ModBus通讯，软件模拟SPI通讯，PIC16F8,ModBus communication, software simulation SPI communications, PIC16F8

sending 4 bytes trhoug USB, an then truoug SPI to a 16f8-sending 4 bytes trhoug USB, an then truoug SPI to a 16f877

；*** *** ***PIC16F87X CAN通信程序**************** list p=16f877 ；定义微控制器为PIC16F877芯片 include "p16f877.inc" ；16F877芯片的寄存器定义 include "MCP2510.inc" ；MACP2510芯片的寄存器定义 ；**************寄存器与变量定义******************* TxBytes equ 0x20 ；SPI发送数据