This chapter is obsolete ! See PIOS from Root Home.

USITT DMX 512 ./. Mac

The demonstration application for the device. Like all other manufacturers you can see the values and set them. Source is provided AS IS , without any damned warranty, for your trials.

You can download the latest application from the download page.
I have a lot of other specialized apps on the shelf which are only deployed in a custom built to order manner.

Cause as a serious developer I definitely cannot deploy them as a "Mac-Application" because they are not. They are tools running on a Mac - intended to be a part of a upcoming Mac-appl. Even if they come close to the usual Mac behaviour.

Picks from the shelf would be :

Sending text over the DMX line to propagate cues via DMX.
custom table headings for displaying human readable information (like a desk)
of course customizable morse (you have to proof the charity point for this one)
recording dmx along other QuickTime Tracks to play it back
multiple patching coming up with more interfaces
drag receive to throw in cuefiles in USITT ASCII

The source is also available so that you can comile your own appl to do more trials.

Keep in mind that there are the usual gotchas on the machine still present. The driver always will run cause it is in the system. But if your appl does not get WNEvents cause you switched it to the background or start other applications - your appl (and the demonstration appl also) will halt for a moment cause the Mac system multitasking is not giving it time ! So the best effort in these days of cheap mass storage is to run the dmx stuff on a dedicated clean Mac OS 9 as the only application.
By the way : If you have a G3 or better you can do a lot of other stuff while running the demonstration appl... but you have to trust the machine that only the screen drawing is slowed down. Look at the jumping counter values which do not increment by 1.

in medias res

This is how a window looks. Receiver and Transmitter are the same.

The stats on the bottom tell you the possible measurements.
Line 1:
STATUS is explained in dmx512.h and handles the drivers tasks. Usually it changes faster than drawing occurs.
RUNMODE is also from dmx512.h and tells you what the driver is doing. If you switch in the mode menu this value changes.
The following two values are the framecounters of the device. Useful if you receive low data rates. Sending is done always at full rate (by the device).
Line 2:
txst, rxst are the actual startcodes the device operates on.
txsl, rxsl are the number of channels the device gets and sends. This is useful to see how many slots (aka channels) are transmitted.
TX / RX are the memorypointers in the Mac RAM. If you have some other tools these are the addresses to look/work at.
Line 3:
time tells you the time the driver is running. Based on this all the calculations are done.
txmac / rxmac are the counters of the driver how many times a full dmx frame was transferred between the Mac and the device. These can vary from the devices counters cause of system load. Usually the Mac is faster.
txfps / rcfps dev are the average frames per second of the device based on the above mentioned time.
Line 4:
txfps / rcfps Mac are the average frames per second the Mac transfers between the device and Mac. If the Mac is set to non blocking mode (refer to USBDMX Device docs) these can go up to 70Hz. Which is just wasted processing power. In blocking mode the transfers are blocked until finished. Then these stay below the rates of device, naturally, cause the Mac now waits for the device.
Copies is the counter of the copies from receiver memory in ram to transmitter memory in ram. This does not slow down any other action. This is a driver function that is neccessary to safely put the device into a dmx line. Cause if you cut the line and place a USBDMX device in the line you have to copy over the data fast enough. So that fades are still fades. Of course you can do this copy also by the appl - but if you halt the Mac by the user interface with something like a menu no more copies happen... So it is better to let the driver do.
If the copy counter counts backwards the driver is using the Copy resource from the driver file.

For completeness here are the screenshots of the menus..

Special considerations
This appl is intended to be more a measuring / controlling / limiting thing than something where you can control intelligent light with cues and so on. This has to be done by your app. This app shows you (like other manufacturers) only that the device is working and gives you a starting point to develop your own lighting desk appl. Or you buy mine.

Typically you place the Mac after the desk to see what's going on on the dmx line and perhaps limit something or lock out channels. This is why the appl uses the drivers functionality to copy from receiver to transmitter - which is not needed if the Mac is the desk. In this case your data would be overwritten with the received data !
Also keep in mind that if you use the blocking mode and your desk sends slow data (30Hz or less) the Mac is blocked with waiting (in the driver) and fading can be problem. This happens cause of the drivers cycle to poll the incoming data, wait and then push the outgoing data into the device; And then be waiting for the next incoming dmx frame.

Application use
Slight easy. It's a Mac !
You can click on a channel in the tx-window. A single click increments this channel by 1. If you shift-click the channel is incremented by 10. If you command-click the channel is decremented by 1. And last but not least : option-clicking toggles a channel between full and off. Option clicking on a channel that has a value greater than 0 will turn it off. Option clicking a channel that is 0 will bring it 255.

For more information about programming or purchasing the USB2DMX Interface please refer to Information on how to get an Apple Computer with usb should be obvious.

Please note that I only develop software for a device that is built by someone else. This means I do not sell this equipment, neither I do the support for it. I only bring it to the MacOS.
USB2DMX Device Download Page ; read the licence agreement and then download the software to let your Mac talk to your lighting gear. Enjoy !

Ask me for different versions or drivers for other interfaces. I do custom-built-to-order.

Copyright : All rights reserved Hado Hein, 2001-2002, Berlin, Fed.Rep of Germany.