Forums

How to check whether the HPI pins of 6713dsk is selected?

Started by xinxin1034 May 11, 2006
Now I think the problem of communication between 2407aEVM and 6713dsk
by using HPI is that the setting of HPI enable pin is not always
correct when 6713dsk reset. The HPI enable pin is HD14, it should
be '1' when the 6713dsk reset if I want to use HPI. But HD14 is
connected to D14 pin of 2407aEVM, so it is influenced by 2407 and not
always '1' during 6713 reset. Are there any methods to know whether the
HPI pins are enabled after reset? Many thanks!

Xinxin
Xin Xin-

> Now I think the problem of communication between 2407aEVM and 6713dsk
> by using HPI is that the setting of HPI enable pin is not always
> correct when 6713dsk reset. The HPI enable pin is HD14, it should
> be '1' when the 6713dsk reset if I want to use HPI. But HD14 is
> connected to D14 pin of 2407aEVM, so it is influenced by 2407 and not
> always '1' during 6713 reset. Are there any methods to know whether the
> HPI pins are enabled after reset? Many thanks!

2407 should not be driving its EMIF lines unless your 2407 code is
running. Otherwise, HD14 should be tri-state from 2407 and controlled by
pull-up/pull-down R on DSK C6713.

You cannot guess at this. You have to watch HD14 on dig scope. Use
rising edge of Reset to C6713 to trigger the scope, and verify that HD14
is correct level when Reset is de-asserted.

-Jeff
Many thanks for your reply.

When I swithed on the 6713, HD14 pin is always high. If 2407 is connected to 6713, and I switched on 6713 again, HD14 is nearly 1.5V.Then I switched on 2407 and did not load or run any code, the output of HD14 is a square wave. If I 2407 is disconnected to 6713 and switched on, the output of HD14 is a square wave as well. It looks like 2407 controlled HD14. If 2407 should not be driving its EMIF lines unless my 2407 code is running, How to explain such phenomena? I am very confused about that.

I will try your method to see what will happen.

Thanks again!

Xinxin

Jeff Brower wrote:
Xin Xin-

> Now I think the problem of communication between 2407aEVM and 6713dsk
> by using HPI is that the setting of HPI enable pin is not always
> correct when 6713dsk reset. The HPI enable pin is HD14, it should
> be '1' when the 6713dsk reset if I want to use HPI. But HD14 is
> connected to D14 pin of 2407aEVM, so it is influenced by 2407 and not
> always '1' during 6713 reset. Are there any methods to know whether the
> HPI pins are enabled after reset? Many thanks!

2407 should not be driving its EMIF lines unless your 2407 code is
running. Otherwise, HD14 should be tri-state from 2407 and controlled by
pull-up/pull-down R on DSK C6713.

You cannot guess at this. You have to watch HD14 on dig scope. Use
rising edge of Reset to C6713 to trigger the scope, and verify that HD14
is correct level when Reset is de-asserted.

-Jeff

Send instant messages to your online friends http://uk.messenger.yahoo.com
Xi Zhang-

> When I swithed on the 6713, HD14 pin is always high.

So this is what you want for normal operation, correct?

> If 2407 is connected to 6713, and I switched on 6713 again, HD14 is
> nearly 1.5V.Then I switched on 2407 and did not load or run any code,
> the output of HD14 is a square wave. If I 2407 is disconnected to 6713
> and switched on, the output of HD14 is a square wave as well. It looks
> like 2407 controlled HD14. If 2407 should not be driving its EMIF
> lines unless my 2407 code is running, How to explain such phenomena?

My guess would be 2407 is running a bootloader when it comes out of Reset, and the
bootloader is trying to determine whether to boot from serial port, EMIF, etc. When
it "queries" EMIF, you might see data and address lines toggling.

I think you may need a bus switch for critical HDn lines, and use an enable on the
bus switch. When the 2407 makes a *specific* access to the DSK C6713 -- when /CEn is
active, correct address lines are active, etc -- then the bus switch is enabled.
This will keep HD14 "disconnected" from the 2407 until the 2407 actually needs it,
and your DSK C6713 can boot correctly, whenever needed.

You have a daughterboard connected to 2407 EVM, right? And that cables to DSK C6713
HPI connector? Then you can put the bus switch on the daughterboard.

-Jeff

> Jeff Brower wrote:
>
> Xin Xin-
>
> > Now I think the problem of communication between 2407aEVM and 6713dsk
> > by using HPI is that the setting of HPI enable pin is not always
> > correct when 6713dsk reset. The HPI enable pin is HD14, it should
> > be '1' when the 6713dsk reset if I want to use HPI. But HD14 is
> > connected to D14 pin of 2407aEVM, so it is influenced by 2407 and not
> > always '1' during 6713 reset. Are there any methods to know whether the
>
> > HPI pins are enabled after reset? Many thanks!
>
> 2407 should not be driving its EMIF lines unless your 2407 code is
> running. Otherwise, HD14 should be tri-state from 2407 and controlled by
> pull-up/pull-down R on DSK C6713.
>
> You cannot guess at this. You have to watch HD14 on dig scope. Use
> rising edge of Reset to C6713 to trigger the scope, and verify that HD14
> is correct level when Reset is de-asserted.
>
> -Jeff
>
> Send instant messages to your online friends http://uk.messenger.yahoo.com
>
> +
>
> ------------
>