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Gpio questions on useage


spottyrover

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I am looking for some recommendations for using the Gpio on the opi PC ( with uname -r 5.7.15-sunxi )


The project is to open and close a glass house door using a temperature probe ( ds18B20 ) and a relay control board ( opto coupled with active low input ).
Later I will add automatic watering relay board.

 

The pins I would like to use are

Inputs

PC0     used for ds18B20   (SPI0_MOSI)    because it is an Input

PC4    Door closed switch         Internal pullup            
PC7    Door is fully open switch     Internal pullup
PC3     Input to be used later(SPI0_CS) Innternal pullup

 

Outputs
PD14            output  MC  motor close door
PC1     (SPI0_MISO)    output  MC  motor close door    because it is an output


Proposed outputs to be used later

PA0    (UART2_TX/JTAG_MS/PA_EINT0)    
PA11    (TWI0_SCK/DI_TX/PA_EINT11)
PA13 (SPI1_CS/UART3_TX/PA_EINT13)
    
PG6    (UART1_TX/PG_EINT6)

 

Data  from Allwinner H3 Datasheet

 

I am using these commands to set inputs
echo 71 > /sys/class/gpio/export
echo "in" > /sys/class/gpio/gpio71/direction

 

My questions are:
1) what do you think of the chosen pins?
2) Do I need to do anything to configure inputs to use pullups?
3) How can I set output pins to start out as high so as not to trigger the relay on startup?
    I am trying to use  for outup
                  echo 110 > /sys/class/gpio/export                #    pin12    PD14    MCD o/p relay    110
                  echo "out" > /sys/class/gpio/gpio110/direction
                  echo 1 > /sys/class/gpio/gpio110/value    
which causes the relay to turn ON then OFF

 

Thanks for all of your advice
Dave
 

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