4位数码管计数器经典例程，可从0000~9999循环计数-4-bit digital tube counter the classic routines from the 0000 ~ 9999 cycle counting

按键0--9999计数器的程序及应用说明，带有汇编程序及说明。-Key 0--9999 counter procedures and application notes, with a compilation of procedures and instructions.