README.devices: discuss ASIX OMEGA in RTM CLI mode (vendor application)

A stub sigrok driver can use the vendor's command line application to
make principal Asix Omega operation available. Outline the approach and
discuss the requirements for this setup in the README.devices file.

diff --git a/README.devices b/README.devices
index 3e9b631f75f9936708f5505e23499a47eeec0fe9..6d139aa9af0b88b31f7e8f028ed6a12f054abe84 100644 (file)
--- a/README.devices
+++ b/README.devices
@@ -32,6 +32,13 @@ Per-driver firmware requirements
 
 The following drivers/devices require a firmware upload upon connection:
 
+ - asix-omega-rtm-cli: There is no native sigrok support for ASIX OMEGA
+   devices. But the vendor's RTM CLI application can be used in streaming
+   mode, which transparently handles the device detection and firmware
+   download. The firmware ships with the vendor application. See below
+   for details how to make the vendor application available to the sigrok
+   driver.
+
  - asix-sigma: The ASIX SIGMA and SIGMA2 require various firmware files,
    depending on the settings used. These files are available from our
    'sigrok-firmware' repository/project under a license which allows us
@@ -438,6 +445,64 @@ a short list for convenience:
  - Voltcraft VC-870: Press the "REL/PC" button for roughly 1 second.
 
 
+ASIX OMEGA in RTM CLI mode
+--------------------------
+
+The asix-sigma driver can detect the Omega devices' presence, but does
+not support their protocol and emits a diagnostics message. The firmware
+image is not available for distribution, and information on the protocol
+is not available. That's why native support is in some distant future.
+Yet basic operation of Omega devices is available by using the vendor's
+command line application for real time mode (RTM CLI).
+
+The vendor application targets Windows (on x86), but also executes on
+Linux when 32bit libraries for FTDI communication are provided. The
+user manual discusses the installation. The sigrok asix-omega-rtm-cli
+driver uses the vendor provided omegartmcli.exe binary to configure the
+device for streaming, and to acquire sample data.
+
+Either make an "omegartmcli" executable available in PATH. This can be
+the vendor's executable or some wrapper around it or a symlink to it.
+Or specify the executable's location in the OMEGARTMCLI environment
+variable. The sigrok driver accepts an optional serial number (six or
+eight hex digits) to select one out of several connected devices.
+
+  (optional)
+  $ export "OMEGARTMCLI=$HOME/.wine/drive_c/progx86/ASIX/SIGMA/omegartmcli.exe"
+
+  (optional)
+  $ OMEGASN=":conn=sn=a6030123"
+
+  (example use)
+  $ sigrok-cli -d asix-omega-rtm-cli${OMEGASN} --show
+  $ sigrok-cli -d asix-omega-rtm-cli${OMEGASN} -o capture.sr --time 10s
+  $ sigrok-cli -d asix-omega-rtm-cli${OMEGASN} -o capture.sr --samples 100m
+  $ pulseview  -d asix-omega-rtm-cli${OMEGASN}
+
+The RTM mode of operation samples 16 channels at a fixed rate of 200MHz.
+Hardware triggers are not available in this mode. Glib should handle
+platform specific details of external process execution, but the driver
+was only tested on Linux so far. Acquisition start in sigrok applications
+may take some time before sample data becomes available (roughly one
+second here on a slow machine). This is an implementation detail of the
+RTM CLI approach including execution under wine.
+
+The reliability of that setup in the presence of fast changing input
+signals is yet to get determined. It's assumed that slow input signals
+are operational. It's essential that the _average_ rate of changes in
+the input signal in combination with the hardware compression are such
+that the FTDI FIFO can communicate all involved data via USB2.0 to the
+application. Intermediate bursts of rapid changes shall not be an issue
+given the Omega devices' deep memory which RTM uses for buffering.
+
+Native support for the Asix Omega devices depends on the availability of
+a protocol description and use of the protocol depends on the firmware's
+availability at the user's site. Which then would allow to capture to
+DRAM at high rates without the communication bottleneck, before the data
+gets communicated to the PC after the acquisition has completed. Compare
+the native sigrok supoprt for Asix Sigma.
+
+
 ChronoVu LA8/LA16 USB VID/PIDs
 ------------------------------