Dear Dialog,
我开发了一个带有Murata LBCA2HNZYZ BLE模块的产品（包括DA14580芯片）。
该产品有两个模块，一个是中央，另一个是外围设备。
But after connected to each other, peripheral never responds a few times an hour.
The distance between central and peripheral is around 6 meter. And there is not radio wave interference at my environment.
At my test code, central sends a one packet which has 23 octet PDU-length every 50ms.
In many cases peripheral responds an ACK with empty packet.
But peripheral never sends any responce suddenly after sending a packet from central.
此时，Central致以同一数据包（重试）。
And finally they disconnect because central never get any packet from peripheral.
在这种情况下，外设发送错误的BLE堆栈（GAPC）“0x3D（由于麦克风故障而终止）”。
Please help me to find the reason why the disconnect and how to improve the stability of the connection.
以下是我环境的详细信息。
[SDK]
3.0.10.1
[BLE setting]
WinSize :02
WINOFFSET：0x0002
间隔：0x0006
Latency :0x0000
超时：0x0048
ChM :0x1FFFFFFFFF
SCA：0x00.
Encryption is enable.
使用MIDI在蓝牙协议上
Hi Shun Kudoh,
This kind of reason for link termination is a bit rare to happen and also is a bit strange, since the MIC in at the Controller level, i dont think that there are much to do via software in order to cause that disconnection reason, even if it was a bad antenna or a noisy enviroment you should be able to retransmit. The only thing that comes to mind, that perhaps, can cause this kind of disconnection is the use of the AES hardware by your software, perhaps in case you are using this hardware block, it isn't shared properly. Also try to replace the device of the central or the peripheral in case one of those doen't function properly.
谢谢MT_dialog
Dear Dialog,
Thank you for your reply!
Actually I use an AES hardware in DA14580 because our BLE connection is encrypted.
I have conducted some more tests. Here are additional facts.
1.我可以用强复制同样的问题g two Murata EVK (LBCA2HNZYZ-TEMP-DK) and our software.
2.当我们的外设连接到MacBook时，没有问题。
[BLE setting]
WinSize :03
间隔：0x000F.
Latency :0x0000
Timeout :0x0064
ChM :0x1FFFFFFFFF
SCA：0x05
Encryption is enable.
使用MIDI在蓝牙协议上
3. There is no problem when other peripheral (which doesn't use encryption) is connecting to our central.
[BLE setting]
WinSize :02
间隔：0x0006
Latency :0x0000
超时：0x0048
ChM :0x1FFFFFFFFF
SCA：0x00.
加密禁用。
使用MIDI在蓝牙协议上
4. I can reproduce same issue with longer connection interval (7.5->15ms) and timeout (720->1000ms).
5. There is no problem when the central and the peripheral are set closer (0-3m).
我想中央加密方法存在一些问题。
我期待着您的回音。
谢谢！
顺庚
Hi Shun Kudoh,
关于加密，我的介绍是什么，如果在您的中心侧使用命令，请按顺序进行应用程序级别实现使用加密硬件？更具体地说，如果应用程序中的任何位置，则使用以下命令GapM_USE_ENC_BLOCK_CMD？由于您在应用程序中使用安全性，堆栈将处理所有加密操作，您不必从您的应用程序中执行任何操作。
But besides that, the fact that when there is minimum distance between the devices you dont see this happening this would indicate an antenna problem. Also by the sniffer log i ve noticed that you have retransmittions (unexpected SN), can you provide some info regarding the XTAL32 that you use (if you are using, type etc). Also can you please switch the boards between the central and the peripheral for example pcb central -> fw peripheral and pcb peripheral ->fw central and check if you can catch the same error in the central this time.
谢谢MT_dialog
Dear Dialog,
我不使用命令gapm_use_enc_block_cmd。
I only use a Bond and an encrypt command in sample code's macro of BLE_APP_SEC.
我不使用32khz xtal和睡眠模式。
I have tried to exchange the hardware of Murata EVK (LBCA2HNZYZ-TEMP-DK) in order to switch from central to peripheral and peripheral to central.
But I have been able to reproduce this issue.
现在我正在尝试在中央和外围都有同样的测试而没有加密。到目前为止它似乎很好（一小时）。
我将继续进行这次测试。
谢谢！
顺庚
Hi Shun Kudoh,
由于您已更改硬件并且您能够重现问题，是从外设侧的断开连接（外设报告MIC错误作为断开的原因，并且由于中央的故障麦克风字段包而下降，因此如前所述）或中央侧（MIC断开原理出现在中央，由于包裹包上的包上的错误麦克风领域）？
如果没有安全性和加密，您可能会因超时而丢失，因为您不使用加密，因此不应获得MIC原因断开连接。
谢谢MT_dialog
Dear Dialog,
在许多情况下，断开从外围侧。但也脱离了中央侧面。
而且没有安全性和加密，我没有得到任何断开连接，包括超时（代码0x08）。
I have used a DA14580 with 7.5 ms fastest interval and security and encryption with 16 MHz xtal.
I guess there maybe some lack of performance in the core.
(And also I guess that the core needs more power when central and peripheral are put at a distance.)
The DA14580 has hardware AES peripheral, but security and encryption need some core power?
I wonder if I could get an information about a performance margin at both [7.5 ms connection interval + security and encryption] and [7.5 ms connection interval only] situation.
谢谢！
顺庚
Hi Shun Kudoh,
It seems a bit weird for the encryption to impose a delay in the to the system since the encryption its done via hardware, we are checking though and we will let you know. Also just to verify if the connection interval is larger, 50 ms or 100 ms for example you dont get a disconnection with that reason ?
谢谢MT_dialog
Dear Dialog,
I have tested with 100 ms connection interval and using encryption.
And I was able to reproduce same issue (0x3D CONNECTION TERMINATED DUE TO MIC FAILURE from peripheral).
I'm looking forward to hearing from your update.
谢谢！
顺庚
Hi Shun Kudoh,
If that is the case then the interval of the connection seems unrelated to the issue, and the lack of performance in the core can be crossed out. Is it possible to share your code over mail in order to try to replicate the issue ?
谢谢MT_dialog
Dear Dialog,
Thank you for your support.
你能告诉我一个我应该发送代码的地址吗？
我在网站上寻找一个地址，但我找不到...
Thank you,
顺庚
Hi Shun Kudoh,
A mail has been sent to the registered email address.
谢谢MT_dialog
Dear Dialog,
I got your mail! And I sent my code.
谢谢
顺庚