On Thu, Jan 25, 2018 at 10:43 AM, Michael Trimarchi michael@amarulasolutions.com wrote:
SION bit should be used in the situation that we need to read back the value of a pin and should not be set by default macro.
We get some mulfuction as raised by following thread
malfunction
https://www.spinics.net/lists/linux-usb/msg162574.html
As reported by this application note: https://www.nxp.com/docs/en/application-note/AN5078.pdf
The software input on (SION) bit is an option to force an input path to be active regardless of the value driven by the corresponding module. It is used when the nature direction of a pin depending on selected alternative function is an output, but it is needed to read the real logic value on a pin.
The SION bit can be used in: • Loopback: the module of a selected alternative function drives the pad and also receives the pad value as an input • GPIO capture: the module of a selected alternative function drives the pin and the value is captured by the GPIO
SION pin is not necessary when the pin is configured as a peripheral
SION bit
Apart from these minor typos:
Reviewed-by: Fabio Estevam fabio.estevam@nxp.com