Homemade simple JTAG download and Writing Tool
For General Embedded Systems enthusiasts, it is unlikely that they will spend too much money to buy a relatively high-end debugging simulation tool to debug our own target board, the most economical method is to create a simple JTAG cable for flash writing. First, the bootloader is solidified into flash, because the bootloader compilation is very small, usually dozens of kb, A maximum of several hundred kb. It does not take much time to use a simple JTAG for writing. If it succeeds, bootloader can work normally, then, you can download other programs to the dram of the Target Board through the serial port or TFTP in the bootloader menu for running debugging or burning the final software, because the download speed through the serial port or TFTP is faster than the download speed of the simple JTAG cable. Of course, you can also search and purchase a simple JTAG cable (very cheap, up to 50 RMB) from the Internet, regardless of the version, then we use the simple JTAG burning software introduced below to burn the flash of the target board, before using the software, you only need to modify the pin variable definition in the source code based on the relationship between the parallel port and the JTAG port in the specific connection diagram of the purchased JTAG cable, and then re-compile the link.
In this chapter, we will introduce the hardware principle of the simple JTAG cable, the software burning process, and the method of using the simple JTAG cable to burn flash.