Hello all,
I'm currently working a student project using TMS320C6713 DSK to
create a voice-controlled toy car. I am looking for a way to generate
DC control signals with this board to control the car motors. I have
attempted to use the line out port for this, but the board has AC
coupling to remove DC signals from the output. I've looked through the
reference sheets, but was unable to find any sort of variable DC
output from the board. If anyone knows of a way to generate DC
signals from the board, or if there is a daughter card for this
purpose, it would be very helpful.
Thank you.
Using the TMS320C6713 DSK for DC voltage control
Started by ●April 5, 2007
Reply by ●April 5, 20072007-04-05
Euthoff-
> I'm currently working a student project using TMS320C6713 DSK to
> create a voice-controlled toy car. I am looking for a way to generate
> DC control signals with this board to control the car motors. I have
> attempted to use the line out port for this, but the board has AC
> coupling to remove DC signals from the output. I've looked through the
> reference sheets, but was unable to find any sort of variable DC
> output from the board. If anyone knows of a way to generate DC
> signals from the board, or if there is a daughter card for this
> purpose, it would be very helpful.
Ok, so you're an EE student and you're wondering how to convert an AC signal to DC...
can't you just short across the ac coupling caps and see if that works? You should
have the schematic in your DSK card documentation. Of course handle the card
carefully, disconnect from power before soldering and/or adding test clips, etc. As
an EE you should know this stuff already. If you don't have an ESD bracelet + wire,
then touch a PC chassis, and from that point don't move your feet.
Take initiative :-)
-Jeff
> I'm currently working a student project using TMS320C6713 DSK to
> create a voice-controlled toy car. I am looking for a way to generate
> DC control signals with this board to control the car motors. I have
> attempted to use the line out port for this, but the board has AC
> coupling to remove DC signals from the output. I've looked through the
> reference sheets, but was unable to find any sort of variable DC
> output from the board. If anyone knows of a way to generate DC
> signals from the board, or if there is a daughter card for this
> purpose, it would be very helpful.
Ok, so you're an EE student and you're wondering how to convert an AC signal to DC...
can't you just short across the ac coupling caps and see if that works? You should
have the schematic in your DSK card documentation. Of course handle the card
carefully, disconnect from power before soldering and/or adding test clips, etc. As
an EE you should know this stuff already. If you don't have an ESD bracelet + wire,
then touch a PC chassis, and from that point don't move your feet.
Take initiative :-)
-Jeff
Reply by ●April 7, 20072007-04-07
Eric-
> Thanks for the quick response, but I don't think that I've made my
> situation clear.
> I don't think that the AC coupling can not be disabled as you
> suggested because, from what I understand, it is built into the
> McBsp. Also my teammate and I are not able to make changes to the
> board circuit because it is school property.
First, please always reply to the group. My job does not permit me to reply to individual requests unless it's an
online technical forum.
Second, McBSP has nothing to do with it. That's a digital interface, right? So how would a digital interface be
removing DC? Did you "enable" a highpass filter bit in a McBSP register? No. Did you apply an 80 Hz highpass filter
bit in your DSP code? No. What's your technical basis for saying that McBSP has something to do with ac coupling?
I'd like to hear it.
Third, just use test clips! Don't make any changes to the card. C'mon.
> Yes, I do know how to convert a signal from AC to DC, but that is a
> work around that we are trying to avoid. We are running short on
> time, and there are other parts of the project that require much
> greater attention. I was hoping someone in the newsgroup would have
> some specific knowledge of our particular DSK board that we were
> unaware of that could help us quickly generate DC control signals
> without having to do any special circuit work.
Eric you have a ways to go between school and real world. Work-arounds are the name of the game in engineering, you
never get what you want without tradeoffs. "Engineering is making what you want from what you have" (or something
similar) is a popular quote. The fastest and cheapest way to possibly fix your problem is to short those caps, don't
buy an extra card, don't look for other analog interfaces on the DSK (there are none). In the time you spent replying
to me, you could have already tried my advice and kept moving.
