这是关于制作下载线的一点小体会，希望上传之后能对大家有所帮助，其中用到的芯片是74HC244，比74LS244好用-This is a download on the production line a little experience, I hope after the upload can be helpful to everyone, which is used in chip 74HC244, easy to use than 74LS244

用74HC244扩展ADUC841的IO口。此处扩展的是P1口，因为P1口不能用位寻址，应该用xdata寻址。比较有代表性。-ADUC841 the IO expansion with 74HC244 mouth. Expansion of the P1 port here, because I can not P1-bit addressing, should xdata address. More representative.

最全的AVR下载线资料，包括74HC244版本，74HC373版本，AVR-USB-ISP，USBasp版本，并口版本，串口版本，串口jtag-AVR download the most complete line of information, including version 74HC244, 74HC373 version, AVR-USB-ISP, USBasp versions, parallel versions, serial version, serial jtag