Lall

Hi, Indeed, they work as you described. The ones I've seen so far had six pads, three on each sides (they were stereo jacks). When nothing is inserted, there's a piece of metal making the bridge between the two sides. When a plug is inserted, the piece of metal is bended and only touches one side. That side should be connected to the electronics and the other side should be grounded. Best regards, Lall

Héhé, je pense que tout le monde est passé par là ici, enfin je suppose. Pour ma part, j'avais lourdement sous-estimé la partie mécanique/cablage (c'est pas mon point fort faut dire), un peu l'alimentation et puis un peu l'aspect systeme complet. Ca a l'air simple comme de jouer aux légos mais c'est pas entierement vrai en fait. Enfin c'est pas très compliqué non plus. Tout dépend du niveau de fini et de perfectionisme que tu veux y mettre à vrai dire. Je sais pas, l'anglais ne me posant pas de problème je ne suis pas trop les traductions mais il me semble bien qu'un effort avait été fait pour traduire certaines pages. Je ne sais pas si le tuto fait partie de ces pages ou pas... A+ Lall

Hi Stryd, My 2cents on the question... From a pure C coding point of view, there's no problem in doing recursive functions. Things to watch out are: - that you, of course, need a way to break the circle and go out of your recursion - in the embedded world, that you must carefully check that the stack does not overflow with the return address, the parameters and maybe a register or a pointer (as done on the 68HCS08 for example) that would get pushed on the stack. You can easily get stack overflow so the best is to limit the number of recursions you have. I think a good way to start is to look at the C calling convention to see how it works exactly and to make sure that you do not risk a problem with the stack. Now all this nice text to end up saying that I've never tried that with SDCC on a PIC ;D so I don't know if that will be of much help... Best regards, Lall

On en discute effectivement :) Par contre, deux options sont possibles: - prendre un chip de chez Cypress qui ressemble le plus possible à l'actuel et avoir le meme genre de contraintes en terme de mémoire qu'actuellement mais par contre en réduisant normalement considérablement le temps de retravail software. - prendre un autre chip à choisir qui permette de faire plus, peut-etre d'etre plus facile a approvisioner, ... mais par contre au prix d'une ré-écriture quasi complete du soft. Les deux options sont alléchantes en fait, je pense qu'on va encore se tâter un peu avant de se décider :) A+ Lall

En fait, il faut quand meme bien prendre son temps pour lire un peu tous les schématiques et docs des différents modules (Core, DIN, DOUT, ...) ainsi que des interconnections entre modules (au niveau appli i.e. SID, SEQ, FM). Sans une compréhension minimale du systeme, c'est le coup à se planter... A+ Lall

Hi Moxi, Quite some time ago, I found the following about drifting parameters: http://www.musicdsp.org/archive.php?classid=1#183. I always wanted to try it on some audio effects but never did in the end :( It does not look too complex except for the random function but I believe a pseudo-random can be realized in a more or less efficient way if needed. Anyway, as the guy says that drifting code is being executed on a long term cycle so in the end the CPU consumption should be pretty low I suppose. Best regards, Lall

Salut ukn, Si tu te lances dans un Step C, il n'y a pas besoin de passer par le Step A ou B. C'est vraiment l'une ou l'autre. Certaines personnes (dont moi) préferent commencer par une Step A parce que c'est vraiment simple et que du coup tu peux très vite entendre le SID à l'oeuvre. Pour les kits, ca se trouve chez SmashTV (http://www.avishowtech.com/mbhp/) ou chez Mike (http://www.mikes-elektronikseite.de/midiseite.htm). A+ Lall

Hi, You can maybe check if the constrast voltage needed by your LCD should be negative or positive. I don't remember exactly what it does when you don't have the right one but if I remember correctly you don't see any character on the screen. Best regards, Lall

merci :) Je dois dire que je sais pas trop, on a commandé ça via Internet et principalement chez Farnell si je me souviens bien. Enfin tous les chips doivent être dispo ailleurs je pense à part l'EZ-USB qui arrive en fin de vie et qui va devenir difficile à trouver. Un fer à souder avec une panne fine et y avait aussi un autre fer plus gros avec une forme spéciale pour faire "de la soudure à la cuillère". En gros, tu mets le chip et de la pate a souder et tu passes la "cuillere" dessus et la soudure se met d'office au bon endroit car comme c'est un PCB fabriqué, il y a un masque de soudure qui fait que la soudure ne se met pas n'importe où et que tout le bazar se met comme il faut et ne fait pas de court-circuit. A+ Lall

