Re: BasicX 24 Chip Hangs When USB-to-Serial cable unplugged then plugged

Started by Brad Watts April 14, 2009
The same thing can happen just by restarting Windows on XP machines. It
sounds like the ATN line is toggling when the USB dongle is connected. You
may need to disconnect the ATN line between the serial cable and the
processor to prevent this from happening

Here is the info from the manual:

Serial Port Connector

Once you've downloaded a program to the BX-24 chip, the development board's
DB-9 serial connector

may then be used for other purposes. If you do use the connector for
anything other than downloading

your program, you should remove Jumper 1 from the option header. By removing
Jumper 1 you

disconnect the BX-24's ATN line (pin 3) from the serial connector and avoid
accidentally putting the BX-

24 in download mode.

Listed below are the connections needed to add a DB-9 serial downloading
connector to your own BX-24

project.

DB-9

Connector BX-24 Chip

Pin 2 = TX >--------< Pin 1 of the BX-24

Pin 3 = RX >--------< Pin 2 of the BX-24

Pin 4 = ATN >--------< Pin 3 of the BX-24

Pin 5 = Ground >--------< Pins 4 or 23 of the BX-24

Brad



Hi Brad/Tom,

I just wanted to follow up and say thanks for your responses.

We don't want to disconnect the ATN line... so we're going to stick with adding a watchdog timer to reset the chip when/if it hangs. I am trying to look at this as a blessing in disguise because the watchdog code is probably handy to have. (who knows what other scenarios reset the chip)

You might also be interested to know that BX24p resets the chip on our breadboard after unplugging the USB cable (instead of just when it was plugged in after a reset with my BX24/dev station setup). Interesting to note.

-Trevor
--- In b..., "Brad Watts" wrote:
>
> The same thing can happen just by restarting Windows on XP machines. It
> sounds like the ATN line is toggling when the USB dongle is connected. You
> may need to disconnect the ATN line between the serial cable and the
> processor to prevent this from happening
>
>
>
> Here is the info from the manual:
>
>
>
> Serial Port Connector
>
> Once you've downloaded a program to the BX-24 chip, the development board's
> DB-9 serial connector
>
> may then be used for other purposes. If you do use the connector for
> anything other than downloading
>
> your program, you should remove Jumper 1 from the option header. By removing
> Jumper 1 you
>
> disconnect the BX-24's ATN line (pin 3) from the serial connector and avoid
> accidentally putting the BX-
>
> 24 in download mode.
>
> Listed below are the connections needed to add a DB-9 serial downloading
> connector to your own BX-24
>
> project.
>
> DB-9
>
> Connector BX-24 Chip
>
> Pin 2 = TX >--------< Pin 1 of the BX-24
>
> Pin 3 = RX >--------< Pin 2 of the BX-24
>
> Pin 4 = ATN >--------< Pin 3 of the BX-24
>
> Pin 5 = Ground >--------< Pins 4 or 23 of the BX-24
>
>
>
> Brad
>
>
>