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TMS320LF2407A SCI Port troubles.

Started by heath_on_ym December 4, 2008
I am having trouble when using the DSP's SCI port using "idle-line
mode" (versus "address mode"). When attempting to send a string of
characters, the first character sent is always duplicated on the
receiving side unless I set SCICTL1.3 (TXWAKE) then write a "don't
care" character to SCITXBUF. When I perform this action, the first
character is not duplicated.

According to the documentation, when using idle-line mode, when you
set TXWAKE and write the "don't care" byte, the documentation
states "write a 1 to TXWAKE, then write data to register SCITXBUF
to generate an idle period of 11 data bits".

The documentation does not state that when begining a transmision
that creating the idle period is required (otherwise the first
character is duplicated). I cannot find any references in the
documention that states when the idle-period must be re-generated to
avoid the character duplication. For example, if the transmitter is
idle for one character time, do I need to create the "idle period"
of 11 data bits again?

When testing with the TMS320F28335, I do not see this duplication of
the first character.

Does anyone have some insight in to this issue?

Thanks.