PORTS Forum

Ports and Interfaces => Serial Ports => Topic started by: GlennP on May 14, 2012, 10:18:58 am

Title: USB comports take longer to respond?
Post by: GlennP on May 14, 2012, 10:18:58 am
Hi All,

I am writing some PC code to interface to a board we are developing. I have noticed an issue with the com ports that are on the USB bus but not on board (Com1, PCI etc). The Hardware ports respond instantly the USB take longer around a second or two. I have never seen this before with USB.  At this stage I am using a short between pins 2&3 (no hardware...).  This only seems to happen the first time the program is run (possibly setting port up?)
once it has done this, the response is the normal speed.  Is my PC heading south again? as I have never known this to happen before.

Glenn   
Title: Re: USB comports take longer to respond?
Post by: GlennP on May 14, 2012, 10:28:03 am
It appears to just the first time it connects, once the connection is made and data can be sent & received on it it starts acting normally?  In further poking around if found the ini file for this program was setting baud rate to 11520 not 115200 shouldn't this baud rate raise an error? It still is doing the wait for a period time. I can see the data on a serial port monitor being sent.  It can't be the port is being blocked as I am using ReadExisting() as it is a non-blocking method, I am using an event handler to avoid timer issues on differing machines.    I belive the adapter may be faulty!

Glenn
Title: Re: USB comports take longer to respond?
Post by: GlennP on May 14, 2012, 11:27:54 am
Confirmed! my bad  ;D