#include "nrf_delay.h"
#include "nrf_gpio.h"
#define SETB(x,y) (x|=(1<<y)) //for o/p
#define CLRB(x,y) (x&=(~(1<<y))) //for o/p
#define TGLB(x,y) (x^=(1<<y)) //for o/p
#define CHECKB(x,y) (x&(1<<y)) //for i/p
#define SERIAL_BUFFER_SIZE 256
typedef struct
{
volatile unsigned char buffer[SERIAL_BUFFER_SIZE];
volatile unsigned int head;
}ring_buffer;
ring_buffer rx_buffer;
ring_buffer tx_buffer;
void UARTE0_UART0_IRQHandler(void)
{
int boo;
if(NRF_UARTE0->EVENTS_ENDTX == 1)
{
NRF_UARTE0->EVENTS_ENDTX = 0;
}
if(NRF_UARTE0->EVENTS_TXDRDY == 1)
{
NRF_UARTE0->EVENTS_TXDRDY=0;
}
if(NRF_UARTE0->EVENTS_TXSTARTED == 1)
{
NRF_UARTE0->EVENTS_TXSTARTED = 0;
//NRF_UARTE0->TXD.PTR=(uint32_t)&tx_buffer.buffer[0];
}
}
void uart_init()
{
NRF_UARTE0->BAUDRATE = 0x01D60000;
//NRF_UARTE0->CONFIG = 0x00000001;
NRF_UARTE0->PSEL.RTS = 5;
NRF_UARTE0->PSEL.TXD = 6;
NRF_UARTE0->PSEL.CTS = 7;
NRF_UARTE0->PSEL.RXD = 8;
nrf_gpio_cfg_output(6);
nrf_gpio_cfg_input(8, GPIO_PIN_CNF_PULL_Disabled);
nrf_gpio_cfg_output(5);
nrf_gpio_cfg_input(7, GPIO_PIN_CNF_PULL_Disabled);
NRF_UARTE0->EVENTS_ENDTX=0;
NRF_UARTE0->EVENTS_TXDRDY=0;
NRF_UARTE0->EVENTS_TXSTARTED=0;
//NRF_UARTE0->TASKS_STARTTX = 1;
//NRF_UARTE0->TASKS_STARTRX = 1;
NRF_UARTE0->INTENSET |= (1<<20)|(1<<8)|(1<<7)|(1<<2);
NRF_UARTE0->ENABLE = 0x00000008;
NVIC_EnableIRQ(UARTE0_UART0_IRQn);
}
void serial_write_irq(unsigned char c)
{
int i = (tx_buffer.head + 1) % SERIAL_BUFFER_SIZE;
tx_buffer.buffer[tx_buffer.head] = c;
tx_buffer.head = i;
}
void serial_write_string(char *pointer)
{
tx_buffer.head = 0;
while(*pointer!='\0')
{
serial_write_irq(*pointer);
pointer++;
}
NRF_UARTE0->TXD.PTR=(uint32_t)&tx_buffer.buffer[0];
NRF_UARTE0->TXD.MAXCNT=tx_buffer.head;
NRF_UARTE0->TASKS_STARTTX = 1;
nrf_delay_ms(1); // I am talking about this delay.
//If I removed this, serial terminal receives Garbage values.
}
void serial_no(long int n)
{
char c;
char buf[8 * sizeof(long) + 1]; // Assumes 8-bit chars plus zero byte.
char *str = &buf[sizeof(buf) - 1];
unsigned long int m;
*str = '\0';
if(n<0)
{
n=-n;
serial_write_string("-");
}
do
{
m = n;
n /= 10;
c = m - 10 * n;
*--str = c < 10 ? c + '0' : c + 'A' - 10;
} while(n);
serial_write_string(str);
}
int main(void)
{
int foo=-1000;
NRF_P0->DIR |= 0x0001E000;
NRF_P0->OUTSET |= 0x0001E000;
NRF_P0->PIN_CNF[11]=0x0000000C;
uart_init();
while(1)
{
NRF_P0->OUT^=0x00002000;
serial_write_string("Hello World ");
serial_no(foo++);
serial_write_string("\n\r");
//nrf_delay_ms(100);
if(CHECKB(NRF_P0->IN,11)==0)
{
serial_write_string("Button Pressed !!\n\r");
NRF_P0->OUT &= ~(1<<16);
while(CHECKB(NRF_P0->IN,11)==0){}
NRF_P0->OUT |= (1<<16);
foo=0;
}
}
return(0);
}
This is working code for UARTE using interrupts. But I am not able to understand that if I removed nrf_delay_ms(1) from function serial_write_string() then this code does not work.
After removal of nrf_delay_ms(1), it sends garbage values on serial terminal.