Avec des potes on a réalisé un projet de multi-effet ADIYUPT (almost do it yourself using proper tools ;D) car il faut faire fabriquer les PCBs et certains composants sont difficiles à souder. C'est un copain qui baigne là -dedans toute la journée pour son boulot qui les as soudés d'ailleurs. Sinon, c'est entièrement controlable avec quatre potards mais aussi à partir du PC pour le reste des parametres qui ne sont pas assignés à un potard. C'est sur le site suivant à la rubrique Miss Parker: http://www.axoris.be/ A+ Lall

Actually, the (very valid) point about the backlight makes me rember about the following thread about LCD screen saver: http://www.midibox.org/forum/index.php?topic=7779.0 That would be a kind of inbetween compromise... :) Best regards, Lall

Hi Mess, Sourceforge is proposing SVN next to CVS but I don't know whether SVN is fast or not on SF, I've only used CVS so far... Best regards, Lall

Salut, A mon avis, ça va sonner un peu cracra comme montage. Y a jamais que 10 bits en entrée et 8 bits en sortie comme résolution donc ça va sonner comme les premieres soundblasters d'il y a 10-15 ans. Remarque que ça peut avoir son petit effet en un sens. Tu peux "simuler" la perte de qualité avec un éditeur audio qui te permet de sauver du .wav en 8 bits. Pour moi, il vaudrait mieux s'orienter vers d'autres solutions. Par exemple, le montage a déjà 2-3 ans donc j'imagine qu'il y a moyen de trouver de nouveaux micro-controlleurs avec plus de résolution côté AD et DA. Une autre solution est d'ajouter des convertisseurs AD/DA séparés avec plus de résolution mais là il faut s'assurer que le micro-contoleur peut s'interfacer avec. Sinon, le Wavefront AL3201 est assez sympathique dans son genre: http://www.wavefrontsemi.com/UserFiles/File/AL_Info/AL32/Wavefront%20AL3201BG%20Single%20Chip%20Reverb%20Data%20Sheet(1).pdf. Il s'agit d'un DSP qui a été désigné pour des effets audio type delay/reverb/... L'avantage de ce chip est qu'il contient 16 presets d'effets donc pas besoin de programmer le bazar (mais on ne peut pas controler les effets non plus malheureusement) et on peut aussi utiliser un programme utilisateur. Tu peux trouver le schématique de leur carte d'évaluation à l'adresse suivante: http://www.wavefrontsemi.com/UserFiles/File/AL_Info/AL32/WavefrontEV3201A.pdf Toute la partie micro-controleur est inutile tant que tu veux uniquement utiliser des presets ce qui simplifie pas mal la chose. Le point un peu embêtant est que ces chips ne sont dispo qu'en SMD mais ca reste facilement soudable. Bon maintenant il est clair que pour un débutant, ca serait plus abordable de ré-utiliser tel quel le montage que tu as trouvé et d'expérimenter un peu avec... A+ Lall

Hi LyleHaze, Indeed, you're right. From the lifetime point of view, LDO will help, very good point. I thought you were having power consumption in mind... Best regards, Lall

Hi all, If the input voltage remains unchanged then the Low Dropout will not bring any gain as the difference between its input voltage and output voltage will remain unchanged as well. In order to have a gain from a LDO, the input voltage must be reduced by the amount that the LDO makes you win compared to classic linear regulator. Another option is to use switching power supply. They have very good efficiency factor and as there's no audio in this box, noise they can generate is not that crucial. You have to watch out that it seems to be a complicated subject, you must use specialized chips to do lion battery recharging if you want it to work. Look at Linear Technology, Analog Devices or TI portfolio for this matter... One thing I've leared lately about these batteries is that they normally have (some don't) some integrating electronics preventing wrong use of the battery. Without this protection, the battery could litteraly burn and as I've been said, there's not really anything that can stop this fire... (sounds like a nice experiment too ;)) Best regards, Lall

