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Entry  Mon Jul 14 19:03:05 2014, Yves Bianga, change cascading from 1024 to 2048 bins for each input channel 
    Reply  Wed Jul 16 12:10:19 2014, Stefan Ritt, change cascading from 1024 to 2048 bins for each input channel 
Message ID: 359     Entry time: Wed Jul 16 12:10:19 2014     In reply to: 358
Author: Stefan Ritt 
Subject: change cascading from 1024 to 2048 bins for each input channel 

Yves Bianga wrote:

Hello,

 
I want to ask whether it is possible to modify a Evaluation Board 5.0 from 1024 to 2048 cells for each of the 4 input channels.
On the rev50 manual at page 31 I found an option to connect the 4 unused channels by setting 8 solder bridges.
The source code for controlling the board seems already prepared for 2048 bins, since version 5.0.2.
 
So my first question: Are there any implementations in the VHDL Code to control the write shift register in 2048 mode? / Is there a necessity for a newer/other VHDL Code or is it already implemented?
 
And the second: Are there any other modifications except the eight zero Ohm resistors and maybe changes in the FPGA code?
 
My board info output:
 
Mezz. Board index:    0
DRS type:             DRS4
Board type:           9
Serial number:        2451
Firmware revision:    21260
 
 
Thanks a lot!
 
Yves Bianga

Indeed you only need R99-R106 to be installed. Unfortunately the firm/software cannot know if the resistors are there, that's why we introduced R142/R143, which connect J44 of the FPGA optionally to low. So if J44 is low (R143 installed), this tells the system that we are in 2048 bin mode. Unfortunately you need firmware revision 21305 or later to support this bit, which you apparently do not have. So you can either upgrade the firmware (if you have a download cable) or "fake" the 2048 bin mode in software. Go to line 4345 of DRS.cpp and look for DRSBoard::Is2048ModeCapable(). This function just returns the status of this bit. If you installed R99-R106, you could modify this function to always return "1" instead of "0". Then the DRSOsc program will display 2048 bins for each of the four channels.

Best regards,

Stefan 

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