PCBA technology has become increasingly mature, played a key role in the current various intelligent equipment，It has a wide range of applications. If you want the printed circuit board to achieve the desired design function, except the hardware, the matching support of the software is very important, the program is loaded into the IC through the way of programming, then how to achieve the IC programming in PCBA processing? Next, UETPCB will introduce it to you.
What is the PCBA IC programming?
PCBA IC programming is the process of transferring the program into the internal storage space of the chip, using a debug/programming socket/probe before being mounted on the PCB, normally divided into offline programming and online programming.
Most PCBA factories provide programming interfaces for Arm, AVR, MSP430 MCUs. And basic structure of any programmable IC has a section for memory, there are all kinds of memories, such as EEPROM. PROM. ROM, RAM, SRAM etc.
Off-line programming
Through a variety of adapters compatible with different packages of chips, chips and adapters can be used together to achieve programming for ICs. Adapter itself is a kind of precision fixture, different chips, different packages need to choose different fixtures.Now the EMMC which is widely used and other chips, they tend to BGA, QFN and other small packages, and the price of this kind of packaging adapters is high.
But if there is an error happened when doing the PCBA test, then the production backtracking should be revised, also the chip should be removed from the adapter and re-do the programming follow with the prescribed process, and there may exist some other problems during PCBA processing, such as the PCB circuit board material with a low TG and cannot support the high temperature when removing the chip, then the chip will be broken, which is time-consuming and high cost, meanwhile, it will increase the risk of scrapping.
On-line programming
Online programming is the standard communication bus of the chip, such as USB, SWD, JTAG, UART, etc., the interface is generally fixed, and the fewer connect pins are needed when programming. As the interface communication rate is not high, and using the common wires can complete programming.
If there is an error when doing the production test, the production backtracking can be immediately revised, and re-start the programming, no need to remove the chip. Because the online programming is through the wire connection, Not only save production cost, but also increase the efficiency of programming. Now most PCBA factories will choose online programming to program an IC.
Common IC programming methods and what is the interface and tool?
1, JTAG
JTAG used JLINK, can meet the need of most chips programming.
The standard JTAG interface is generally 20/14/10pin, its hardware interface mainly includes: RST, TDI, TMS, TCK, TDO, REST, VCC, GND and so on.
2, SWD
This method mainly uses SWDIO and SWCLK wire. JLINK also supports debugging with SWD.
3. ISP
ISP downloads using UART interface, TXD and RXD should be cross-connected. Using USB/TTL, which is very cheap.
How to ensure correct IC programming?
1, Ensure that the wires connected correctly.
2. Ensure the power supply voltage correctly.
3. Ensure that the parameters of the crystal oscillator circuit are correct and the connection is normal.
4, If there is an external reset circuit, to ensure that it works normally.
5, The most critical, the first operation of the programming software into the programming state, and ensure that the setting is correct, and then power-on (attention is to power off after a certain time).