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9 years, 9 months ago.
UART TX Open Drain configuration
How can one get UART out forced to open drain rather than using the internal pull up ?
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1 Answer
9 years, 9 months ago.
In principle such things aren't supported by the standard libs, but what you can try, assuming your device supports open-drain mode in the first place from hardware, is use the function:
pin_mode(PinName pin, PinMode mode) ;
Pin is obviously the pinname, mode is OpenDrain.
You might need to include pinmap.h
Tried this but no effect. With open drain adapted hardware or not (LPC1768 MBED board alone), I still see 0-3,3V transition on the output...
From what I read somewhere else, there seem to have a silicium bug in the LPC1769 which prevent the UART to effectively provide open drain output. Maybe it is the same on LPC1768.
posted by 12 Aug 2014