MSP430FR2355: pullup/down question?

Steve Wenner

When a pin is reconfigured from a GPIO with pullup/pulldown to another mode of operation as an input (such as SPI --- MISO) can it retain the pullup / pulldown ? or do these only work in GPIO mode?

Thanks

over 3 years ago

0 Keith Barkley over 3 years ago

Guru 42725 points

It looks to me that it only works in GPIO Input mode:

0 Steve Wenner over 3 years ago in reply to Keith Barkley

Genius 3240 points

I looked at that and wasn't able to come to that conclusion....ie PxSEL0/1 for MISO would allow one of these to be low which would enable the input hysteretic buffer. Certainly POUT can still be used to control pullup/pulldown and PREN could be enabled but beyond that it looks like it would work???? Not sure what the block labeled "bus keeper" is doing....

+1 Bruce McKenney over 3 years ago

Guru 102065 points

Observed behavior is that they do operate in I2C mode.. I haven't tried it with SPI/UART.

A scope/voltmeter and some poking with the debugger might be informative. (Let us know what you find.)

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MSP430FR2355: pullup/down question?