More actions
No edit summary |
No edit summary |
||
| Line 14: | Line 14: | ||
Since version 1.1 of the Ekdahl FAR Firmware, all commands are grouped in a hierarchical fashion according to their ''modules'' and each ladder in the hierarchy is separated by a period ("."), this works very much like folders or directories in a regular computer. Every ''module'' can contain both ''commands'' and other ''modules''. For instance, everything associated with the ''bowing wheel'' is now collected under "bowingwheel" ''module''. That in turn contains a "dcmotor" ''module'' which handles direct control of the bowing motor. It also has a "pid" ''module'' that handles bow frequency among other thing. | Since version 1.1 of the Ekdahl FAR Firmware, all commands are grouped in a hierarchical fashion according to their ''modules'' and each ladder in the hierarchy is separated by a period ("."), this works very much like folders or directories in a regular computer. Every ''module'' can contain both ''commands'' and other ''modules''. For instance, everything associated with the ''bowing wheel'' is now collected under "bowingwheel" ''module''. That in turn contains a "dcmotor" ''module'' which handles direct control of the bowing motor. It also has a "pid" ''module'' that handles bow frequency among other thing. | ||
If for instance we would like to start the ''bowing wheel'' and set its frequency to 82.5 Hertz we could send the Ekdahl FAR the following ''command string''<pre>FAR < 1.1: | If for instance we would like to start the ''bowing wheel'' and set its frequency to 82.5 Hertz we could send the Ekdahl FAR the following ''command string''<pre>FAR < 1.1: | ||
| Line 175: | Line 173: | ||
</pre>This may return something like<pre> | </pre>This may return something like<pre> | ||
FAR < 1.1: | FAR < 1.1: | ||
[irq]mev:pb:" | [irq]mev:pb:"bowcontrolharmonicshift:pitch*4" | ||
FAR 1.1: | FAR 1.1: | ||
[irq]bw[0].mcf[0].mc[0].pb:"bowingwheel.harmonicserieshandler.harmonicseries.shift:pitch*4" | [irq]bw[0].mcf[0].mc[0].pb:"bowingwheel.harmonicserieshandler.harmonicseries.shift:pitch*4" | ||
</pre>The first part of the return message tells us that the incoming message is of "rqi"-type ("[irq]") which means it's responding to a information request ''command'' sent. The second part tells us what ''command'' the | </pre>The first part of the return message tells us that the incoming message is of "rqi"-type ("[irq]") which means it's responding to a information request ''command'' sent. The second part tells us what ''command'' the information request return is responding to and any ''parameters'' that may be pertinent. The third part of the message is the actual data stored. | ||
For the FAR < 1.1 the data returned is for the ''command'' "mev" with the first ''parameter'' set to "pb", the ''command reference'' tells us this means the ''command'' "midieventhandler" and the ''parameter'' "pb" indicates this has to do with the ''pitch bend''. The data is " | For the FAR < 1.1 the data returned is for the ''command'' "mev" with the first ''parameter'' set to "pb", the ''command reference'' tells us this means the ''command'' "midieventhandler" and the ''parameter'' "pb" indicates this has to do with the ''pitch bend''. The data is "bowcontrolharmonicshift*4". | ||
For the FAR 1.1 the data returned is for the ''command'' "bw[0].mcf[0].mc[0].pb" (bowinwheel[0].midiconfigurationhandler[0].midiconfiguration[0].pitchbend) and the data is "bowingwheel.harmonicserieshandler.harmonicseries.shift:pitch*4". Note here that if we have several different ''MIDI configurations'' stored and we're currently using configuration number 2, the returned message would have been "bw[0].mcf[0].mc[2].pb". | For the FAR 1.1 the data returned is for the ''command'' "bw[0].mcf[0].mc[0].pb" (bowinwheel[0].midiconfigurationhandler[0].midiconfiguration[0].pitchbend) and the data is "bowingwheel.harmonicserieshandler.harmonicseries.shift:pitch*4". Note here that if we have several different ''MIDI configurations'' stored and we're currently using configuration number 2, the returned message would have been "bw[0].mcf[0].mc[2].pb". | ||
that the ''pitch bend MIDI message'' is executing a " | that the ''pitch bend MIDI message'' is executing a "bowcontrolharmonicshift" / "harmonicseries.shift"-command with the parameter ''pitch*4''. Looking in the ''command reference'' we can see that ''"''bowcontrolharmonicshift" / "harmonicseries.shift"-''command'' shifts the frequency of the ''bowing wheel'' from the currently selected harmonic. The first (and only) ''parameter'' sets how much we want to shift it (the range depends on the "bowcontrolharmonicshiftrange''"'' / "harmonicseries.shiftrange"-''command''). | ||
If we look in the list of ''[[The Ekdahl FAR - Command langue#Variables|variables]]'' above we can see that the ''pitch bend MIDI message'' will set the '' | If we look in the list of ''[[The Ekdahl FAR - Command langue#Variables|variables]]'' above we can see that the ''pitch bend MIDI message'' will set the "pitch"''-variable'' which is indeed used. Now what is the '''*4''<nowiki/>' all about? Well the "bowcontrolharmonicshift" / "harmoniceseries.shift"-''command'' expects a ''16-bit signed'' value as its ''parameter''. This means that the valid ''parameter'' number can be anything from -32767 to 32767. A full ''harmonic shift'' downwards according to the range set is equal to -32767, a full ''harmonic shift'' upwards is 32767 and no ''harmonic shift'' is 0. The ''pitch bend MIDI message'' however is only 14-bits, meaning its range is -8192 to 8192. So we have to multiply ''pitch'' by 4 in order to meet the requirements of a ''16-bit signed parameter''. | ||
