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5 years, 6 months ago.
How works gpio_init for the targets Nordic nRF5x?
I don't understand how the GPIO initialization is working when considering the following:
The function void gpio_init(gpio_t *obj, PinName pin) is resetting the configuration for all pins.
nrf_drv_gpiote_init()
...
for (i = 0; i < NUMBER_OF_PINS; i++)
{
pin_in_use_clear(i);
}
1 Answer
5 years, 5 months ago.
Hi David,
We have edited your question to include code tags to improve its readability.
The constructors for DigitalIn and DigitalOut will call gpio_init(), which in turn will call nrf_drv_gpiote_init() for the nRF52 targets. We can see your concern, but you might not have noticed this portion of the function:
if (m_cb.state != NRF_DRV_STATE_UNINITIALIZED)
{
err_code = NRF_ERROR_INVALID_STATE;
NRF_LOG_WARNING("Function: %s, error code: %s.",
(uint32_t)__func__,
(uint32_t)NRF_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
Only on the first pass through the function will the initialization take place. On subsequent calls m_cb.state equals NRF_DRV_STATE_INITIALIZED (from line 252), so no initialization will be performed as the function will return prematurely.
Hopefully that satisfies your concern.
Regards, Ralph, Team Mbed