DMX Interface Card Hardware: this is a complete step-by-step description how to access the hardware, and how to set the working parameters required for DMX512/1990. Find memory maps, hardware addresses and other hardware-related stuff.
SOUNDLIGHT offers a range of PC interface cards, not only readily available but affordable and easy to program. Besides we offer ready-to use software packages for free.
Programming of our interface cards is really simple. Here are the few steps to get things running.
- very fast card, Clock = 16 MHz
- opto-isolated output driver (potential-free output)
- may read DMX data (for monitoring only)
- Memory Allocation of Interface Card 1512B:
$0000-$03EF DMX operating system, max. 1000 Bytes
$03F0-$03FE Operating System Parameters dmxdef()
$0400-$05FF Send Data for Channels 1-512
$0800-$09FF Receive Date for Channels 1-512
To initialize the card:
- Determine the card address.
To do so, use a routine as outlined below. In all examples we will assume a card address of $0100:
- Write $FF to card address $0100
- Write $03 to card address $0101 (0100 +1)
This sets the internal card RAM address to $03FF.
- Write $AA to card address $0102 (0100 +2)
- Read card address $0102 (0100+2)
- If the return value is $AA, the card is found.
- If not, repeat steps (1) thru (5) for addresses $0120,
- Transfer the DMX Operating System into the card,
to make the card operational.
Assume you are going to find a 1512B card in your (unknown) computer.
- Read card address $0100 to reset the card, then
- open the file SLHDMX16.BIN.
NOTE: Close this file before opening it. This ensures to never get a "file open"
error. Depending on the programming language used, you must open the file as BINARY or RANDOM
because all NULL bytes must be transferred exactly as read.
Then the file will be transferred into the card RAM. The card address must be known to do so.
- Set RAM-Adress = $0000
- Write the RAM-Address LowByte to Card-Address +0
- Write the RAM-Address HighByte to Card-Address +1
- Read the next byte from file and write it to Card-Address +2
- Repeat (3) thru (5) until EOF
We have now transferred the DMX operating system and are ready to start the card.
This will enable the card processor to check the card status and return a card identification byte.
- Read Card Address +3 to start the card and wait at least 50us to read the result.
- Write $F9 to Card Address +0
- Write $03 to Card Address +1
This selects the return byte RAM address $03F9 within the card RAM.
- Read Card Address +2
Return value $04: Card 1512C present
Return value $05: Card 1512C present
Return value $80: Card 1512A or 1512B/LC (12 MHz
Return value $01: Card 1512B (16 MHz Card) present
If a 1512B Card is identified the initialization is okay. f another card is being
identified the complete initailization procedure has to be repeated, using the proper
DMX operating system. Please use the following files:
SLHDMX12.BIN for card 1512A or 1512B/LC
SLHDMX16.BIN for card 1512B
SLHDMX17.BIN for card 1512C
After file transferral the retuirn value must be checked again. If the return value
matches none of the values listed above, either the card or the DMX OS transfer process
has shown defective. Return codes $06 to $1F are reserved for future SLH products.
- Transfer the Default Parameters into the card.
The DMX operating system files allow individual setting of channel count,
card timing an other parameters. If no or invalid parameters are set the card may
automatically set valid parameters instead.
Minimum Value: 88us
Value: n = Startsync * 2 / 3
|dmxdef(0) = 60|
for DMX Transmissions
|dmxdef(1) = 0|
|$03F2||End Idle Time (us)
n = (Idle Time - 30us) / 2
The minimum idle time after transmission of a complete DMX telegram is 30 us
|dmxdef(2) = 0|
|LowByte Channel Count|
HighByte Channel Count
LO: 001 HI: 000 1 channel sent
LO: 002 HI: 000 2 channels sent
LO: 003 HI: 000 3 channels sent
LO: 000 HI: 000 256 channels sent
LO: 001 HI: 001 257 channels sent
LO: 002 HI: 001 258 channels sent
LO: 255 HI: 001 511 channels sent
LO: 000 HI: 001 512 channels sent
LO = Channel Count AND 255
HI = INT ((Channel Count -1)/256)
|dmxdef(3) = 0|
dmxdef(4) = 1
$00: Send Once, then Stop (Recommended)
$80: (<>0): Send continuously
|dmxdef(5) = 0|
n = IDT * 16 / 24
optimum Value: 0
|dmxdef(6) = 0|
|$03F7||not used||dmxdef(7) = 0|
$00 = Write Mode
$FF = Read Mode
|dmxdef(8) = 0|
|$03F8||not used||dmxdef(8) = 0|
|$03F9||Card Type Return Value|
|dmxdef(9) = 0|
Now transfer the Default Parameter Values to the Card Data RAM:
- Set n=0
- Write $F0 + n to card address +0
- Write $03 to card address +1
- Write dmxdef(n) to card address +2
- n= n+1
- Repeat (2) thru (5) while n<10
Now the card is ready for use. Eventually you may want to erase the DMX data RAM.
To do so, simply write $00 to all remaining card RAM locations.
