Port Read Delay.

[Shahrear]

Hello,

i am using nrf52832. i am using 8 different pin as a 8-bit parallel port. 

in my process i have to read each bit from each pin then converting those bit  into byte.

like this its taking 14uS to finish a conversion. 

my question is : How can i read all 8 pin as a 8 bit-parallel port?

[Jørgen Holmefjord]

Hi,

How are you currently reading the pins? You can read the state of the entire GPIO PORT using the IN register.

Best regards,
Jørgen

[Shahrear]

This is how i read and convert. would you please point me a example. i only need those 8 pin not the all pin of nrf52832.

uint8_t data_in() {

uint8_t data[10], sum = 0, i, j = 7;
config_dataport_in();
data[0] = nrf_gpio_pin_read(M1);
data[1] = nrf_gpio_pin_read(M2);
data[2] = nrf_gpio_pin_read(M3);
data[3] = nrf_gpio_pin_read(M4);
data[4] = nrf_gpio_pin_read(M5);
data[5] = nrf_gpio_pin_read(M6);
data[6] = nrf_gpio_pin_read(M7);
data[7] = nrf_gpio_pin_read(M8);


for (i = 0; i <= 7; i++) {
sum = sum << 1;
sum = sum + data[j];
j--;
}
return sum;
}

[awneil]

How to properly post source code:

[Shahrear]

Thanks

[Shahrear]

if  i read entire gpio then i have to mask out those 8 bit from 32 bit,. it will five same clock time which i currently having now. what do you think? if i want to read large memory block this 14uS is a big issue.

[Jørgen Holmefjord]

If you want to read each pin individually, there is no function for reading multiple random pins in the nRF. You could probably reduce your code a bit, but if you configure the compiler to optimize your application for speed, this should not make much difference anyway.

By making sure the 8 pins are in range, you could read the entire port and mask it out, for instance if you read P0.24-P0.31:

uint32_t port_state = nrf_gpio_port_in_read(NRF_GPIO);
uint8_t pins_state = (port_state >> 24) & 0xFF;