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Entry  Thu Aug 12 11:19:04 2010, kiwamu, Update, CDS, current status 
    Reply  Thu Aug 12 14:01:53 2010, josephb, Update, CDS, current status 
       Reply  Thu Aug 12 18:30:08 2010, kiwamu, Update, CDS, Re: current status 
    Reply  Tue Aug 17 02:07:11 2010, Yoichi, Update, CDS, DACs have correct number of channels 
Message ID: 3428     Entry time: Tue Aug 17 02:07:11 2010     In reply to: 3405
Author: Yoichi 
Type: Update 
Category: CDS 
Subject: DACs have correct number of channels 


- DACs 

  None of them are working although the computer can recognize that all three DAC cards are mounted.

  I think something in the IOP file and the model file may be wrong because this symptom looks similar to that of C1ISCEX we tested two weeks before ( see this entry ) 

  I have to fix it anyhow because the DACs are very necessary part for this damping test.

 Since we had a similar trouble with the DAC at CLIO, I checked if this problem comes from the same origin.

The origin of the problem we had was that although the board was sold as 16 channel DAC, the firmware was set to use only 8ch.

To see if this problem exist in the DAC boards of c1sus, I added the following code to the /cvs/cds/caltech/cds/advLigoRTS/src/fe/map.c

printk("DAC ASSC = 0x%x\n",dacPtr[devNum]->ASSC);

in the definition of mapDac() function.

This code prints the information of the ASSC (Assembly Configuration) register of the PMC66-16AO16 board as a kernel message at the start up time of the realtime code. You can check the message with dmesg command.

After the modification, I recompiled the c1sus and installed it.

make c1sus; make install-c1sus

After starting c1sus, I checked the dmesg. Then found that the ASSC register was set to 0x130006. To decipher this magic number, you have to consult with the manual of the DAC, which is available online.


The manual says the 17th and 18th bits of this number set the number of channels. Those bits are 11 for 0x130006. According to the manual, 11 means 16 channels are present. So it seems that the ASSC register is correctly set. In the case of CLIO, the ASSC register was 0x110003, meaning only 8 channels are present.

Unfortunately, the ASSC register was not the cause of the problem, but at least this possibility was checked.

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