Xue Lang-
> Hi everyone! I'm a newcomer on using TI DSP. Now
I'm working on a project
> that uses Tms320c6713 as argrithom computing unit, one ADC for acquiring
> signals, two DAC for outputing DSP's results. The ADC and DACs are on
one
> piece of circuit we designed. Tms320c6713 collets data from ADC and sends
> data to DAC all through EMIF interface. EMIF is mapped into CE2 space and
it
> is configued 16-bit asynchronous interface.
>
> We 've configured two Mcbsps as GPIOs to send out ADC and DAC's
control
> signals, the control signals meet our demands. They can be high or low
level
> where we need.
If the ADCs and DACs are connected to EMIF, then why do you need additional GPIO
signals? To what pins are the GPIO
signals connected?
> Because I am not familiar with DSP, when we designed
our circuit board,
> EMIF's CEn. AWE.ARE pins are all not conneted. So my first quesiton is:
can
> our design work? These EMIF's three pins MUST be conneted? I'm not
sure
> about it.
Well, you have to both read and write the ADCs/DACs, correct? Normally either
/AWE or /ARE is connected (usually just
one is needed). How do you plan to control the WR and RD signals on the ADC and
DAC chips? Using the GPIO pins?
That could work, but it's going to make your code very slow.
Also some general comment. Are you saying you left the /AWE and /ARE pins NC?
Or you brought the pins out to
test-points (via) on the board, so you can run a jumper wire if needed? If the
former, then I suppose you realize now
that the rule is "when in doubt, run a test point". In fact, in our lab, we run
*all* NC pins to TP if layout space
and other constraints will allow.
-Jeff
> Today when I debug DAC ( 12 bit), I use this
method:
>
> Firstly, write 0x100 16-bit data( each value is 0x0FFF) in program. These
> data are in L2 RAM.
>
> Secondly, send these data to DAC through EMIF in CE2 space, the first
> address is 0xA0000000. Because DAC is 12-bit, the LSB 12 bit is only
needed.
> If DAC is disconneted to DSP, I can observe 12 high leves about 3V using
> scope.
>
> Thirdly, running program to send out signlas to control DAC. Unfornately,
> when control signals and data are sent out, I watch memory in address
> 0xA0000000, the values are all 0x06600660. It's so strange!! The right
> values should be 0x0FFF0FFF. So the second question is : where does the
> wrong value come from? Is it related to EMIF's /AWE and /CEn pin?
>
> I hope anyone can shed some light on this or point me in the right
direction
> todebug this problem.
>
> With kind regards,
>
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