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Good day!
My target hardware consists of a TMS320C541 DSP
and a TLC320AD545 codec
connected in the standard synchronous serial
port this way.
------------------------------- ------------------------------
|
| | |
| DSP
| | CODEC |
| CLKR |
<--------------: | |
| CLKX
| <---------------:------------ | SCLK |
| FSR
| <---------: | |
| FSX
| <---------:------------------
| FS |
| DR | <---------------------------- | DOUT |
|
DX
| ----------------------------> | DIN |
------------------------------- -------------------------------
The DSP is operating at 40
MHz while the CODEC master clock is at 5
MHz.
(I connected the DSP TOUT pin to
the CODEC MCLK and I programmed
the timer interrupt rate to 5
MHz.)
I've initialized the serial port this
way.
TXM -> 1
; internally generated frame sync
MCM -> 0 ; clock taken from pin FSM -> 1 ; burst mode: frame sync pulse required First problem: I'm trying to generate a
1800-Hz sinewave by using a lookup
table (with 256 samples). The analog
output of the codec is very distorted.
I've tried varying the amplitude of the
sinevalues and the increment of sample
(or the
sinestepsize). I've also connected a 2nd-order Butterworth lowpass
filter
in the codec output. But my analog signal is
still distorted.
Second problem: I've injected an
analog input (sinewave) in the codec. I've
tried varying both the frequency and the
amplitude of the sinewave.
But no receive interrupt is generated in the DSP. I noticed that
there
are signals in the DOUT, FS and CLK
lines.
Any help that you can extend will be gladly
appreciated.
Thank you.
Raquel B. David
Design Engineer
Micrologic Systems Inc.
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DSP and CODEC
Started by ●July 13, 2000
