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Entry  Sat Oct 15 04:45:25 2011, Aurelien Bouvier, DRS4 eval board: readout rate 
    Reply  Sat Oct 22 00:40:02 2011, Stefan Ritt, DRS4 eval board: readout rate 
Message ID: 133     Entry time: Sat Oct 22 00:40:02 2011     In reply to: 132
Author: Stefan Ritt 
Subject: DRS4 eval board: readout rate 

Aurelien Bouvier wrote:

Hi,

Our setup uses a DRS4 evaluation board (version 2.0).

Although we trigger the board at a rate of ~4kHz (on channel2), readout through USB2 is only happening at a rate of ~125Hz.

After some investigation, we could pin down that it is due to the time it takes to complete the following commands: musb_write() and musb_read() which both take ~150 microsecond to complete. Because they are called multiple times, reading out 1 trigger takes ~8 millisecond which explains the 125Hz we're seeing.

Is ~150 us to complete a musb_read()/musb_write() command expected?

Is there any way we could speed up the readout rate of the DRS4 board so that data acquisition through USB2 is closer to our trigger rate of 4kHz?

Any feedback you might have on this topic would be greatly appreciated.

Many thanks,

Aurelien

With version 4 of the DRSOsc program and a decent computer, you should be able to achieve something close to 500 Hz, but that's the limit. The board is for evaluation purposes of the chip, not for production data acquisition. The main limit comes from USB2, which is limited to ~25 MB/sec. We are in the process of designing a new board with Gigabit Ethernet readout, with which you should be able to get your 4 kHz. But this board will not be ready before spring. There is also a VME board by CAEN in Italy which sits in a VME crate. This board is also much faster than the USB board. Here is the link:

http://www.caen.it/csite/CaenProfList.jsp?parent=13&Type=WOCateg&prodsupp=home

 

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