Set IO through a register

RE: Set IO through a register

Dmitry — Thu, 16 Sep 2021 11:41:32 GMT

As I understand, it's a low-resolution LCD with parallel interface? if so, I don't think you can get any speed boost with direct register writing.

liuyanfeng — Thu, 16 Sep 2021 09:51:18 GMT

I want to improve the driving capability of the 52840 drive LCD screen.

To make the LCD display faster, I defined each pin like this

# define RESET NRF_GPIO_PIN_MAP (0, 8)

# define CSP NRF_GPIO_PIN_MAP (0, 7)

# define RSP NRF_GPIO_PIN_MAP (0, 6)

# define WRP NRF_GPIO_PIN_MAP (0, 5)

# define RDP NRF_GPIO_PIN_MAP (0, 4)

# define RESET_H () nrf_gpio_pin_set (RESET)

# define RESET_L () nrf_gpio_pin_clear (RESET)

I want to set nrF_GPIO_pin_set (RESET) and NRF_GPIo_pin_clear (RESET)

Is it possible to increase the execution speed by switching to registers?

Or in assembly language?

static void SPI_WriteCmd8Bit( uint8_t CByte )

{

NRF_GPIO_Type *p_reg=NRF_P0;

uint32_t value=0;

RSP_L (); // NRF_P0-> OUTCLR = (1 < < RSP); This will stop the program from executing

RDP_H (); // NRF_P0-> OUTSET = (1 < < RDP); This will stop the program from executing

value = p_reg-> OUT;

value &= ~(0xFF< < 24);

value |= (CByte< < 24);

p_reg-> OUT = value;

WRP_L (); // NRF_P0-> OUTCLR = (1 < < WRP);

WRP_H (); // NRF_P0-> OUTSET = (1 < < WRP);

}

Can you help my mom?

Dmitry — Thu, 16 Sep 2021 09:19:59 GMT

Did you configure pin as output? Could you show your complete code?

liuyanfeng — Thu, 16 Sep 2021 09:09:07 GMT

My program won't run if I use it this way。 thank you all the same

Dmitry — Thu, 16 Sep 2021 08:42:06 GMT

Hi,

it should be straightforward - for example, set/clear bit 5:

NRF_P0->OUTCLR = (1 << 5);
NRF_P0->OUTSET = (1 << 5);