Re: [Libusb-devel] Problems with re-opening USB-device

[Soumen M. <ms...@so...>]

The code you have posted uses D2XX direct driver APIs from FTDI, and not 
the APIs from LIBUSB as you have mentioned. I guess you need to paste 
the program which uses LIBUSB.

Thanks,
Soumen

David Hooker wrote:

>What error do you get when it fails to open the device?
>
>-----Original Message-----
>From: lib...@li...
>[mailto:lib...@li...]On Behalf Of Spippo
>Sent: Friday, July 27, 2007 6:26 AM
>To: lib...@li...
>Subject: [Libusb-devel] Problems with re-opening USB-device
>
>
>
>Hi all,
>
>I'm using LibUSB in Linux (Ubuntu 7.04) and trying to write a driver for
>serial USB communication.
>While writing this, I've come upon a problem:
>
>When I run my program, it finds the USB-device, opens it, configures it, ...
>, writes to the device and closes it.
>But when I run it again, it can't open the device anymore. I have to pull
>out the USB device, insert it again and then run the program.
>
>Here is my code:
>
>#include <stdio.h>
>#include <stdlib.h>
>#include <string.h>
>#include "ftd2xx.h"
>
>FT_HANDLE ftHandle;
>FT_STATUS ftStatus;
>
>UCHAR OUTPUTS = 0xff;
>UCHAR Mode = 0x1;
>
>char TxBuffer[8] = {'s','a','k','i','y','a','m','a'};
>DWORD BytesWritten;
>
>void USB_open();
>void USB_close();
>
>int main(int argc, char *argv[])
>{
>	int i=0, j=0;
>	
>	USB_open();
>
>	ftStatus = FT_Write(ftHandle, TxBuffer, 8, &BytesWritten);
>	if(ftStatus != FT_OK)
>		printf("Failed to write\n");
>        else
>	        printf("Write one char\n");
>	
>	USB_close();
>
>	return 0;
>}
>
>void USB_open()
>{
>	ftStatus = FT_Open(0, &ftHandle);
>	if(ftStatus != FT_OK)
>		printf("Can not open device\n");
>	else
>		printf("Device open\n");
>	
>	ftStatus = FT_ResetDevice(ftHandle);
>	if(ftStatus != FT_OK)
>		printf("REset device failed\n");
>	else
>		printf("Reset device ok\n");
>	
>	ftStatus = FT_SetBaudRate(ftHandle, 9600);
>	if(ftStatus != FT_OK)
>		printf("Setting baudrate failed\n");
>	else
>		printf("Baudrate set\n");
>
>	ftStatus = FT_SetBitMode(ftHandle, OUTPUTS, Mode);
>	if(ftStatus != FT_OK)
>		printf("Failed setting bit mode\n");
>
>	ftStatus = FT_Purge(ftHandle, FT_PURGE_RX || FT_PURGE_TX);
>	if(ftStatus != FT_OK)
>		printf("FT_Purge failed\n");
>}
>
>void USB_close()
>{
>	ftStatus = FT_ResetDevice(ftHandle);
>	if(ftStatus != FT_OK)
>		printf("Reset Device Failed\n");
>	else
>		printf("Device reset\n");
>
>	ftStatus = FT_Close(ftHandle);
>	if(ftStatus != FT_OK)
>		printf("closing failed\n");
>	else
>		printf("device closed\n");
>}
>
>I have tried some things to help it:
>- set the bitmode as synochronized : FT_SetBitMode(ftHandle, OUTPUTS, 0x04);
>- reset the bitmode (before i set it, and before i close the USB) :
>FT_SetBitMode(ftHandle, OUTPUTS, 0x00);
>
>Both these methodes solved the problem of re-inserting the USB, but then I
>couldn't send any data.
>
>Is there any way to solve this?
>
>
>Greetz
>
>Tim
>  
>