silicium

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About silicium

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    MIDIbox Newbie
  • Birthday 01/01/1970

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  1. usb

    Now almost 16 years later, there are enough videos on Youtube showing how to handle SMD. The problem is not only the low price of ready-made USB MIDI interface, but the need of open source firmware to study when you want to develop on the same microcontroller core, to build your OWN hardware with several ports and other I/O like digital audio, buttons, knobs, faders, displays, lasers, blinkenlights... The bigger AN2131QC had a parallel bus interface, if one wants to add two more MIDI ports with a dual UART like the TL16C752C, and can even run from external Flash (3.3V, and this requires the knowledge to make a bootloader to program it), but it looks too obsolete and hard to find cheap as new old stock, so if one likes coding in 8051 assembler and does not feel like switching to 32-bit ARM, it seems better to try its USB2.0 successor, the FX2LP CY7C68013A-128AXC.
  2. New Midi motherboard for Fatar SL 880

    I have this keyboard too, it still works but I started thinking about maintenance. I can write 8052 asm code easily. Some microcontrollers may be powerful enough. There are fast ones from Silabs (C8051F...) , Microchip/Atmel (AT89LP...) Maxim/Dallas (DS89C430). Then how to calculate key velocity with two contacts ? It seems too expensive to wire each contact to a pin with capture timer, as it would need a lot of slaves scanned by a master that sends MIDI messages. What is the way to do it in software (with external memory if needed, thatcan be accessed without stretched bus cycle), scanning the whole 88 keys each millisecond ?
  3. MIDIBox SEQ Lite V4

    How does SEQ compare to Quasimidi Cyber6? In need of a sequencer and a second master keyboard, I was tempted to buy one, then gave up after seeing it has an obsolete user interface with small screen and too few buttons to edit many parameters.
  4. Vends coffret console 19"

    A récupérer gratuitement + frais de port (13€), pour le coffret et les composants pouvant servir à un projet MB: ancienne console de commande d'éclairage en 0-10V, semble encore en état de marche après un test rapide (je pensais faire un convertisseur DMX/0-10V pour le module de puissance, mais comme j'utilise plus du MIDI je vais peut-être plutôt prendre une solution à base de MB + AOUT modifié avec des MAX528 à 8 bits seulement). http://i245.photobucket.com/albums/gg79/Ne3s23p2/ebay/DSC00049.jpg http://i245.photobucket.com/albums/gg79/Ne3s23p2/ebay/DSC00050.jpg http://i245.photobucket.com/albums/gg79/Ne3s23p2/ebay/DSC00051.jpg http://i245.photobucket.com/albums/gg79/Ne3s23p2/ebay/DSC00052.jpg
  5. [S] 19" black console enclosure

    For recycling or reuse, a console enclosure from a pre-DMX lighting controller, in black aluminum. Comes with color knobs, circuits for 0-10V faders, sequencer, power supply... many parts that could be reused with only a new PCB under the faceplate, or even just add a CV to MIDI converter inside ! Most parts seemed to be working. Get it for almost free except postage from France. http://i245.photobucket.com/albums/gg79/Ne3s23p2/ebay/DSC00049.jpg http://i245.photobucket.com/albums/gg79/Ne3s23p2/ebay/DSC00050.jpg http://i245.photobucket.com/albums/gg79/Ne3s23p2/ebay/DSC00051.jpg http://i245.photobucket.com/albums/gg79/Ne3s23p2/ebay/DSC00052.jpg
  6. MIDI to RS232 interface with LTC interface?

    There was a MIDI <-> RS-232 converter in issue 04/2001 of Elektor magazine. It gets MIDI bytes at 31250 b/s and forwards them to serial port at 38400 b/s. The other way it stores serial port data coming at 38400 in a FIFO and forwards ASAP to MIDI at 31250. The Windows driver is from Yamaha at http://www.global.yamaha.com/download/cbx_midi/index.html. Instead of software UART like in MidiMerge with PIC, it used a DS80C320 microcontroller (8051 family) that has a second hardware UART and a 128 bytes FIFO, running at 24 MHz for MIDI baud rate and using 1.8432MHz crystal oscillator for PC baud rate. That was an old design with external RAM and EPROM. Most of today's microcontrollers have on-chip Flash and SRAM. I redesigned it with a DS89C430 with 1Kbyte FIFO, running at 32 MHz, and using second osc at 3.6864MHz. Thanks Maxim/Dallas for the free sample. It has a builtin bootloader and can be programmed onboard with their MTK utility and HEX file from assembler. For PIC haters like me (I learned 8052 quite fast but vomited after reading PIC datasheets and mnemonics :P), the DS89C430 is fast enough to implement some MIDI filters or generators, using port I/O (23 free port pins) or memory-mapped up to 63K address space. If somebody is interested in such alternative MB hacks or just the basic MIDI<->RS232 baud rate converter, I can share modified schematic and source code.
  7. BMOW

    Back to topic, a full MB system is maybe not a BMOW but still a Middle Mess of Wires. When everything is connnected, are not there too many entangled ribbon cables ? I would not want to build one set of core and modules with their current layout. Remember, most failures come from bad connectors. Depending on project's case, why not draw all boards with a common power & I/O channels layout, to allow 2D flat chaining, 3D vertical stacking like PC/104 systems, or even keep all the boards panelized in a single large one ? There is fee PCB software that is enough for two-layer boards and without the limitations of Eagle.
  8. MIDI merge

    Sorry for late reply. I can test your hex file built with your toolchain as I have finished a second MM board and the programmer is still on. BTW I tried an HCPL2530 dual optocoupler instead of two 6N138's. It works with at least 2.7k pullup resistors.
  9. MIDI merge

