Read PIN input value without using gpio_read() in Iotdk

[ericwu13]

Issue Summary

• Type: Question
• Category: Device HAL
• Priority: High
• Release Version: Specified version such as 2016.05 or All

• BOARD Iotdk

  Question

  Hi, I wonder if there a simple codes to read pin value without calling gpio_read function. Since if we have to call gpio_read function, the processor would need to allocate a stack for the function, do another of unnecessary things. If there is a way like AVR that accesses the PIN by the below.

I want to have a faster pin access time in IOTDK. Thanks.

uint8_t input_value = PIND&4 // get the input value of pin number 2 at port D

[IRISZZW]

when you use the gpio_read function, you will finally call _lr( (unsigned)(dev->reg_base + EXT_PORTA) );//(gpio.c) for example，PIN GPIO_8B0_3: dev->reg_base = AR_IO_GPIO_8B0_SWPORTA_DR = 0x80017800;//(dfss_gpio_obj.c) #define EXT_PORTA (0x50) /* GPIO External Port A Register *///(gpio.c)

so, you can do it:

uint8_t input_value = _lr(0x80017850) & (1 << 3); //pin num 3 at gpio_8b0

before read, make sure you have done the initial for pin.

[ericwu13]

Thanks. The speed is significantly increased. But instead of using _lr, which will cause linking error (I think I just didn't include needed header files for it), we can use the below without doing any modification to include statements:

uint8_t value = _arc_aux_read(0x80017850) & (1 << 3) // read pin num 3 at gpio_8b0