I use two development boards AduC812 from Phytec. Both boards collect the data of two temperature sensors via analog/digital converter. This works without any problems. Because of missing hardware components (only one COM port) the analog/digital converted signals of these two boards must be transmitted via one rs232 cable to the personal computer. My question is how to built a daisy-chained rs232 cable. And how implement this in a µvision2 c# code?
"Because of missing hardware components (only one COM port) the analog/digital converted signals of these two boards must be transmitted via one rs232 cable to the personal computer."
Are you saying that the deficiency is in the PC because it has only one COM: port?
If so, can't you just add a USB-to-RS232 adaptor to gain a second COM: port? surely, this would be far simpler than any messing about trying to multiplex devices onto one COM: port?!
Possibly better still, get a double USB-to-UART adaptor - then you only need one connection to the PC! eg, apple.clickandbuild.com/.../ftdichip
Walter Wenz ask the very same question (and get the same answers) here www.8052.com/.../168316
go figure
Erik