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<TITLE>RE: My Midi controlled VCF module</TITLE>
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<P><FONT SIZE=2>> -----Original Message-----</FONT>
<BR><FONT SIZE=2>> From: Ullrich Peter [<A HREF="mailto:Ullrich@kapsch.net">mailto:Ullrich@kapsch.net</A>]</FONT>
<BR><FONT SIZE=2>> Sent: Wednesday, August 02, 2000 4:31 PM</FONT>
<BR><FONT SIZE=2>> To: 'Jeroen Proveniers'</FONT>
<BR><FONT SIZE=2>> Subject: AW: My Midi controlled VCF module</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Hallo! </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> >Yes, but the AT89S8252 is twice as expensive! I'm also </FONT>
<BR><FONT SIZE=2>> considering an AVR AT90S4414, which costs the same as the </FONT>
<BR><FONT SIZE=2>> AT89C52, but </FONT>
<BR><FONT SIZE=2>> >has 256 bytes of E2PROM, and is much much faster (almost 1 </FONT>
<BR><FONT SIZE=2>> million instructions per MHz; that's 12 times faster than an 8031).</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Be careful - I have heard that the AVR series need an </FONT>
<BR><FONT SIZE=2>> external reset circuit as the are not brownout save!!!</FONT>
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<P><FONT SIZE=2>A resistor and capacitor will suffice I think. Otherwise, a MAX690 (unfortunatly expensive) will do the job nicely.</FONT>
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<P><FONT SIZE=2>> >The only problem is that I have to program in assembly, but </FONT>
<BR><FONT SIZE=2>> the benefits can justify this easily. I can increase the </FONT>
<BR><FONT SIZE=2>> sampling frequency to >1KHz for example, which is now a bare 100Hz.</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> I think for this purpose assembly routines are only necessary </FONT>
<BR><FONT SIZE=2>> for the LFO-highspeed parts i.e. interrupt routienes - am I right?</FONT>
<BR><FONT SIZE=2>> The standard midi routines can be C or PLM or pascal as </FONT>
<BR><FONT SIZE=2>> interfacing to assembler can be done quite nice.</FONT>
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<P><FONT SIZE=2>Yep, but I do only have the free AVR Studio... no C compiler, so I will have to write everything in assembly. Not really a problem, I've done that for many years.</FONT></P>
<P><FONT SIZE=2>And because I've something working in C, it not diffucult to translate it into asm. Maybe I can add another 10 LFO's -:)</FONT></P>
<P><FONT SIZE=2>> >I have a programmer that can handle both, so I will give </FONT>
<BR><FONT SIZE=2>> both chips a try. </FONT>
<BR><FONT SIZE=2>> I see. But if you are interested that other can also build </FONT>
<BR><FONT SIZE=2>> the system the parallelport version would be nice.</FONT>
<BR><FONT SIZE=2>> If you don't want to publish it - no problem as you can program it.</FONT>
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<P><FONT SIZE=2>I'll sell pre-programmed chips</FONT>
<BR><FONT SIZE=2> </FONT>
<BR><FONT SIZE=2>> >> Which programming language will you use? PLM, C, PASCAL, </FONT>
<BR><FONT SIZE=2>> ASSEMBLER? </FONT>
<BR><FONT SIZE=2>> >I've made my prelimiary code in C, Keil C to be exact. </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Which version? I have 5.2. And I also got the franklin </FONT>
<BR><FONT SIZE=2>> windows version...</FONT>
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<P><FONT SIZE=2>Keil C v5.2 and uVision v1.32. Licensed, at my work. At home I've some demo version that works equally well. It should stop at 2Kb code, but it doesn't.</FONT></P>
<P><FONT SIZE=2>JJ</FONT>
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