Why the data will be lost at 115200 baudrate

NTDEV
1

Dear All,

I have a ploblem about the usb to serial driver on win98,

The question is the data will be lost at 115200 baudrate,I have try to modify the read buffer but it does not give an impact to speed.The firmware writer said the firmware buffer is overrun at 115200 baudrate,so he complain my driver read speed is not enough fast.But I don’t know how to enhance my driver read speed.

If the firmware need to be modified or some thing wrong in my driver?

Any advise will be appreciated!

Best Regards,
Black

2

There is far too much information missing from your post to answer your question. How big is the hardware buffer in the device? How long does it take to get the data out of the buffer? Are you running on a system with a PIO hard disk that is very busy? How long does your driver take to return the data requested from the receipt of the read request until IO completion? Are you attempting to only transfer one byte at a time to the user program? Properly designed hardware and software should be able to handle speeds at least eight times faster than the 115200 baud you mention. You might have to go to USB 2.0 at those speeds, but not for 115200.

----- Original Message -----
From: Black Lee
To: NT Developers Interest List
Sent: Wednesday, April 16, 2003 2:29 AM
Subject: [ntdev] Why the data will be lost at 115200 baudrate

Dear All,

I have a ploblem about the usb to serial driver on win98,

The question is the data will be lost at 115200 baudrate,I have try to modify the read buffer but it does not give an impact to speed.The firmware writer said the firmware buffer is overrun at 115200 baudrate,so he complain my driver read speed is not enough fast.But I don’t know how to enhance my driver read speed.

If the firmware need to be modified or some thing wrong in my driver?

Any advise will be appreciated!

Best Regards,
Black

b??箷????vڵ?j???*???.?˛???m??֛???zf???y?ޞ?^??x"X???&

3

Thanks a lot for your advice,I will modify my driver and firmware to solve this problem.

----- Original Message -----
From: David J. Craig
To: NT Developers Interest List
Sent: Wednesday, April 16, 2003 10:43 PM
Subject: [ntdev] Re: Why the data will be lost at 115200 baudrate

There is far too much information missing from your post to answer your question. How big is the hardware buffer in the device? How long does it take to get the data out of the buffer? Are you running on a system with a PIO hard disk that is very busy? How long does your driver take to return the data requested from the receipt of the read request until IO completion? Are you attempting to only transfer one byte at a time to the user program? Properly designed hardware and software should be able to handle speeds at least eight times faster than the 115200 baud you mention. You might have to go to USB 2.0 at those speeds, but not for 115200.

----- Original Message -----
From: Black Lee
To: NT Developers Interest List
Sent: Wednesday, April 16, 2003 2:29 AM
Subject: [ntdev] Why the data will be lost at 115200 baudrate

Dear All,

I have a ploblem about the usb to serial driver on win98,

The question is the data will be lost at 115200 baudrate,I have try to modify the read buffer but it does not give an impact to speed.The firmware writer said the firmware buffer is overrun at 115200 baudrate,so he complain my driver read speed is not enough fast.But I don’t know how to enhance my driver read speed.

If the firmware need to be modified or some thing wrong in my driver?

Any advise will be appreciated!

Best Regards,
Black

b??箷????vڵ?j???*???.?˛???m??֛???zf???y?ޞ?^??x"X???&

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