Unable to Write AD1881A registers | Analog Devices DSPs

Dear all, I am encountering a problem to write AD1881A registers. I had posted this before. I could able to read the codec registers; but unable to write to it. I tried to communicate the codec at AC'97 mode. I am copying my earlier post at the end for your easy reference. We tried the CODEC in slot-16 mode, at this mode the codec is working fine. At the application note (Interfacing the ADSP-21065L SHARC DSP to the AD1819A AC'97 Sound Port Codec - http://www.analog.com/UploadedFiles/Application_Notes/250806129AD1819A _21065L.pdf ), the AD was mentioned that; it is needed to write successively to Serial Configuration register(0x74) for changing the CODEC from AC97 to slot16 mode. So I tried successively write some other value (0x1000 � not enabling the slot 16 mode) to this register; and it was successful (I read back). So it was possible to write to the serial configuration register at AC97 mode. But still then i was not able write any other register at AC'97 mode. In another attempt I tried successive write to the Volume Control Register to 0x0000 (just after the codec � DSP link established; the same method as the serial configuration register writing). But it was not successful. Is any problem for working the Codec at AC'97 mode while connected to a SHARC processor? What are the use of MODE pin and the CS0 and CS1 pins (I found very little information about these pins)? Please give me some direction to solve this problem. Thanks in advance. regards ajith Previous Post: I am working on a custom designed board with ADSP 21065L and AD1881A (AC'97 rev 2.1 complaint) CODEC. The interface is same as the AD1819-21065L interface provided by Analog Devices. The CODEC generates the BIT_CLK and in return DSP generates the SYNC. I probed these things by using CRO. I am facing a problem while writing to the CODEC registers. I am able to read the CODEC registers, but I am unable to write to the registers. i have done a CODEC initialization on another board in which ADSP 21065L processor is connected to the TLV320AIC27 CODEC. In this case i could read and write to the CODEC registers. Give some hints for possible causes. Does this AD1881 needs some specific register initialization before it starts initializing AC97 specific registers? I am specifically asking about the serial configuration registers and the miscellaneous control bit registers. Please note that I wish to work AD1881A in AC97 mode; not in slot16 mode. Set one register and then read back, and then sets another one; is this sequence works? What is the Codec register write latency? CS0, CS1 and MODE pin are left floated in our design. Is it has any effects on CODEC initialization? In AD1881 data sheet these pins are left unconnected, and there is only little information for these pins. But in AD1819 Codec, it is mentioned that CS0 and CS1 are tied to HIGH for single Codec application. Does any layout issues or power supply cause this kind of problems (Consistently able to read from the registers and unable to write on it. I checked the power down control status register; it shows that all the 4 subsections are ready)? Is anybody experiences similar problem? Please give me some hints for solve this problem. Thanks.

(You need to be a member of adsp -- send a blank email to adsp-subscribe@yahoogroups.com )

Sign in

Search adsp

Subscribe to adsp

adsp by Keywords

Discussion Groups

Discussion Groups | Analog Devices DSPs | Unable to Write AD1881A registers

Unable to Write AD1881A registers - ajith_pc - Mar 9 17:20:00 2004