DSA interface hassle

borges · 15th September 2006, 05:02 PM

Hi,

I've just got my hands on a Philips L1210/65 CD drive. I've coded up the basics of a DSA interface in C for the Atmel ATmega48 MCU. I'm planning to release the code when it all works.

Right now I have some initial problems that I can't really figure out. I'm able to send quite a few DSA commands to the drive, but there are some obvious ones that fail.

For example I can send 0x0101 to play track number 1 and 0x0103 to play track number 3. In both cases the information I get back from the drive makes sense (Index, Abs.minutes, Abs.seconds). I can skip to track 3 while playing track 1, and to track 1 while playing track 3. But the weird thing is that I'm not able to tell the drive to start playing track 2. It continues there on its own when playing track 1, but I'm not able to instruct it to go to track 2. Neither am I able to tell the drive to stop.

When I send it an instruction it doesn't like (like 0x0102 to play track 2), the drive fails to give a communications ack at the end of the 16 bits. And after that it gives me the error code 0x042B which I can't find in the documentation.

When I try reading the TOC for session 0 (0x0300) I get the same error, 0x042B. I also got the error 0x0429 for a while, but it stopped saying that after I added some pauses in the DSA.

Any help on this would be great! Cabling, voltage supplies etc. seem to be in order.

Regards,
Borge

borges · 15th September 2006, 05:22 PM

Getting a bit closer here now...

I can write a DSA command that ends with a '1' but not one that ends with a '0'. Looks like it's back to the drawing board for now.

Have a great weekend!

Borge

borges · 15th September 2006, 05:38 PM

Sorry to have bothered you! Got it solved now. It was just me forgetting to set D back to 1 as I set S to 1 during the DSA signalling routine.

Borge

ZERS · 15th September 2006, 07:48 PM

Do you plan to post your C code soon ?

borges · 17th September 2006, 02:04 PM

Hi Zers,

Yes, I plan to post it fairly soon. Before releasing it I'll probably implement all the common CD player buttons. When it's out I will not have time to do much support on it. I'll also reread the DSA specifications to make sure that I write farily correct commands, not just what happened to work in the lab last night :-)

Are you in need of DSA code right now? I code for an Atmega48 on a veroboard that I program from an STK500 board using the WinAVR package.

Regards,
Børge

ZERS · 18th September 2006, 07:08 AM

Quote:

Originally posted by borges
Hi Zers,

Yes, I plan to post it fairly soon. Before releasing it I'll probably implement all the common CD player buttons. When it's out I will not have time to do much support on it. I'll also reread the DSA specifications to make sure that I write farily correct commands, not just what happened to work in the lab last night :-)

Are you in need of DSA code right now? I code for an Atmega48 on a veroboard that I program from an STK500 board using the WinAVR package.

Regards,
Børge

Hi,

I don't need it right now and on top of that I will use a PIC as controller. But the idea is top understand (by reading C code) how to deal with this interface. Because of my english, I've still got problems to understand several points. And I'm pretty much comfortable with reading C

15th September 2006, 05:02 PM	#1
borges diyAudio Member Join Date: Dec 2003 Location: Oslo, Norway	DSA interface hassle Hi, I've just got my hands on a Philips L1210/65 CD drive. I've coded up the basics of a DSA interface in C for the Atmel ATmega48 MCU. I'm planning to release the code when it all works. Right now I have some initial problems that I can't really figure out. I'm able to send quite a few DSA commands to the drive, but there are some obvious ones that fail. For example I can send 0x0101 to play track number 1 and 0x0103 to play track number 3. In both cases the information I get back from the drive makes sense (Index, Abs.minutes, Abs.seconds). I can skip to track 3 while playing track 1, and to track 1 while playing track 3. But the weird thing is that I'm not able to tell the drive to start playing track 2. It continues there on its own when playing track 1, but I'm not able to instruct it to go to track 2. Neither am I able to tell the drive to stop. When I send it an instruction it doesn't like (like 0x0102 to play track 2), the drive fails to give a communications ack at the end of the 16 bits. And after that it gives me the error code 0x042B which I can't find in the documentation. When I try reading the TOC for session 0 (0x0300) I get the same error, 0x042B. I also got the error 0x0429 for a while, but it stopped saying that after I added some pauses in the DSA. Any help on this would be great! Cabling, voltage supplies etc. seem to be in order. Regards, Borge

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15th September 2006, 05:22 PM	#2
borges diyAudio Member Join Date: Dec 2003 Location: Oslo, Norway	Getting a bit closer here now... I can write a DSA command that ends with a '1' but not one that ends with a '0'. Looks like it's back to the drawing board for now. Have a great weekend! Borge

15th September 2006, 05:38 PM	#3
borges diyAudio Member Join Date: Dec 2003 Location: Oslo, Norway	Sorry to have bothered you! Got it solved now. It was just me forgetting to set D back to 1 as I set S to 1 during the DSA signalling routine. Borge

15th September 2006, 07:48 PM	#4
ZERS diyAudio Member Join Date: Jan 2004 Location: LYON	Do you plan to post your C code soon ?

17th September 2006, 02:04 PM	#5
borges diyAudio Member Join Date: Dec 2003 Location: Oslo, Norway	Hi Zers, Yes, I plan to post it fairly soon. Before releasing it I'll probably implement all the common CD player buttons. When it's out I will not have time to do much support on it. I'll also reread the DSA specifications to make sure that I write farily correct commands, not just what happened to work in the lab last night :-) Are you in need of DSA code right now? I code for an Atmega48 on a veroboard that I program from an STK500 board using the WinAVR package. Regards, Børge

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