The problem : TLV320AIC codec outputs no audio on the Audio Ports after power on initialization. this happens only on may be 300th to 400th power cycle
Part No:TLV320AIC24
DSP used to interface: TMS320VC5470
TLV320AIC24 codec interface.pdfAttached is the schematics for codec interface with tms320VC5470 DSP
The I2C lines are not used and are just wired .
Before i go deep into the issue
I have couple of doubts as below ( datasheets weren't so clear around this area),Please clarify
- Is ACD used only for host port addressing or its even used for mcbsp bus?
- Page 14 of the datasheet depicts a timing ,now if master clk is 4 Mhz and sclk is 1 Mhz ,i wasn't too much suspecting the timing part of MCBSP Bus, as we would have enough margins due to the fact that data is received and sent on different edges (one at negative and one at positive).is my understanding correct?
- if the answer to question 1 is yes(i.e ACD is also used for MCBSP communication )then Page 14 of the datasheet says reset should be synced wrt to mclk ,would this mean u44 on the schematics should be triggered at falling edge of mclk for assuring setup and hold time for the reset pulse to be on safer side to overcome the possible timing violation due to flight time difference between MCLK and sampled reset signal by u44 at arrival point of codec
- On page 24 under the section "System Reset and Power Management" what does "during which the serial port of the DSP must be 3-stated."mean is it about the host interface or the MCBSP lines?
- what is the state of audio outputs on power up ,are they mid point biased?,what could possibly make a situation that the audio output slowly ramps down to zero volts from a given voltage at the output(other than the output analog switch Turing off)?
- Is there a errata for this device (either published or non published)
One exercise worth mentioning out of 100s that we have done is that the issue gets resolved when we trigger a DSP reset keeping all powers healthy .this would boil down to the fact that re initialization of codec registers is bringing back the codec to life again .
One we start discussing i can share more info around this
Regards
Ezekiel
998662039