This is the software support for the FPGA obs-box
DEPENDENCIES
============
You can find all the software dependencies as sub-module of this repository:
* fmc-bus : this is a carrier abstraction. It hides the differences between
carriers
* spec-sw : it is not a real software dependency because you can compile the
driver without this sub-module. But, this is the carrier of our
FPGA, then we need this piece of software to run our FPGA
* zio : the driver use this acquisition framework to simplify the I/O
operations
-------
ZIO <---> OBS-BOX <---> FMC-BUS <---> SPEC-SW <---> HARDWARE
-------
OBS-BOX CONFIGURATION
=====================
There are some sysfs attributes used for the driver configuration. Here I'm
showing only that attributes used by this driver. For the meaning of all
the other attributes please refer to the ZIO documentation.
channel-set 0
-------------
/sys/bus/zio/devices/obs-box-XXXX/cset0/
ob-run: 0 -> STOP acquisition, 1 -> RUN acquisition
ob-streaming-enable: 0 -> single shot mode, 1 -> streaming mode
trigger
-------
/sys/bus/zio/devices/obs-box-XXXX/cset0/trigger/
post-samples: number of samples to acquire for each block (page size). It can
be configured only when the acquisition is not running. You can
modify the value while the acquisition is running, but it will
be applied on reset (stop and start). For the time being you
gain the best performance with 2M page size.
ACQUISITION
===========
This is a ZIO driver, so refere to the ZIO documentation for the details.
Here a rapid overview
/dev/zio/obsbox-0-0-ctrl
/dev/zio/obsbox-0-0-data
With the first char device you read the control information. This file export
block of 512 byte at time (no more, no less). It contains the details about
the block of data ready on the second char device. In order to read it
correctly you have to use the zio_control structure from "zio-user.h".
struct zio_control ctrl;
...
read(fdctrl, &ctrl, sizeof(struct zio_control));
Within the zio_control there are some useful information. For a simple
acquisiton the number of bytes to read from the data char device
buffer = malloc(ctrl.ssize * ctrl.nsamples);
read(fddata, buffer, ctrl.ssize * ctrl.nsamples);
A good example is the zio-dump program. You can find its source file in:
zio/tools/zio-dump.c
DEDICATED TOOL
==============
obsbox-dump
-----------
This is a simplification of the zio-dump program. It just prints out the
data acquired from the device