Unable to communicate through serial port

snip PC stuff

I would start off by using a terminal program on the PC, say terraterm, so that would rule out a problem on the PC side, and it would prove the cable is wired correctly

martin

Hi

Did you try to look if you have data transfert on your serial line ? May be for the PC side you should start to try with a serial instead of your untested code ? (like windows hyperterminal or better tera term) Re-read your controler datasheet or try to find application notes (often availble on chip manufacturer website. Re-read the datasheet part on serial controler but not only, look for example if you need to configure the pin as a serial line and not as a standard IO, etc.

Regards, Guillaume

What operating system on the PC? What you describe is the DOS way of doing it. Under Windows, the ports are controlled by Windows drivers.

Yes. And hold something shorting pins 2&3 of the PC cable (transmit looped back to receive) to verify that when you short them, anything you type is now displayed, or is being displayed twice if it was already being displayed once with the pins unshorted.

Also, if using hyperterminal make sure you set flow control to none.

Also, if using hyperterminal... don't. Use something reliable like teraterm. ;)

-- Grant Edwards grante Yow! I am a traffic light, at and Alan Ginzberg kidnapped visi.com my laundry in 1927!

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You haven't specified whether your board includes an RS-232 driver. If it does, does it require you to set or clear an enable pin for the driver?

I would also program a nice long (perhaps 100 millisecond ) delay loop between character sends. That will make it much easier to track down the problems with an oscilloscope.

Mark Borgerson

Yeah, but when a tool is so widely distributed, even if it's a very bad tool, it's worth knowing how to make it perform, because the day will come when you run into a situation where your preferred tool isn't available - co-worker's machine, customer on the phone, locked- down computer, won't let your laptop into the building, whatever.

It could be that the legacy serial port on your PC doesn't work properly. I'm having this problem literally right now as we speak.

My P4 desktop is fine, it's old and clunky, and it's fine. My Dell laptop just reads gibberish inbetween odd bits of sense. Ah, I hear you say, install a USBSerial dongle. Except it won't install as anything lower than COM5, due to the infraport spoof ports which are turned off in the BIOS yet are still found. That and the internal modem, again, which keeps on installing itself.

I'm using Termrite 1.5. It doesn't need installing and is 74KB in size. It's now running on a 486DX2-75 IBM 755C now used for RS232 data capture throughout this project.

I despair!! We've finally reached the age where the indestructable serial port doesn't work.

Aside from that lot it's probably your code but I don't code for the AVR so can't tell you. I can only tell you about what's up above.

"> The code for the board:

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Where is EI ? enable interrupts...timer won't run....

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Hi, I am trying to follow the books of Mazidi, to build this board and code also.

At the first glance I has not find the use of EI. I think I have to read more (In depth also). keep in touch.

thanks.

Windows XP is my operating system. is it the main problem?? I had tried by hyperterminal program first but failed too. thanks

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I am using MAX 232 chip with 22uF electrolyte capacitor, as it described on the 8051 Books of Mazidi and max 232 data sheets.

Waiting for your response.

This is very good idea I am trying it by today evening. thank you

Of course it will run. It just doesn't produce interrupts...

Meindert

I rarely use hyperterm in dev environment but I couldn't count the number of times its saved my arse in the field.. :)

Find out which end is failing first. Use a loopback on your PC (pin 2 connected to pin 3) and make sure PC is working. Once that is verified you know where to look.

I am fabricate the board for myself.

There are also times when you might have to use a cigarette lighter as a soldering iron. It might be better than nothing, but it's not exactly the tool of choice!

So the recommendation is to drop hyperterminal if you possibly can, and use something simple and decent like Tera Term. Hyperterminal *may* work, but why add more uncertainty to your problems?

To compare the usability of hyperterminal to the utility of a cigarette lighter as a soldering iron is rediculous. Compare it to some $4 soldering iron from radio shack. Not great, but easy to get a hold of and usually practical... even for SMD if you are really really careful.