Hi, I did burn a PIC and a LCD controller most probably as well with a defective PSU. It was a home-made one, never put into a box and the regulator moved enough to get off the PCB tracks and provide the input voltage at its output... We're currently redesigning our SEQs with Xanboroon and I'm adding some protections like fuses and zener and protection against reverse voltage to make sure that such a thing will not happen again. Actually, it's even more severe in the case of a SID or a FM where the chips are quite difficult to get. I think it's pretty good practice to try to add such protection, it's so easy to make mistakes... Best regards, Lall

Hi dj3nk, Yes and no: - yes Miss Parker is our work and - no because it's a friend who did the electronic design of the beast and - yes because I did most of the firmware part and the PC software and - no because another friend did the Linux stuff in the PC software ;D Best regards, Lall

Indeed the SID and its support will be really the limiting factor here. Compared to the height of SID+support, I believe using SMD capacitors won't be an issue even if electrolytic ones are used. For the rest, I'm pretty sure you can find everything you need in SMD package, there's nothing fancy used here. For the power consumption, I don't know if it would consume that much because you will only have a PIC, a SID and an optocoupler basically. I guess it's out of the question to scavange this poor iPod with buttons, leds and the usual stuff we use to connect to DIN and DOUT. So big consumers like LCD, Leds, ... are out and the power should go down. Even if the LCD of the iPod is used I suppose it's made for battery operation so should not consume too much. So in the end, there's maybe not really a problem of heat dissipation in the box but I also doubt it would run for long on battery. Anyway the idea is cool (even if maybe not doable), it would be soo sexy to have a SID in an iPod :D Note that it would be much easier from space utilization point of view with the Midibox FM as the synth/DAC chips are already SMD ;) Best regards, Lall

Héhé, excellent news :) The solution is indeed very logical... once it's found ;) Best regards, Lall

The SDCC doc talks about IEEE float support and to me IEEE float is signed by default but I may be wrong. I've actually never seen an unsigned float anywhere and on the bunch of platform I've used float is always signed float. But anyway I would say it's worth a try, it cost only very little time to do it and who knows about the oddities of a compiler or another ;) Best regards, Lall

Hi JD, Have you tried with the following? pitch = pitch * -1.0f; Note that the following that you tried should work too: pitch = pitch - pitch - pitch; Stupid question but have you included the float library? I guess so otherwise you should have errors/warnings of undefined stuff. And is the memory model of the library matching the memory model of your program? I don't remember if it's applicable in this context of SDCC, I used it too long ago... Maybe you can look at what the compiler is generating in terms of assembly code from your code to check how this code is interpreted. Best regards, Lall

I'm in Belgium. We've gone in one night from winter time to spring time, strange weather... I'll check about the shipping cost to Canada to see if it's worth it or not. Best regards, Lall

Maybe you could use something of that kind: http://www.vk2zay.net/article.php/31 ? Apparently it uses Linux which could be a bit annoying but I suppose it should run using a Knoppix for example if you don't have a Linux installed. Otherwise most probably, I should be able to burn one for you by hacking a bit my Miss Parker. Where are you located? Maybe something stupid but have you tried connecting it directly to the PC or through a USB hub? I have a USB soundcard at home that does not work through a hub and absolutely requires a direct connection to the PC. I doubt that the EZ-USB has such requirements but ok... A last one, are you trying the EZ-USB without an eeprom connected to make 100% sure that a firmware does not get loaded by accident? If I remember correctly, it's enough that the first value of the eeprom is the magic number for the rest to be considered as valid firmware. The fact that the device is seen correctly in OSX tends to prove that it's not the cause of the problem though. Best regards, Lall

The Miss Parker at: http://www.axoris.be/index.php

I think you're right, that bug should not affect the way Windows recognizes the device. It should only affect the MIDI data you would send out using the UART. The strange thing is that Windows recognizes your device and gives its name from the descriptors so the transmission must happen in a way or another but at the same time something must be missing or must be wrongly interpreted to allow Windows to know that it's a MIDI interface and not only a generic USB audio thing. That's smelling the hours of debug I fear... Best regards, Lall