hi:

I'm using a 19 channels serial ADC, TLC545. The PC select one of the 19 channels of the ADC. The converted data of the selected channel is received by 51 and sent back to PC using 51's UART.

The PC outputs multiplexer address to 51, and 51 sends data back to PC. But PC shall not know what channel's data is being transferring at the moment because the data of the two channels are sent by turns.

likes this: 1,2,1,2,1,2,1,2...

I want to plot two graphs, which show the voltage of the selected 2 channels. There are protocal between modem and PC, so is there any protocol that is used among 51 and serial devices or I have to design my own protocal for data transfer?

Stanley