- Start the Card
After initialization and setting of the operating system parameters the card may start its first transmission.
To start the card, use the command:
- Read Card Address +3
According to the card mode set above one or more DMX telegrams will be sent.
- Transfer DMX data to the card
To transfer data to the card or read back data from the card) we highly recommend to use a timer.
This will ensure the best data integrity, since access to the card during transmission may corrupt send data.
Use a timer (timer repeat time >25 ms) to initiate the command sequence outlined below.
- Each write access to the card will stop the card CPU, which must then be restarted.
- After all memory updates heve been processed start the card to initiate e new DMX transmission.
- The card wil then complete the current DMX telegram an await the next data update.
- Write LowByte of DMX Channel to CardAddress +0
- Write HighByte of DMX Channel to CardAddress +1
- Write Value of DMX Channel to CardAddress +2
- Repeat (1) thru (3) for all channels that have to be updated
- Start the card by reading from CardAddress +3
|Base Address +0||Write Lo-Byte RAM-Address|
|Base Address +1||Write Hi-Byte RAM-Address|
|Base Address +2||Read Data||Write Data|
|Base Address +3||Start DMX Transfer |
S/W Access Table Base Address = $100, $120, $140 or $160
Any Write Access stops the DMX-Transfer
- SWITCH SETTINGS
Do not change switch settings unless required. The cards come with address $0100 (256 dec) set.
Switches 1 and 2 set the card's interface address
CARD ADDRESS $0100 (256 dec)
CARD ADDRESS $0120 (288 dec)
CARD ADDRESS $0140 (320 dec)
CARD ADDRESS $0160 (352 dec)
Switch 3 sets the card type identification. It MUST be set in accordance with the card's crystal frequency.
12 MHz CARD
16 MHz CARD
Switch 4 is for factory use only and must never be changed.
FREQUENTLY ASKED QUESTIONS / HOW TO .. ?
- I can't put the card to work.
All cards are fully checked prior to shipment. Of course any electronic component can fail, but in a computer system chances are that address, software or hardware conflicts exist. Please try one of our ready-to use programs first. Most of these programs show a clear identification of the card after initialization in a message box. Address, card type and/or frequency will be displayed. If the card cannot be found please check for an address conflict.
- OK, your program is running fine but the card does not respond to my program. It does nothing.
We have prepared several demos which are presented in our programming lessons. Use these demos as a skeleton for your own projects. Before the card can be used you must transfer the card operating system into the card. If bytes are transferred erroneously, missing or faulty the card will not work! For Beginners it is a good idea to read out the card contents after transferral to make sure everything is okay and matches the SLHDMXnn.BIN file's contents.
- A card was found but the wrong card type displayed.
Please check the card switch setting. SW3 must be set according to the card's crystal frequency to allow identification..
- I have a 1512C card and this cannot be identified when using the routines described above.
This is a shortcoming of the current SLHDMX12.BIN and SLHDMX16.BIN driver files, which have been written prior to the release of the 1512C card. Thus the drivers do not know this card type. New drivers will be released shortly. Please use the identification scheme as outlined on the 1512C page..
- What about drivers?
We supply DLL's which can be used with Windows 3.1/3.11 and Windows 95/98, respectively. Please check the drivers download area below to obtain the latest drivers available. A decription how the access the DLL functions is contained in the 1512B manual and every source code demo of our programming lessons. There you can also download a OCX control element to drive the cards.
- What is the difference to all the other cards you offer?
The original card was called 1512A. From this, we derived the 1512B, which is a reliable card for professional use. It features additional safety through optical isolation and runs at higher clock speed (16 MHz compared to 12 MHz). The 1512B-LC (Low Cost) is basically the same card but without the costly optical isolation components and standard speed. The 1512C is the latest model added to the family and features two links (1024 channels). It can even read DMX data simultaneously.
All driver files are packed. Please use LHA.EXE to decompress files.
Download Card Operating System SLHDMX12.BIN
For cards 1512A and 1512B-LC, latest version.
Download Card Operating System SLHDMX16.BIN
For cards 1512B, latest version.
Download Card Operating System SLHDMX17.BIN
For cards 1512C, latest version.
Download Dynamic Link Library SLHDMX2.DLL
For 16-Bit Applications, latest DLL version.
Download Dynamic Link Library SLHDMX32.DLL
For 32-Bit Applications, first DLL version.
Download Dynamic Link Library SLHDMX33.DLL
For 32-Bit Applications, latest DLL version.
Download Drivers Collection 1512B
Operating manual 1512B
Why opto-isolated? A technical Note
Application examples for SLH DMX512 PC Interface Cards
Numerous industrial applications have been set up using SLH PC DMX512 interfaces. And eventually you may have been watching some TV shows without knowing the effects have been powered by our interfaces. Current production on german TV is the RTL show "Millionär gesucht" (there is a similar show on british ITV called "Who wants to be a millionaire?"
currently on TV
MORE INFO ON DMX EQUIPMENT:
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