One thing to be aware of is that USB-serial adapters require conversions on both ends, serial-to-USB & USB-to-serial. This can be a factor in time critical applications. IOW, 9600bps will not be a true measure of throughput. I have encountered problems with some bootloaders when using USB-serial and, also, with ethernet-serial adapters. Also, while not a factor here, some USB adapters do not handle all of the modem control lines like DTR, etc.
I'm not sure what you mean hereOriginally Posted by dhouston
-Bert
The glass is not half full or half empty, Its twice as big as needed for the job!
http://foamcasualty.com/ - Warbird R/C scratch building with foam!
I use these with ny laptops.
http://www.tripplite.com/en/products...xtModelID=2430
As long as the signal is inverted, either by software or hardware it will work.
Dave
Always wear safety glasses while programming.
I like these...http://www.byterunner.com/byterunner...ct_match=exact. They work with Windows, Linux and OSX. You need drivers for Windows & OSX.
About half the cost too.
Thanks!!!
Dave
Always wear safety glasses while programming.
not normally this dense
Well maybe I am, but I don't know if I know more now or less. Heres where I have stumped myself.
Now the 3311 inverts the signal, so should I not use it if I am using the 232 to usb? Or does the cable take care of this? I would stupidly expect the 232 to usb cable to send/receive proper usb signals on the usb side and proper 232 signals on the 232 side.
This sounds like daveH post.
-Bert
The glass is not half full or half empty, Its twice as big as needed for the job!
http://foamcasualty.com/ - Warbird R/C scratch building with foam!
When going to a PC, the serial signal needs to leave the hardware inverted(PIC and components). Does not matter if you are going to a regular serial port or using a USB to serial converter.
The PIC, if using the hardware ports "HSEROUT" sends a TRUE signal so the MAX is needed for the inversion.
If bit-banging, "SEROUT2", then you can invert in PIC software.
Dave
Always wear safety glasses while programming.
Thanks guys
I think I have enough to get in trouble with now. I am off to put my test circuit together and start talking (or not).
-Bert
The glass is not half full or half empty, Its twice as big as needed for the job!
http://foamcasualty.com/ - Warbird R/C scratch building with foam!
I doubt it's a factor here but...I'm not sure what you mean here
On the PC end your serial signal gets converted to USB before it's transmitted. When received at the adapter it is converted from USB back to serial and then passed to the PIC. If your link is bidirectional the same conversions take place on signals from your PIC to your PC. At 9600bps, it's not much of an issue but at higher bit rates it can be significant. I've seen firmware downloads to an MCU that took 5 or more times as long over a USB-serial-adapter vs. a straight serial link. In some cases the download failed because the supervisory software didn't receive an ACK within the expected time. This can be even more pronounced over ethernet-serial adapters if there is heavy network traffic.
As I noted, it's just something to be aware of so you won't be scratching your head should you encounter it.
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