This whole thing about number of bits can seem confusing but in the end it's all about how fine control you have over things; the more possible values, the more detailed control. In fact, most ''MIDI'' values are only 7-bit (!) meaning a range of 0 - 127. While this may sound like a lot of detail for something like a volume control, it is not even close to enough resolution to for instance set the ''bowing | This whole thing about number of bits can seem confusing but in the end it's all about how fine control you have over things; the more possible values, the more detailed control. In fact, most ''MIDI'' values are only 7-bit (!) meaning a range of 0 - 127. While this may sound like a lot of detail for something like a volume control, it is not even close to enough resolution to for instance set the ''bowing frequency''. Even if you would limit yourself to a single octave the instrument would never be able to be properly in tune. The idea of limiting the Ekdahl FAR to what is possible through ''MIDI'' seemed like a poor choice thus it was decided that <u>most</u> parameters will instead be 16-bit. | ||
Now lets look at a more complex example, the <u>default</u> ''Note On MIDI message''. On a stock Ekdahl FAR, executing<pre> | Now lets look at a more complex example, the <u>default</u> ''Note On MIDI message''. On a stock Ekdahl FAR, executing<pre> | ||
FAR < 1.1: | |||
rqi:mev:noteon | rqi:mev:noteon | ||
</pre>Will return something like<pre>[irq]mev:noteon:' | |||
FAR 1.1: | |||
rqi:mcf.mf.non | |||
</pre>Will return something like<pre>FAR < 1.1: | |||
[irq]mev:noteon:'bchb:note,bmr:1,bpid:1,bpe:1,se:(velocity*512)*(1-notecount),bcsm:0' | |||
FAR 1.1: | |||
[irq]mcf[0].mc[0].non:'bw.hsh.hb:note,bw.dcm.ru:1,bw.pe:1,bw.bp.en:1,so.en:(velocity*512)*(1-notecount),bw.sm:0'</pre>As can be seen, there's a lot of stuff going on here! First of all, notice that everything after "mev:noteon:" / "mcf[0].mc[0].non:" is situated in between single quotes (') - this is <u>absolutely crucial</u> for the Ekdahl FAR in order to know that everything within those last two quotes is part of the last ''parameter'' of the "mev" / "mcf.mc.non"-''command''. | |||
Now let's break down what happens when this ''MIDI message'' is received, i.e. when a ''MIDI'' key is pressed down: | Now let's break down what happens when this ''MIDI message'' is received, i.e. when a ''MIDI'' key is pressed down: | ||
# | # "bchb:note" / "bw.hsh.hb:note" - Invokes the "bowcontrolharmonicbase" / "harmonicserieshandler.harmonicbase"''-command'' with the first ''parameter'' set to the ''variable note''. This sets the ''base harmonic'' that the Ekdahl FARs ''bowing motor'' should be set to. | ||
# "bmr:1" / "bw.dcm.ru" - Sets the "bowmotorrun" / "dcmotor.run"-command to '1', starting the ''bow motor'' | |||
# "bpid:1" / "bw.pe:1" - Sets the "bowpid" / "bowingwheel.pidenable"-''command'' to '1'. Basically this enables the function that makes the Ekdahl FAR able to keep a stable frequency on the ''bowing motor''. | |||
# | # "bpe:1" / "bw.bp.en" - Sets the "bowpressureengage" / "bowpressure.engage"-''command'' to '1' which moves the ''bowing jack'' to the ''engage position'' | ||
# | # "se:(velocity*512)*(1-notecount)" / "so.en:(velocity*512)*(1-notecount)" - Executes the "solenoidengage" / "solenoid.engage"-''command'' with the value ''(velocity*512)*(1-notecount)''. This will make the ''solenoid'' strike the ''hammer'' with a force that is dependent on the ''velocity'' variable sent by the ''Note On MIDI message'' in order to make the ''hammer'' velocity sensitive. But it also adds the somewhat perplexing part "*(1-notecount)". "notecount" is a global ''variable'' that contains the number of MIDI keys that are currently being held down. If "notecount" is anything above zero, the outcome of the equation will either be zero or a negative number. The "solenoidengage" / "solenoid.engage"-''command'' requires a ''16-bit unsigned'' value, aka the only valid numbers are 0 - 65535. Anything below 0 will be interpreted as zero, so what this equation does is that it only fires off the ''hammer'' if there are no previous keys being held down - it's going into ''staccato'' mode. | ||
# | # "bcsm:0" / "bowingwheel.speedmode" - Sets the "bowcontrolspeedmode" / "bowingwheel.speedmode" to '1' which enables automatic shut down of the ''bowing motor'' after a given timeout. | ||
# | |||
The first two ''commands'' are the ''module''- and ''bow-''command. These ''commands'' are is intended for future versions of the Ekdahl FAR that may contain more than one string or more than one bow per string. For now ''0'' is the only valid ''parameter'' value that will be accepted for either ''command''.''<nowiki/>'' | The first two ''commands'' are the ''module''- and ''bow-''command. These ''commands'' are is intended for future versions of the Ekdahl FAR that may contain more than one string or more than one bow per string. For now ''0'' is the only valid ''parameter'' value that will be accepted for either ''command''.''<nowiki/>'' | ||