problem: the project needs to develop 485 serial communication on the android panel. The serial port needs to be monitored after the read command is sent, and the communication is not considered to have failed after N time. Use java s FutureTask with F...
recently, after writing a PLC communication protocol, I sent it a command to read 1 byte after the address 0x0000 (the address 0x0000 exists in PLC, and sent successfully, and the data sent is correct), it should send me 12 bytes (including ACK, site nu...
problem description Open two serial ports at the same time in Android environment, one of them receives the instruction and sends the instruction to the other, but the command of the second serial port will block and often return garbled or the two in...
is using RXTX to write its own communication protocol. At present, one of the problems encountered is: a sends data to B, assuming that the header data of frame I received by B fails to pass, and B requires A to resend, so how can I correctly deal with ...
the following code: let exp = null; try { firefox make this error exp = new RegExp( (?<! $) $( d+| w+? b) , g ); } catch (error) { exp = new RegExp( $( d+| w+? b) , g ); } ** * * * @param {...
The method add (capture-sharp2-of? Super Integer) in the type List < capture-sharp2-of? Super Integer > is not applicable for the arguments (Number) public static void down(List<? super Integer> numberList) { Number x = 4; num...
access a third-party interface (such as ip3:8080 foo) via Nginx redirect location foo { proxy_pass http: ip3:8080 foo ; } Local = = > Nginx on Ali CVM (ip2) = > third-party interface (third-party interface has a whitelist to restrict ip2 in wh...
mongodb implements document locking. When a document is updated, a write lock is created on the updated document, and the document cannot be read or modified at the same time. if mongodb connection pool establishes multiple connections, multiple reque...
1. Due to the needs of the business scenario, the route jump is controlled through js, and there is no programmatic route navigation in the react-router4 documents. https: codeshelper.com q 10. I found this article on the website, but I can only get...