Thread: Uart interrupt triggers after one keystroke

Can someone explain to me why i can only take in a single keystroke from hyperterminal/putty for the embedded program pasted below (main.c and retarget.c) before the ISR triggers.
Ultimately I would like to take in and store a larger number than a single digit.
I have tried increasing the size of ch[16], i understand that this is the input array size but i can only get it working with 16, is this because an integer is 16 bits?

The hardware is arm m0 based and the uart is implemented in hardware(memory mapped)

Code:

//------------------------------------------------------------------------------
// main.c
//------------------------------------------------------------------------------


#include <stdio.h>
#include <time.h>
#include <rt_misc.h>
#include <stdlib.h>


#define AHB_LED_BASE				0x50000000
#define AHB_UART_BASE				0x51000000




void UART_ISR(void)
{
			int sample;
			char ch [16];
			sample = atoi (ch);
			printf("the value entered is %d\n", sample);
}


//////////////////////////////////////////////////////////////////
// Main Function
//////////////////////////////////////////////////////////////////


int main() {
	
	{
		char ch [16];
		fgets (ch, 16, stdin);
	}
}

Code:

#include <stdio.h>
#include <time.h>
#include <rt_misc.h>


#define AHB_LED_BASE				0x50000000
#define AHB_UART_BASE				0x51000000
 
#pragma import(__use_no_semihosting)


struct __FILE { 
	unsigned char * ptr;
	};


FILE __stdout = 	{(unsigned char *)	AHB_UART_BASE};
FILE __stdin = 		{(unsigned char *)	AHB_UART_BASE};


int fputc(int ch, FILE *f)
{
  return(uart_out(ch));
   
}


int fgetc(FILE *f)
{ 
 	return(uart_in());
}


int ferror(FILE *f)
{
  return 0; 
}


int uart_out(int ch)
{
	int* UARTPtr;
	UARTPtr = (int*)AHB_UART_BASE;
	*UARTPtr = (int)ch;
	return(ch);
}


int uart_in()
{
	int ch;
	int* UARTPtr;
	UARTPtr = (int*)AHB_UART_BASE;	
	ch = *UARTPtr;
	uart_out(ch);
	return((int)ch);
}


void _ttywrch(int ch)
{ 
  fputc(ch,&__stdout); 
}


void _sys_exit(void) {




	while(1); 
	
}

apologies, i edited just before you posted that. Bit cheeky of me! haha. So define the array size and loop fgets till the array is filled?

Even in the case of a buffered UART, the input interrupt will be asserted when ever there's one or more characters in the input buffer. For output the output interrupt will be asserted whenever there is space in the UART's output buffer, so it's normally disabled by software until one or more output characters have been transferred to the UART, in which case it's enabled, then for each interrupt, another character is output from an interrupt processed software buffer or if that buffer is empty, the transmit interrupt is disabled. A separate status bit usually needs to be polled to determine when all character's in the UART's transmit buffer have been transmitted.