说明：  我自己做的s51/52单片机实验板的原理图和PCB（protel99se格式），扳上自带ISP接口，通过并口可以下载程序，可以直接拿去做板，经证明绝对好使，已经售出多块，请大家放心下载
(I do s51/52 micro-controller board the schematic and PCB (protel99se format), wrenches auto ISP interface, can be downloaded through the parallel port procedures can be done directly with boards, proved so absolute, has sold several pieces, please rest assured Download)