Need to use Homework board .

Angela-Curti

Hi,

I need to connect the Homework board microcontroller but without the USB cable.

I need to connect the homework to my old computer using the old serial connection DB9 of the old computer.

I need help to know if it is possible to "jump" or distroy the USB circuit and transfom the USB Homework in to a DB9 Homework.

Please see the picture.

thanks.

Phil Pilgrim (PhiPi)

I think you'll have a problem without some extensive, tedious rework to the Homework board. It would be better to get a USB-port plug-in board for the old computer, assuming it's running an op system that supports USB. Is there a reason that you have to use that PC and not something newer?

-Phil

Angela-Curti

But I have and old homework that works very fine with the DB9.

And I would like to to something similar.

USB is not usefull for me.

Please help.

Phil Pilgrim (PhiPi)

There's more than just a connector involved. You also need an inverting level translator to convert the +/-12V RS232 values to +5V logic levels. Then you'll have to cut some tiny traces on the Homework board, carefully scrape off the green solder mask, and solder some very fine wires to them to connect the level translator. This is not a job for someone who's never done solder rework before; but if you're experienced, it's not insurmountable either.

-Phil

Publison

The Board of Education DB9 is still available:
https://www.parallax.com/product/28150
Of course you would have to add a BS2 to it:
https://www.parallax.com/product/bs2-ic

There is a cheaper board, but you would have to add the BS2 to it also:
https://www.parallax.com/product/27120
It is on sale.

I see you are in Chile, so shipping may be a problem.

Publison

When you say "old" computer, does it only have ISA slots, or does it have at least one PCI slot?

erco

I'm late to this party. I'm proud to own the very last box of serial HW boards that Parallax ever sold. Angela, where are you?

JonM

Couldn't you just use a USB to serial cable or converter to plug a USB Homework board into a DB9 serial port?

Maybe something like:
https://parallax.com/product/28030

Phil Pilgrim (PhiPi)

The Parallax board creates a serial interface from a USB host (i.e. the PC). The OP would need to create a USB host from a serial interface. That would take a different kind of module -- if they even exist.

-Phil

rosco_pc

Simple serial - TTL interfaces:
http://picprojects.org.uk/projects/simpleSIO/ssio.htm
http://forums.parallax.com/discussion/85344/simple-serial-interface-for-propeller-programming

Still needs to be connected to the lines requiring either the cutting of traces or the removal of some smd components in the USB circuit

erco

Still waiting for Angela to contact me and my big box of new serial HW boards.