    I finished and test my first MM board :) The downloaded firmware did not work with a PIC16F877A (programmed with an universal programmer, not a cheap hack). It was successful after editing midibox.h to add 'A' there: #ifdef __16F877A  #include <p16f877A.inc> and rebuilding with MPLab IDE. The PCB layout has some mods: -7805 laid down on copper side with tab contact to ground -4 SMD leds and their resistors between PIC pins
  10. Are the state machines for midi merge described somewhere at midi message level ? I would like a better midi merge box with COM I/O to PC (to have two merged MIDI inputs and one output on any PC, using compatible baud rate of 38400, with at least one COM port but without using USB). I plan to use a double UART like SCC2692 and external RAM or asynchronous FIFO chips, at least twice larger than PIC18 internal RAM, and have not chosen the target microcontroller yet (PIC or 8052). How are working the ringbuffers of MM ? I don't need to filter content, not interested in the MidiRouter design.
  11. MIDI merge

    Another idea to modify a MIDI merge with to_com I/O: add a MIDI output. Two I/O's, one at 38400, the other at 31250 bps. This would make a serial port to midi interface, also called baud rate converter, for those who can't or don't want to add USB/PCI/whatever MIDI interface, but have spare serial port. There is a serial MIDI interface driver for Linux in Ubuntu-Studio: see alsa.opensrc.org/index.php/Serial Is there enough memory and processing power left in a PIC to add a software serializer and some flow control to the existing merge and software deserializer ? Out of MIDIBox, there is another solution which I will evaluate too: the 8051-based serial interface from maxmidi.com . It will cost less for me (except for a bigger PCB) because I have recycled several 8031 + EPROMS 8) Update: this interface design from yesteryears is a piece of crap, dead with only Win3.1/95 driver :P, there is no PCB, cheap power supply drawn from RS-232 lines, transistors and opamps instead of a true line driver/receiver like MAX235, complex 8031 code (software uart), hard to hack without source code... maybe well for mass production with low power x51 mpu, if able to be sold under $30, but not for DIY kits where part of the fun is in hacking, not buying programmed components.  I will redesign it with a second external uart.
  12. Giving for free + shipping cost (from France) a Packard-Bell soundcard for 16-bit ISA, was tested some years ago. Here are the interesting SMD parts onboard waiting for a MBFM project: one YMF262-M one YAC512-M four TL074C decoupling caps 14.318 MHz crystal, not SMD but HC49U package (it is easy to build an oscillator, just Google for schematics using a CD4069UB inverter gate biased at VDD/2 with a resistor between input and output, make sure you're using an unbuffered version UB suffix, and use the remaining gates for buffering your oscillator's output) other parts: one GD4053B SMD (cmos analog mux) one 7805 voltage regulator TO-220 package, with screw & nut (no soldered tab) one X24C00P EEPROM one 12 MHz crystal, HC49U package two short crystals, HC49US or similar (R245KD55, R169PD335) one Crystal CS4231A soundchip two Packard-Bell asics, probably for DMA and old CD-Rom control (has three sockets for Sony, Mitsumi, Panasonic drives from the days before IDE/ATAPI) three stereo jacks The card (found in a PC on the sidewalk) came with a Korg daughterboard that I will put in a box as a standalone GM expander 8). There is also a 558 quad timer (4x 555) in diL package that I am likely to recycle unless one really wants a complete card for gaming  :P
  13. PC case mod: MIDI sockets (like good old Atari)

    A thought about safety, for hackers who don't power off before opening case, how is protected the +5V line on Asus MB's MIDI connectors ? Unless the front 5.25" bay interface is enclosed in a plastic case, there is always a risk that a soldered pin could touch the ground from chassis or a CD/DVD drive below. If someone has a spare motherboard, thanks for looking whether it's a fuse or a resistor and locating it, probably in SMD package. Another suggestion, for recycling old ISA MIDI interfaces like the WinMan 2x2, useless on PCI(-express)-only motherboards: some MIDIBox-based controllers for a VSTI softsynth and VST host that can boot w98 & run from CompactFlash without display, on a PC-104 system with ISA connector, all in the same case as the MIDIBox... I don't know yet which softsynth to choose (probably not a CPU-eating monster). Any ideas ?
  14. Hi MIDI & PIC hackers, I found midibox a few days ago and it gives me nightmares because I don't have time to start such exciting projects now. I like the ability to use COM ports as inputs for controllers. Now, before dreaming again, here is my first MIDI hack: a PC case (Antec P160, all-aluminum, blue LEDs on frontal fan intake) has just been modded with two MIDI sockets on an unused 5.25 front bay. I thought that buying an external MIDI cable sux, the extra joystick plug is a waste (me never gaming, a joystick would only be useful around a MIDIBox core), and small breakout boxes hanging around a nice tower case sux too. As expected, the motherboard UART MIDI OUT pin has not enough fan-out to drive an optocoupler's internal LED (hardware synth MIDI IN for example),then I added some TTL gates for buffering (NAND wired as two inverters). The MIDI IN uses a 4N35 optocoupler and 1K pullup resistor without additional buffering. I did not check the waveforums with oscilloscope nor test long SysEx dumps, but playing a bit on a MIDI keyboard did not seem to show missing Note On/Off messages in MIDI-Ox monitor. Here are the schematic, PCB in Eagle format. I added a 7400 NAND SMD package instead of my prototype with a DIL package hanging below the PCB with bare wire. The PCB has been optimized for homemade photo etching: larger traces, pads, vias, smaller drill holes. Happy case modding ! :o AsusMB-MIDI.zip AsusMB-MIDI.zip