Having said the above, I think you guys are doing fine. You have no shortage of ideas, you're trying hard to solve
the problem, you're being careful and respectful of the entity you "work for", and you're seeking out help and doing a
good job of it. Keep going :-)
-Jeff
> On Apr 5, 2007, at 6:36 PM, Jeff Brower wrote:
>
>> Euthoff-
>>
>>> I'm currently working a student project using TMS320C6713 DSK to
>>> create a voice-controlled toy car. I am looking for a way to generate
>>> DC control signals with this board to control the car motors. I have
>>> attempted to use the line out port for this, but the board has AC
>>> coupling to remove DC signals from the output. I've looked through
>>> the
>>> reference sheets, but was unable to find any sort of variable DC
>>> output from the board. If anyone knows of a way to generate DC
>>> signals from the board, or if there is a daughter card for this
>>> purpose, it would be very helpful.
>>
>> Ok, so you're an EE student and you're wondering how to convert an
>> AC signal to DC...
>> can't you just short across the ac coupling caps and see if that
>> works? You should
>> have the schematic in your DSK card documentation. Of course
>> handle the card
>> carefully, disconnect from power before soldering and/or adding
>> test clips, etc. As
>> an EE you should know this stuff already. If you don't have an ESD
>> bracelet + wire,
>> then touch a PC chassis, and from that point don't move your feet.
>>
>> Take initiative :-)
>>
>> -Jeff
>
> Thanks for the quick response, but I don't think that I've made my
> situation clear.
> I don't think that the AC coupling can not be disabled as you
> suggested because, from what I understand, it is built into the
> McBsp. Also my teammate and I are not able to make changes to the
> board circuit because it is school property.
First, please always reply to the group. My job does not permit me to reply to individual requests unless it's an
online technical forum.
Second, McBSP has nothing to do with it. That's a digital interface, right? So how would a digital interface be
removing DC? Did you "enable" a highpass filter bit in a McBSP register? No. Did you apply an 80 Hz highpass filter
bit in your DSP code? No. What's your technical basis for saying that McBSP has something to do with ac coupling?
I'd like to hear it.
Third, just use test clips! Don't make any changes to the card. C'mon.
> Yes, I do know how to convert a signal from AC to DC, but that is a
> work around that we are trying to avoid. We are running short on
> time, and there are other parts of the project that require much
> greater attention. I was hoping someone in the newsgroup would have
> some specific knowledge of our particular DSK board that we were
> unaware of that could help us quickly generate DC control signals
> without having to do any special circuit work.
Eric you have a ways to go between school and real world. Work-arounds are the name of the game in engineering, you
never get what you want without tradeoffs. "Engineering is making what you want from what you have" (or something
similar) is a popular quote. The fastest and cheapest way to possibly fix your problem is to short those caps, don't
buy an extra card, don't look for other analog interfaces on the DSK (there are none). In the time you spent replying
to me, you could have already tried my advice and kept moving.
Having said the above, I think you guys are doing fine. You have no shortage of ideas, you're trying hard to solve
the problem, you're being careful and respectful of the entity you "work for", and you're seeking out help and doing a
good job of it. Keep going :-)
-Jeff
> On Apr 5, 2007, at 6:36 PM, Jeff Brower wrote:
>
>> Euthoff-
>>
>>> I'm currently working a student project using TMS320C6713 DSK to
>>> create a voice-controlled toy car. I am looking for a way to generate
>>> DC control signals with this board to control the car motors. I have
>>> attempted to use the line out port for this, but the board has AC
>>> coupling to remove DC signals from the output. I've looked through
>>> the
>>> reference sheets, but was unable to find any sort of variable DC
>>> output from the board. If anyone knows of a way to generate DC
>>> signals from the board, or if there is a daughter card for this
>>> purpose, it would be very helpful.
>>
>> Ok, so you're an EE student and you're wondering how to convert an
>> AC signal to DC...
>> can't you just short across the ac coupling caps and see if that
>> works? You should
>> have the schematic in your DSK card documentation. Of course
>> handle the card
>> carefully, disconnect from power before soldering and/or adding
>> test clips, etc. As
>> an EE you should know this stuff already. If you don't have an ESD
>> bracelet + wire,
>> then touch a PC chassis, and from that point don't move your feet.
>>
>> Take initiative :-)
>>
>> -Jeff
>
