Author Topic: Inverted RTS signal on serial smartboard  (Read 727 times)

nick

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Inverted RTS signal on serial smartboard
« on: November 18, 2009, 02:04:03 PM »
One of the nice things about the serial smartboard is that the signal levels can be set to plug right into a microprocessor UART --  normally to connect the output of a UART to a RS232 circuit you would need a signal inverter.  However, on the family of microprocessors I use most -- Atmel -- the RTS/CTS signal used for flow control is also inverted.  So the RTS signal coming off of the ioBridge is the exact opposite of what CTS on the UART is expecting, and needs to be run through an inverter to implement flow control, even though the RX and TX lines don't need to be.  Having the behavior of the RTS line configurable, as the RX and TX lines are, would save a component and simplify circuit design.

jason

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Re: Inverted RTS signal on serial smartboard
« Reply #1 on: November 19, 2009, 05:14:25 PM »
That's a good point.  In doing all the analysis to figure out which polarity would server the most users, I missed the obvious: let the use decide!

Although the serial board you have right now can't be changed, I can add that option to the next batch of serial boards.

Thanks for the suggestion. 
Jason Winters
ioBridge Developer