Read GPIO pin status through a characteristic.

Question

Hi, 
 I am new to nrf and trying to make some new services and characteristics for my device.
I followed the advertising , services and characteristics tutorial and was successfully able to make a new service and new characteristic. 
 But now I want to read the status of my D5 pin(P0.28 in nrf51822) using the same characteristics. I tried a lot of things but still not able to do so. 
 I am not getting what to change and where to change so that the particular GPIO is readable from the characteristic.
Please help me.
Thanks.

Jørgen Holmefjord · Accepted Answer

If you followed the characteristics tutorial to the end, you should have a characteristics reporting temperature gathered from the IC at a regular interval. If you want to change the application to report state of a pin on this charactersistics instead, this is the changes you need to make: 
 
 
 Define the pin: #define INPUT_PIN 28 
 
 
 Configure pin as input in main(): nrf_gpio_cfg_input(INPUT_PIN , NRF_GPIO_PIN_NOPULL); 
 
 
 Change timer_timeout_handler() function to read pin state and pass this to the characteristic update function: 
 
 
 
 static void timer_timeout_handler(void * p_context)
{
 int32_t pin_state = 0;
 pin_state = nrf_gpio_pin_read(INPUT_PIN);
 our_temperature_characteristic_update(&m_our_service, &pin_state);
 nrf_gpio_pins_toggle(BSP_LED_2);
}
 
 
 The characteristics should now be updated with the pin state on any change. 
 If you want the characteristics to be only 1 byte long, and also report the correct pin state on initialization, you also have to change the following: 
 
 In our_char_add() , change attr_char_value.max_len , attr_char_value.init_len , value and attr_char_value.p_value to: 
 
 
 attr_char_value.max_len = 1;
attr_char_value.init_len = 1;
uint8_t value = nrf_gpio_pin_read(INPUT_PIN);
attr_char_value.p_value = &value;
 
 
 
 In our_temperature_characteristic_update() , change len to 1. 
 
 Best regards, 
 Jørgen

Read GPIO pin status through a characteristic.

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