Setting outputs on GPIO in code

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Nafai
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Posted by Nafai: Wed. May 19, 2021 - 11:14 PM
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I have a port pin set in START as an input to an ADC, but in code I also need to set that same pin temporarily as an output with push pull set high.  The code I'm using so far is this:

 

gpio_set_pin_direction(AD0, GPIO_DIRECTION_OUT); //set direction to output
gpio_set_pin_level(AD0, true); //set output level hi

//gpio_set_pin_function(const uint32_t pin, uint32_t function)  //the function define I don't know what to set to

 

I'm trying to set the pin to a push pull style output with a good drive capability.  The output does not go hi and I suspect its because I need to add that last line for set_pin_function to set it to push/pull or something.  But I can't find any listing for the names (defines) I can use for the second parameter.  It's for a SAMS70 chip

 

Also, when I want to go back to using the AD, is this the only lines I need (i.e. analog)?

 

gpio_set_pin_direction(AD0, GPIO_DIRECTION_OFF); //pin in low power state

 

This topic has a solution.

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Tools, Atmel Software Framework (ASF) and Atmel Start (ASFv4) (ARM-related), solved
Last Edited: Thu. May 20, 2021 - 06:23 PM
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awit
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Posted by awit: Thu. May 20, 2021 - 10:57 AM
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Try make a small temporary project, set this pin to push-pull in it and see in code preview what code is used by START to make this setting.

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Nafai
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This reply has been marked as the solution. 
Posted by Nafai: Thu. May 20, 2021 - 02:23 PM
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Thank you for the suggestion.  I discovered that what was happening was this line was forcing the gpio to go into an input mode even though I used the pin commands to make it go to output mode

 

adc_async_enable_channel(&ADC_0, CONF_ADC_0_CHANNEL_7);

 

So to solve the problem I do the following when I want to use the pin in output mode:

 

adc_async_disable_channel(&ADC_0, CONF_ADC_0_CHANNEL_6); //disable the channel so we can use output mode
gpio_set_pin_direction(AD0, GPIO_DIRECTION_OUT); // set output mode
gpio_set_pin_level(AD0, true); //set output to hi
gpio_set_pin_function(AD0, GPIO_PIN_FUNCTION_OFF); //not sure this is needed

 

Then to go to input mode so the AD can use the pin I do this:

 

adc_async_enable_channel(&ADC_0, CONF_ADC_0_CHANNEL_7); //enable the pin as an input to the AD
gpio_set_pin_direction(AD1, GPIO_DIRECTION_OFF); //set pin as analog input

 

This all seems to work. 

 

 

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Bronze Markawneil
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Posted by awneil: Thu. May 20, 2021 - 05:06 PM (Reply to #3)
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Nafai wrote:
This all seems to work. 

Thanks for reporting back.

 

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