hi i am working with lpc1768 in usb host mode Initially I was open seven text files by fopen command Then write a string like "abcdefgh" by the fputs command within seven text files Before writing command first turn on one led and after seven write comman turn off led By measuring the time of high and low on led pin I realized that this time is the size of about two seconds. I want to know is why? Thanks for your help
Who wrote your USB code, who designed your board?
LPC1768 is a chip from NXP, it tells us nothing about your implementation using it.
Where does the code spend it's time? In a spin loop? Waiting for an interrupt?
i designed home made board with lpc1768 and writing code With the help keil example
//-------------------------------------------------------------------------- void UART2_IRQHandler(void) {
uint32_t intsrc, tmp, i;
uint8_t a;
/* Determine the interrupt source */
intsrc = UART_GetIntId(LPC_UART2);
tmp = intsrc & UART_IIR_INTID_MASK;
// Receive Data Available or Character time-out
if (tmp == UART_IIR_INTID_RDA)
{
a = UART_ReceiveByte(LPC_UART2);
if(a == 0)
f = fopen ("f.txt", "a");
f1 = fopen ("f1.txt", "a");
f2 = fopen ("f2.txt", "a");
f3 = fopen ("f3.txt", "a");
f4 = fopen ("f4.txt", "a");
f5 = fopen ("f5.txt", "a");
f6 = fopen ("f6.txt", "a");
}
else if(a == 255)
fclose (f);
fclose (f1);
fclose (f2);
fclose (f3);
fclose (f4);
fclose (f5);
fclose (f6);
else
strcpy (&in_line[0], "abcdefghijklmnopqrstuvwxyz\r\n");
fputs (in_line, f);
fputs (in_line, f1);
fputs (in_line, f2);
fputs (in_line, f3);
fputs (in_line, f4);
fputs (in_line, f5);
fputs (in_line, f6);
i = GPIO_ReadValue(1)&0x01000000;
if(i == 0)
GPIO_SetValue(1, 0x01000000);//led on
GPIO_ClearValue(1, 0x01000000);//led pff