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cenadius
Joined: 13 Mar 2010
Posts: 11
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| how to stop USB data transmission infinitely? |
 Posted: Sun Mar 14, 2010 6:21 pm |
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Hi, I am doing a project in which I need to transmit data from from computer through usb to RS232, and I test my project with Hyperterminal and a USB GUI.
When I transmit some word from USB GUI for example: abc, Hyperterminal there will receive abc permanently.....
Can someone pls help me figure out my problem? Below is my code:
| Code: |
#include <18F4550.h>
#fuses HSPLL,USBDIV,PLL5,CPUDIV1,VREGEN,NOWDT,NOPROTECT,NOLVP,NODEBUG
#use delay(clock=48000000)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)
#define USB_HID_DEVICE FALSE
#define USB_EP1_TX_ENABLE USB_ENABLE_BULK //turn on EP1(EndPoint1) for IN bulk/interrupt transfers
#define USB_EP1_RX_ENABLE USB_ENABLE_BULK //turn on EP1(EndPoint1) for OUT bulk/interrupt transfers
#define USB_EP1_TX_SIZE 2 //size to allocate for the tx endpoint 1 buffer
#define USB_EP1_RX_SIZE 33 //size to allocate for the rx endpoint 1 buffer
// Include the CCS USB Libraries. See the comments at the top of these
// files for more information
//
/////////////////////////////////////////////////////////////////////////////
#include <pic18_usb.h> //Microchip PIC18Fxx5x Hardware layer for CCS's PIC USB driver
#include <fypusb.h> //USB configuration and descriptors
#include <usb.c> //handles usb setup tokens and get descriptor reports
void main(void)
{
int8 datain[33];
int8 dataout[2];
char rcvstr[16];
int8 i;
usb_init(); //init USB
usb_task(); //usb interrupt
usb_wait_for_enumeration(); //wait from host PC
while (TRUE)
{
if(usb_enumerated()) //usb config
{
if (usb_kbhit(1)) //
{
usb_get_packet(1, datain, 64); //
for(i=0;i<16;i++)
{
rcvstr[i] = datain[i+1];}
printf("%s",rcvstr);
}
}
}
} |
Has USB got function to clear the received buffer?
Thank you very much. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19348
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| Posted: Mon Mar 15, 2010 9:36 am |
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Ignoring the USB, there are enormous problems with your printf....
You transfer a number of bytes from the USB buffer to your buffer. You then ask printf to print this buffer. Series of problems:
1) You have not put a null terminator in the data, so the printf, will print through memory, till it happens to hit a null.....
2) You print the buffer repeatedly.
The 'get_packet' function, returns how many characters it has transferred. You need to null terminate the buffer at this point.
Then you need to copy the buffer, and only print once _after_ the copy.
Realistically, if you are using kbhit, why not use the usb_getc function, which automatically returns one character?...
I think if you sort out the problems here, you may well find it all starts working.
Best Wishes |
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cenadius
Joined: 13 Mar 2010
Posts: 11
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| Posted: Sat Mar 27, 2010 10:20 pm |
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| Thanks, the problem was solved by clearing the usb buffer. |
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