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jecottrell
Joined: 16 Jan 2005 Posts: 559 Location: Tucson, AZ
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OT Hardware Question, Isolating a Shared UART Line |
Posted: Tue Nov 13, 2012 5:30 pm |
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I've got a weird situation where I need to use a hardware UART and it is connected to an FTDI USB and a Bluetooth radio. In one situation I need to disable the TX line from the PIC to the Bluetooth radio to prevent the radio from communicating accidentally back to the PIC. I think I've got a signal from the FTDI chip that I can use to "control" the disabling of the TX line but I'm not sure how to do it "gracefully".
Is there a piece of hardware that is meant to achieve this task or maybe some way with discrete components? Even just some terms that would help with a Google search for what I'm trying to do would help.
Thanks,
John |
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ezflyr
Joined: 25 Oct 2010 Posts: 1019 Location: Tewksbury, MA
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Posted: Tue Nov 13, 2012 6:57 pm |
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Hi John,
I think an 'Analog Switch' would do quite nicely. A number of manufacturers (Maxim, ON Semi) even list 'UART/USB/Data Multiplexing' as a typical application.
John M. |
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jecottrell
Joined: 16 Jan 2005 Posts: 559 Location: Tucson, AZ
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Posted: Tue Nov 13, 2012 8:10 pm |
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Perfect!
SN74 Single FET Bus Switch....
Thanks for the help. |
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asmboy
Joined: 20 Nov 2007 Posts: 2128 Location: albany ny
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Posted: Wed Nov 14, 2012 10:17 am |
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A pair of 74HC08 and gates - with an inverter driving on alternate gate B select will do nicely as these are only 0-5V or 0-3.3v levels. |
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