PIC模拟异步串行通讯UART。用TMR0实现定时查询。任何带中断的PIC上都可以实现。可用此法扩展多个串口。-PIC simulation asynchronous serial communications UART. Timing TMR0 with inquiries. Any interruption with the PIC are to be attained. This method can be extended serial number.

ZG2100M的datasheet，ZG2100M是zerog的wifi模块，和PIC系列MCU能很好兼容wifi stack-ZG2100M s datasheet, ZG2100M is zerog wifi module, and it provides wifi stack can compatible with PIC series MCU

a good book for usb interface of pic with pc.it explains how you can usb interface the devices with pc.