CCS/LAUNCHXL-F28027F: standard 8N1 UART signal

Hi,

If you want to interface a UART signal with SCi, you need a RS-232 transceiver like MAX3221.

Regards,
Gautam

Sir , I am interfacing with a device which sends standard uart 8-N-1 signal and i have configured c2000 lauchpad to idle line mode . But Rx pin doesn't get wake-up .
from your reply is there any need of max3221 transceiver .
Also when i have read about idle line mode, i found that ,in this mode we need to define a start of block or end of block frame . but in this case the device is sending random signal , so how to define such start of frame.

Gannamraju,

The Max3221 is not required when using a Launchpad, we already have setup a transceiver to work with GPIO28 and GPIO29 for you.

Are you preforming communication to multiple slaves? If you are preforming a simple point-to-point communication you shouldn't need to put the SCI receiver to sleep. You can simply turn the SCI receiver on in Idle line mode(the default mode) and it should work right away.

As for defining a start-of-block or end-of-block frame: UART is very simple, it is up to the user to define how data is sent. One popular method is to define a Start-of-block frame or frames, you should choose something that will not occur in your data(i.e. A5), or if this is not possible, something that will rarely occur. If your Start-of-block frame might occur in your data you could use a series of several frames(i.e. A5A5A5A5A5) to define the start of data. If you have variable amounts of data one thing that will help the robustness of your code would be to transmit a word containing how many words will be in the block immediately after the start-of-block frame. Alternatively you could use a end-of-block frame.

There are many ways to accomplish this, so take some time and you should find a robust solution that works for you! Do note that adding these frames adds overhead and will reduce your overall throughput.

Hope it helps-Regards,
Cody