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I am trying to read GPIO via python. The normal IO via Cypress controller is pretty slow -- about 3 ms poll time in Python.
I want to read the SoC versions of IO2 and IO3. This is the pinMode INPUT_FAST in Arduino. I am assuming this is using SoC IO.
I cannot read input on IO2 or IO3 when I put it in SoC mode, though I can via Cypress mode. Any Pointers?
Here's what I tried:
Steps to enable SoC mode for IO2:
1. Setup MUX control hardware so I/O goes to SoC
2. Setup GPIO14 for IO2
So from what I understand so far, I set the mode of the IO:
Init GPIO 31 as output and set low to select IO2 to use SoC
echo "31" >/sys/class/gpio/export
echo "out" >/sys/class/gpio/gpio31/direction
echo "0" > /sys/class/gpio/gpio31/value
cat /sys/class/gpio/gpio31/value <--- 0, good.
Now set up GPIO 14 as input:
echo "14" >/sys/class/gpio/export
echo "in" >/sys/class/gpio/gpio14/direction
This does not read changes on IO2. However I can toggle the pull up resistor and it DOES detect this change:
echo "0" >/sys/class/gpio/export
echo "out" >/sys/class/gpio/gpio0/direction
echo "0" >/sys/class/gpio/gpio0/value <--- disables the pull up resistor
cat /sys/class/gpio/gpio14/value <----- shows 0
echo "0" >/sys/class/gpio/gpio0/value <--- enables the pull up resistor
cat /sys/class/gpio/gpio14/value <----- shows 1
So the input is getting from the pull up resistor to processor. But not from IO2 to the processor.
however changing to Cypress
echo "1" > /sys/class/gpio/gpio31/value
now enabling the Cypress Input
echo "32" >/sys/class/gpio/export
echo "in" >/sys/class/gpio/gpio32/direction
This responds correctly to changes in input value.
Am I missing something here?
I based my settings on information from Intel Galileo - Programming GPIO From Linux - Malinov Family Web Presence