How Can I Connect My Laptop to Microcontroller 8051 Development Board

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Problem understanding the rules?

If they cannot read the microcontroller manual for their help line, do you really think that they can read our rules?

you may say mr. I am sorry for that but I would like to bring the things in your knowledge that ,user mannual not given and I also tried a lot on internet.I have also mailed to technical support team of manufacture till now I did not got reply.

thanking you for your comment and wish....

I have had very bad luck in getting DB9 to USB adapters to work properly. If the USB port requires a power connection on it, it will not work with a DB9 adapter as they usually do not pass power though that port in my experience. Try a laptop with a USB port that you can connect to rather than through the DB9.

Most of the USB to DB9 (COM:) Port adapters will not work is such situations. It is a pretty well known problem, some do some don't.....

The one that has probably the best chance that I know of is this one here:-

http://www.picaxe.com/Hardware/Cables/PICAXE-USB-Download-Cable/

Though it contains only Data in, Data out and a ground connection, that is 3 pins only!!!

It was designed to fix such compatibility problems....

Usually other signals can be "linked" at some point to allow data flow, its an old trick and easy to do.....that may get the interface running as you wish......

If you need other signals as well from a COM: Port for this 8051 unit, then I would look either for a proper COM: Port interface card for your Laptop (depends upon your Laptop design/ports) with all signals, or even buy an older Laptop/PC with a proper COM: Port still in it......the unit you want to talk to may even accept say a really old PC/Laptop running DOS and a suitably old Text program, all available as free downloads on the web.

If I was picking a Laptop for such work, I would find one with Win98SE on it. Why you may ask? Simply because this supports USB ports for writing data on to memory sticks and other devices....so make sure that the laptop either also has USB ports or you can obtain an adapter card that will work with it, even though it will not work with your USB to COM: converter that you bought!!!

Or a laptop with a floppy/CD Burner drive and add a USB floppy drive to your present laptop. Some external CD Burners will work with it maybe.......all cheap secondhand on ebay.....mix and match will work......

Do some careful planning before buying......even an old PC may be a good purchase for such work.....they almost always have COM: Ports.

Which end is the DB9, and , which end is the USB?

microcontroller end is DB9 and laptop end is USB

Then you should be able to get it to work by configuring the USB port: see SHOCKHISCAN's answer #8 below.

If all else fails then a USB development board will be a lot cheaper than an old PC with RS232 interface.

Here's one for 1100 Rupees

http://store.extremeelectronics.co.in/Easy-8051-Development-Kit.html

You have a choice:
1. Acquire an old PC or laptop with a serial port.
2. Buy a development board for the 8051 series with a USB connection. they do exist:

http://www.silabs.com/products/mcu/Pages/C8051F340DK.aspx

You must configure the laptop comm port to the correct settings.

Parity, Comm rate/speed, checksum, etc.

Read all of the installation directions in the IOM and in the "READ ME" file.

If you do not have the information on installation disc nor in the in the IOM you will need to download it from the internet.

A USB to RS232 serial converter should work

http://www.digi.com/products/usb/edgeport

But only if the microcontroller software the OP has can be switched to the COM number of the USB connection. Many older software can only use COM1 or COM2 that are still dedicated to RS232 hardware ports on the motherboard, even though this hardware no longer exist on many computers.

Nice idea, but.....

Sadly, not all converters work in all situations......only purchase and a full test will demonstrate the effectiveness or not in different situations......there are no guarantees.....sadly!!

It has a greater chance of not working than working.....hopefully he gets lucky......

For example, all a PICAXE chip needs is serial data in, data out and signal ground, but even then, most versions of USB to COM converter simply do not work with PICAXE!!! Which is why they only guarantee their own (very cheap!) version to actually work!!

In the CNC world, there are (expensive) converters of USB to COM, but to get them to work, the speed gets really restricted of the Stepper motors, simply because a USB streams data and a true COM port doesn't!!! A COM port has very accurate timing, just what a CNC really needs......USB doesn't need accurate timing....it sends (and receives) data when it can.....difficult to handle in the X,Y,Z world!!

I personally favour the old laptop idea, with a REAL com port......but the OP will have to decide what he wants to do.....all by himself.

We have all given him good advice....