The current programming methods are generally divided into offline programming and online programming.
Offline programming: through the adapter to connect different packaged chips, and only the chip and the adapter are used together can achieve the programming of PCBA. The nature of the adapter is similar to a precision fixture, and different packaged chips need to be matched with different adaptors. If there are any errors in the PCBA production testing, it is necessary to conduct the production backtracking and revise, and the chip needs to be removed from the PCBA and then re-program in accordance with the prescribed process, which will consume a lot of manpower and material resources, so the cost is high. It is also prone to cause problems, so offline programming is generally not recommended.
Online programming: The online programming of PCBA processing uses standard communication bus of chip, such as USB, SWD, JTAG, UART, etc. The interface is generally fixed, and there are few pins that need to be connected during programming. Because the interface communication rate is not high, the programming can be completed by using ordinary wires without high cost consumption. Online programming conducts programming through wire connection. If any errors are found during PCBA production testing, you can reprogram without disassembling the chip. It not only saves production costs, but also improves the efficiency of programming. Therefore, online burning is generally used now.