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I am considering using EPM7128 to implement SN74ACT8990,which is a
JTAG TAP controller.And the work is so hard and interesing.Is it
possible what I do?Are there VHDL code has been implemented JTAG TAP
controller?

Hi Bruce,

I am interesting to know if you have a full description of the SN74ACT8990.

Since I am working on a USB2.0 JTAG emulator, I would be able to write
the VHDL code of the SN74ACT8990 very quickly if I know the complet
description of the SN74ACT8990.

Regards,
Laurent
www.amontec.com

Bruce Sam wrote:
> I am considering using EPM7128 to implement SN74ACT8990,which is a
> JTAG TAP controller.And the work is so hard and interesing.Is it
> possible what I do?Are there VHDL code has been implemented JTAG TAP
> controller?
>

Hi Laurent,
SN74ACT8990 is linked
here:http://www-s.ti.com/sc/ds/sn74act8990.pdf.

Bruce Sam wrote:
> Hi Laurent,
> SN74ACT8990 is linked
> here:http://www-s.ti.com/sc/ds/sn74act8990.pdf.
>
There are no way to write VHDL code with the sn74act8990.pdf.
The sn74act8990.pdf is not a complet description of sn74act8990, but
only a description of the device interface. All other things you need to
describe VHDL register level of the sn74act8990 is skipped in the
sn74act8990.pdf. With sn74act8990.pdf you are using a black-block.

Larry
www.amontec.com

Sorry Laurent,I haven't a full description of SN74ACT8990.So I
think my original work is wrong and should be stop.Thanks you apply.

Laurent Gauch <> wrote in message news:<>.. .
> Bruce Sam wrote:
> > Hi Laurent,
> > SN74ACT8990 is linked
> > here:http://www-s.ti.com/sc/ds/sn74act8990.pdf.
> >
> There are no way to write VHDL code with the sn74act8990.pdf.
> The sn74act8990.pdf is not a complet description of sn74act8990, but
> only a description of the device interface. All other things you need to
> describe VHDL register level of the sn74act8990 is skipped in the
> sn74act8990.pdf. With sn74act8990.pdf you are using a black-block.
>
> Larry
> www.amontec.com

Does the specification helps ? IEEE1149.1

Wong wrote:

> Laurent Gauch <> wrote in message news:<>.. .
>
>>Bruce Sam wrote:
>>
>>>Hi Laurent,
>>>SN74ACT8990 is linked
>>>here:http://www-s.ti.com/sc/ds/sn74act8990.pdf.
>>>
>>
>>There are no way to write VHDL code with the sn74act8990.pdf.
>>The sn74act8990.pdf is not a complet description of sn74act8990, but
>>only a description of the device interface. All other things you need to
>>describe VHDL register level of the sn74act8990 is skipped in the
>>sn74act8990.pdf. With sn74act8990.pdf you are using a black-block.
>>
>>Larry
>>www.amontec.com
>
>
> Does the specification helps ? IEEE1149.1

No, it doesn't
-> because the sn74act8990 is a JTAG controller with internal register,
shift-register ...

Thanks,Laurent.I'm reading IEEE1149.1 now.

Thanks, Laurent.I'm reading the specification now.

[reneske]

Hi Laurent Gauch

Did yuo ever managed to implemented the 74act8990 JTAG TAP controller in VHDL.

I have this information, can that be used to make it?


search with google "act8990_users_guide.pdf"

Best regard
Rene E
reneske at gmail dot com