Bit Banging

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Posted by IM Confused, on Dec-2008,
1. Bit banging
I am confused. A Tx line idles at -15v. When a byte is to be sent, the Tx line goes high (+15v) for the start bit, followed by the data (1=-15v, 0=+15v) sent least significant bit first, followed by the stop bit (-15v). Note that the stop bit doesn't exist, it is just a gap to allow things to syncronize.
 
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Posted by Administrator, on Dec-2008,
1. hi
A communication frame consists of information (i.e.data) and overhead (e.g. start bit, error checking and stop bits) a stop bit is a part of the frame, its a part of synchronization and its better to include it in the code rather that just making the line high and leaving it as it may cause error in communication like sending the next byte without waiting for the stop bit duration
 
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Posted by Conrad, on Jul-2009,
2. Remember RS232 is inverse...
the RS232 levels are not only not the same as those of your micro/cpu logic, but they are inverted. If you use a MAX232 chip or similar, it will do all the work for you. 
 
The inverting is perhaps confusing, but since the micro side is "correct" it is easy to program.
 
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