchanged.
 
Please see Bluetooth 4.0 specification Vol 3 Part F 3.4.7.1. (Attribute Value size for notifications should be between 0 and MTU - 3)
 
Regards,

嗨，CFMM，
只想确认在“间隙设置”中改变MTU是否可以？
我需要改变“L2CAP MTU”吗？
谢谢，
特里



     以下为原文
  Hi cfmm,
 
Just want to confirm that is it ok for just to change the MTU in 'GAP settings'?
Do I need to change the 'L2CAP MTU' also?
 
Thanks,
Terry

你好，特里，
在间隙设置选项卡中。



     以下为原文
  Hello Terry,
 
Yes in the GAP Settings tab.

卡洛斯费尔南多梅尔马丁内兹是正确的。根据BLE规范，通知的最大大小是MTU - 3。默认MTU大小是23，这意味着最大通知有效载荷可以是20字节。这就是为什么12字节为你工作，而不是为36工作。当数据长度大于MTU - 3时，GATSnNoTIFICTION（）API将返回一个错误。您可以在代码中检查这一点。
如果要发送大小为36字节的通知，则将MTU大小更改为36 + 3＝39字节。你不必改变L2CAP MTU的大小。只更改关贸总协定MTU大小。



     以下为原文
  [size=0.9em]Carlos Fernando Meier Martinez is correct. According to the BLE spec, the max size for a notification is MTU - 3. The default MTU size is 23 which means that the max notification payload can be 20 bytes. This is why 12 bytes work for you and not 36.

[size=0.9em]The GattsNotification() API will be returning an error when the length of the data is greater than MTU - 3. You can check this in your code.

[size=0.9em] 
[size=0.9em]If you want to send a notification of size 36 bytes, then change the MTU size to 36 + 3 = 39 bytes. You don't have to change the L2CAP MTU size. Change only the GATT MTU size.