EXAMPLE
Example 1. An example usage in VMUSBReadout
Consider that you are running VMUSBReadout and want to add control the configuration and readout of a module completely throw low-level scripts. To do so, you would specify all of the logic in a set of scripts. The code to configure the module for readout might be in a file called init.tcl, the code for specifying how to read the module out would be in a file called event.tcl, and the code to shutdown the module's readout mode would be in a file called end.tcl. You would start by creating a daqconfig.tcl that has the following contents.
lappend auto_path [file join $::env(DAQROOT) TclLibs]lappend auto_path $::env(DAQLIB) package require cvmusb package require cvmusbreadoutlist package require readoutscript
readoutscript mydriver -controllertype vmusb
mydriver configure -initscript [file join /path to init.tcl] mydriver configure -rdolistscript [file join /path to event.tcl] mydriver configure -onendscript [file join /path to end.tcl] addtcldriver mydriver
stack create evtStack stack config evtStack -modules [list mydriver] -trigger nim1
- The first two rows ensure that the cvmusb and controlscript package can be found. This assumes that the DAQROOT and DAQLIB environment variables point to the NSCLDAQ installation of you choosing.
- Here we need to require the packages that might be used. The cvmusb and cvmusbreadoutlist packages are necessary in order to manipulate the Globals::aController or Globals::aReadoutList objects. We also need to require the controlscript package so that we can use it.
- An instance of the readoutscript snit::type is instantiated and configured. It is told that it is dealing with the VMUSB device and also where the required scripts are located.
- The instance of the readoutscript snit::type is not actually useful until we turn it into a Tcl driver. That is accomplished with the addtcldriver command.
- Now that we have the driver configured, we can add it to the stack for use. If it is not added to the stack, it is useless and is ignored by the Readout program.
For the init.tcl file, the logic will be extremely simple. I am going to assume that there is only one register to write to put the device into a state that suitable for data taking. Of course this is absurd and a real example would require a bit more than writing one register. Here we assume that writing 1 to a register at address 0xa2020100 using A32 single data access (0x09) is sufficient. We will also check via a read that it got set appropriately.
set ctlr $::Globals::aController
# write, read, and then check the value
$ctlr vmeWrite16 0xa2020100 0x09 1
set newValue [$ctlr vmeRead16 0xa2020100 0x09]
if {$newValue != 1} {
puts "ERROR! Write did not successfully set the value in the module"
}
Next we want read out the device when a trigger arrives. Let's assume that involves a block read with 34 transfers from address 0xa202000 and then a write to reset it. For the block read we need to use the 0x0b address modifier because the device is accessed using A32 addressing. We will also add some markers to bookend the data for easy identification. Here is what that would look like in the event.tcl file.
set stack $::Globals::aReadoutList
$stack addMarker 0xabcd
$stack addBlockRead32 0xa202000 0x0b 34 ;# 32 transfer BLT
$stack addWrite32 0xa20200200 0x09 1 ; # clear the module for a new event
$stack addMarker 0xbbcd
Finally, the end.tcl script is going to be used to take the device out of acquisition mode. Let's assume that this is accomplished in a manner that is opposite to what was done in init.tcl. So instead of writing a 1, we are going to write 0. Here is the end.tcl file:
set ctlr $::Globals::aController
# write, read, and then check the value
$ctlr vmeWrite16 0xa2020100 0x09 0
set newValue [$ctlr vmeRead16 0xa2020100 0x09]
if {$newValue != 0} {
puts "ERROR! Write did not successfully set the value in the module"
}