midiboxdmx
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midiboxdmx [2008/12/08 08:45] philetaylor |
midiboxdmx [2013/09/25 12:29] (current) smashtv forum link updated |
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| - | ====== MidiboxDMX ====== | + | ====== Intro ====== |
| + | Midibox DMX is a DMX512 compliant controller for Midibox created by Phil Taylor - phil@taylor.org.uk | ||
| - | A DMX512 compliant controller for Midibox created by Phil Taylor - phil@taylor.org.uk | + | Originally Discussed [[http://midibox.org/forums/topic/11597-dmx512-controller/|here]] |
| - | Originally Discussed [[http://www.midibox.org/forum/index.php?topic=12433.0|here]] | + | Here is a picture of my test system, It is enclosed in an old Strand Tempus 2-12 case (I bought 4 very cheap!). |
| - | Here is a picture of my test system, I will box this once I decide on an enclosure. I have also included a closeup of the only bit of extra hardware (other than MBHP modules) that is required! | + | {{:midiboxdmx:mbdmx-boxed.jpg|}} |
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| - | {{http://www.lansystems.co.uk/images/dmx/midibox-dmx1.jpg}}{{http://www.lansystems.co.uk/images/dmx/dmx-if.jpg}} | + | |
| ===== Concept ===== | ===== Concept ===== | ||
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| I have decided that after struggling with the limited memory of the PIC16F88, 352 DMX channels was just too ambitious. I have now reduced it to 256 channels. One of the main reasons for this decision is that I was missing too much IIC data and causing too many retries. I have now made the IIC handing interrupt based and buffered which seems to make it much more stable (I will be posting this update once I have tested it thoroughly.) | I have decided that after struggling with the limited memory of the PIC16F88, 352 DMX channels was just too ambitious. I have now reduced it to 256 channels. One of the main reasons for this decision is that I was missing too much IIC data and causing too many retries. I have now made the IIC handing interrupt based and buffered which seems to make it much more stable (I will be posting this update once I have tested it thoroughly.) | ||
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| + | ===== ANSI E1.20-2006 RDM Support ===== | ||
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| + | I have done some of the groundwork to providing RDM support, I have a copy of the ANSI E1.20-2006 standards document and the example C source from Wybron which give full details for creating an RDM responder. | ||
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| + | I have also been assigned a Manufacturer ID from ESTA. The reason that manufacturer ID's are important is that much like Ethernet, every RDM device must have a UID which is unique. The manufacturer ID that I have been assigned is 4D42h As it needs a 'company' name, it is assigned to my company (LAN Systems) as follows: "LAN Systems -- midibox project". Before anybody asks, this DOES NOT imply any commercial or other relationship between LAN Systems and the midibox project (there is none), they simply needed a company name to register it to. | ||
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| + | ESTA were concerned about controlling the allocation of UID's and I have committed to creating a website where people can request allocations, I will create this soon but as RDM support is quite a long way away I don't thinkt there is much of a rush! | ||
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| ===== Hardware ===== | ===== Hardware ===== | ||
| - | Pretty much all of the hardware is based around standard MBHP modules, the only addition is my simple TTL Serial <-> RS485 interface the schematic of which is below. I made it on a 6x6 piece of strip (vero) board (I didn't bother with header connectors): | + | Pretty much all of the hardware is based around standard MBHP modules, the only addition is my simple TTL Serial <-> RS485 interface the schematic of which is below. I made it on a 6x6 piece of strip (vero) board (I didn't bother with header connectors) |
| - | {{http://www.lansystems.co.uk/images/dmx/IIC-DMX_IF.png}} | + | After reading the RDM spec, I realise that a simple BIAS circuit will also be required, this is only 2 extra resistors (+ 120ohm terminator) so I will post a modified circuit soon. |
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| + | {{:midiboxdmx:iic-dmx_if.png|}} | ||
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| + | {{:midiboxdmx:dmx-if.jpg|}} | ||
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| Pretty much everything at the moment, | Pretty much everything at the moment, | ||
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midiboxdmx.1228725955.txt.gz · Last modified: 2008/12/08 08:45 by philetaylor
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