X-Git-Url: http://git.code-monkey.de/?a=blobdiff_plain;f=manual%2Facquisition.txt;fp=manual%2Facquisition.txt;h=05d2c84c33663dc53fdc575afab20c62a8608696;hb=1894027b98640702a5229c4168c586df5f83a3af;hp=0000000000000000000000000000000000000000;hpb=39e047cffdbfdb6dd10f3367e600887553a89d74;p=pulseview.git diff --git a/manual/acquisition.txt b/manual/acquisition.txt new file mode 100644 index 0000000..05d2c84 --- /dev/null +++ b/manual/acquisition.txt @@ -0,0 +1,120 @@ +== Data Acquisition + +Working with PulseView follows a pattern: + +image::pv_nodevice.png[] +<1> Open a new session +<2> Select the device you want to work with: +<3> Click "Run" to acquire signal data (waiting for a trigger first if you set one) + +When you start PulseView and no sessions are restored from the last time you used it, it will +come up with a session that has the demo device selected. That way, you can get to know the +program even when you don't have any hardware to use it with. + +=== Device Selection + +The device selector offers two methods to choose the device to use. If you click on the small +arrow on the side, you see a list of devices PulseView has recognized. If the device you want +to use it listed, you can just select it here to use it. + +image::device_selector_dropdown.png[] + +If it's not listed, you'll need to scan for it first. Since most serial port and Ethernet +devices can't be auto-detected, this is usually required for those. +To do so, either choose the "Connect to Device" option from the list or click on the button +itself. You will see the following dialog: + +image::device_selector_scan.png[] + +First, you'll need to pick a driver that you want to use. In order to do this, you'll need +to know which driver is used to talk to the device. If you're unsure, you can either try the +driver which you think may fit best or you can check the wiki. For every supported device there's +a wiki page, showing you which driver is used. + +Once the driver has been chosen, you need to select the interface. Please be aware that USB +is only usable for devices that directly communicate over USB. Devices that use USB to emulate +a serial port (like the OpenBench Logic Sniffer) will have their serial port listed in the +serial port drop-down. + +In case your device connects via Ethernet, you must supply the IP address and port. You are +also given the option to choose between raw TCP access and using the VXI protocol. VXI is an +industry standard which is mainly used in professional equipment and the device will most +likely let you know that it supports VXI. If your device however is more of a hobbyist grade +device, it's more likely that using raw TCP will be the correct choice. + +After you selected the appropriate options, clicking the scan button will make PulseView try +to connect to the device with the given settings. If successful, any device(s) found will be +shown in the list box. + +[NOTE] +When a session uses a USB device and you close Pulseview, a session with that same device +is re-opened when you start Pulseview again. Currently, this is however not the case for non-USB +devices, such as ones that connect via serial port or Ethernet. + +[NOTE] +To avoid having to manually enter the device configuration for a serial port or Ethernet +device every time you want to use it and then having to scan for it, you can also use the +command line parameter -d to have PulseView scan for it on startup. + +=== Device Configuration + +In PulseView, the device configuration is done using these buttons: + +image::pv_device_config.png[] +<1> Device-specific settings +<2> Channel-specific settings +<3> Number of samples to capture +<4> Sample rate at which to capture the samples +<5> Per-channel trigger setting (see below) + +The values offered for those four elements depend on your device. Which settings you should choose +depends on several factors: the needs of your measurement, the device you use to capture the data +and the capabilities of your computer. + +The sample rate you choose must at least be twice that of the highest frequency you want to +capture - ideally 3 to 5 times as much so that you have some margin. That way, a jittering signal +won't ruin your measurements. + +[NOTE] +If you're using a device with a Cypress FX2 (most 8 channel / 24 MHz logic analyzers do) then you should +be aware that the 24 MHz sampling rate (12 MHz for 16 channels) can only be sustained under perfect +conditions. Usually, those devices are shipped with low-quality USB cables, impairing USB transfers as +USB traffic increases. Therefore, you can try a different USB cable if you're facing issues at higher +sample rates. If they persist, it's worth trying a different USB port as well. + +=== Triggers + +The signal labels on the left side of the view (D0, D1 and so on in the picture above) allow you to +configure certain aspects of these signals. If the device supports it then the trigger that will be +used for this signal will be among them. + +As of now, the trigger system is awaiting extension for advanced and complex trigger types, meaning +that the only triggers available to you are: + +* Trigger when the signal has a "low" level +* Trigger when the signal has a "high" level +* Trigger when the signal switches from "low" to "high" level (rising edge) +* Trigger when the signal switches from "hig" to "low" level (falling edge) +* Trigger when the signal changes level in any way (any edge) + +Once you choose a trigger, the icon for the type you chose becomes visible on the right side of the +trace view. + +When you click "Run" with a trigger configured, PulseView will wait for the device to trigger and +send data before it can show anything. There is currently no frame limit, so if the device driver +supports it, PulseView will continue arming the trigger and collecting data until you either click +"Stop" or it runs out of memory. + +=== Channel Groups + +Some devices share certain settings between a group of channels, which is why PulseView may show +the channels your device offers in groups. You can see which channels are grouped by looking at the +dark gray bar on the left. If there is none, no channels are grouped. + +Currently, the grouping is only done for your convenience and there's no direct functional impact. +This means that you're free to ungroup and group channels as you please. To do so, right-click +on the dark gray bar and select "Ungroup". +If you want to create a new group, select the signals you want to group by holding down CTRL +and clicking on the signal labels. Once you have selected the ones you want to be grouped, +right-click on one of the labels you selected and choose "Group". +