MIDIbox SEQ V4 - Construction Photo Tutorial

[Hawkeye]

Hola,

after getting infected with the MB spirit, it is time for another realtime photo-documented feed of a new project, this time a custom MIDIbox SEQ V4 :-).

http://discourse.midibox.org/t/topic/14451

This MB SEQ variant will include a lot of custom tinkering and therefore has much more room for mistakes and utter failure. If this happens, I expect compassion and tears from you, fellow MBers ^^.

What to expect? We will build a MB SEQ Core in-a-box (retrofitted to a Commodore 1541-II case), a breakout-box Control Surface in a slim, thin and wide aluminium box which can be mounted directly below your master keyboard to minimize hand movements when switching between sequencer and keyboard action. Aiming for VFDs, an integrated AOUT-NG module for Control-Voltage output, duo-color flat-head rectangular step LEDs, a drilled LED matrix bpm indicator, nice Wilba-CS-style keycaps and switches, push-accelerated step encoders and an external BLM. Every step will be photo-documented. I will provide a full parts list and links to parts sellers, where possible.

People interested in building a SEQ from this tutorial may need to adapt a few things… they may not want to use the VFDs or the commodore floppy case for the base unit, but these parts can be substituted. For anyone interested in building a SEQV4 more quickly, I would totally recommend using Wilbas PCB - it is straightforward and saves time and money. In other words: only use this approach if you have space constraints and like the idea of a slim breakout-box CS or wish for a personal customized control surface layout.

Thanks to everyone who made this possible, of course especially TK. and Wilba, who have done a terrific job in realizing wishes, adding requested features to the MBSeq-Software within a week, sending out tech documentation within less than an hour and answering dumb questions… the support here is more awesome than Chuck Norris doing push-ups :-). Also thanks to SmashTV for providing parts in fantastic quality and Seppoman for the AOUT_NG module. Ah, and not to forget nILS … :-).

As usual, I am interested in your comments on the way - note though, that they might get deleted afterwards, if this project turns out to be working in the end :-).

Lets go and have fun!

Hawkeye

[Hawkeye]

Step 1: Prepare the Case for the Sequencer Core and Modules

Parts used:

Commodore 1541-II floppy drive (available from ebay)

Phillips screwdriver

Cutter knife

Your favorite desoldering equipment

Description:

* Every good journey should begin with massacre :-). Grab a malfunctioning 1541 disk drive in good physical shape (photo 1).

* Disassemble (photos 2 to 4)

* Use the cutter knife to cut away any inner plastic spacers used to hold the 1541 mainboard (photo 4).

* Grab the 1541 PCB and desolder the right serial port and the power switch.

* Do not throw away the 1541 PCB yet, we will need it it the next step.

* Have a cool beverage and enjoy the carnage :-).

[Hawkeye]

Step 2: Prepare the Power Supply Unit

Parts used:

* 5V/+12V/-12V open frame PSU (should have 2A on the +5V chain) (Reichelt PSA 25L-301)

* PSU plug kit (Reichelt PSA 60-STECKER)

* A sufficiently sized plastic or aluminum case (Reichelt TEKO WALL 2 or bigger)

* A rubber connector (german: Kaltgerätestecker Reichelt KES 1)

* 10 pcs M3 12mm screws (any mechanical store or Reichelt)

* 10 pcs M3 nut (any mechanical store or Reichelt)

* 4 pcs M3 nylon washer (any mechanical store or Mouser)

* Commodore 1541 PCB from step 1

* Commodore 1541 serial/data cable

* A bench drill or a hand drill with a 2mm and a 3mm drill

* A few centimeters of cable

* Electric isolation tape

* A 3mm LED and a 220 ohm resistor

* A drop of superglue

* A dremel tool with a cutting wheel

* Your favorite soldering equipment

Description:

We need proper power for the VFDs, and we also want to use the AOUT_NG module, which needs a bipolar power supply (-12V/0V/-12V), that´s why we use an open frame PSU kit commercially available.

* Trim the PSU case, so that the rubber connector and the open frame PSU fit (photo 1).

* Cut a piece of the 1541 PCB (photo 2) containing the left serial port connector, so that it fits neatly into the case (photo 3). Don´t forget to cut the surface connections with your dremel tool (photo 4).

* Solder six power connection wires to the backside of the piece of the 1541 PCB (photo 5). Don´t mind the alignment, we will measure the voltages later on.

* Drill the piece of the 1541 PCB and the bottom of the case. Fasten the serial port connector PCB with M3 screws and nuts (photo 6). Mark the area, where we will plug the serial cable (used as power cable) and cut it, so that you can plug in the cable.

* Install the open frame PSU using the same method (drill the floor of the case and insert M3 screws, use nylon washers as spacers and fasten with M3 nuts (photo 7).

* Crimp and solder the AC mains connector cable and connect to the PSU. Fasten the rubber connector using M3 screws and nuts (photo 8).

* Create the power connector by crimping the six power connection cables. Add a small cable for the power LED to a +5V and a GND line ( note: if you measure using your multimeter with power on, take security precautions, as there is dangerous voltage nearby ).

* Solder a 220 ohms resistor and a 3mm LED to the end of the cable and isolate with electric tape (photo 9).

* You should drill the case for better air ventilation. You can use graph paper and a 2mm and a 3mm drill (photo 10) to create a matrix of holes. Also create a 3mm hole for the power LED.

* Fasten the LED using a drop of superglue.

* Enjoy your new PSU, it should look like photo 11. All voltages should be available on the serial connector cable, which we will use to power the Core32.

[Hawkeye]

Step 3: Core32 - Solder Diodes and Resistors

Parts used:

Core32 Module PCB with IC (AVI Showtech - SmashTVs shop)

Core32 Parts Kit (AVI Showtech - SmashTVs shop)

Adhesive tape (e.g. tesa tape) for “tacking” components

Your favourite soldering equipment

A multimeter to measure resistor values

Description:

* Before starting, note that there is another step-by-step tutorial on finishing the Core32 available on ucapps.de and there is a nice interactive PCB map on SmashTVs site here.

* Credit, where credit is due. SmashTV does a magnificent job in providing PCBs with the presoldered STM32 core and also delivers a complete parts kit (photo 1).

* Following the “solder low components to high components” maxime, we first drop the 1N4148 diodes to D1 to D3 on the lifted PCB, aligning the dot on the diodes to the dot on the PCB (photo 2). Turn over the PCB, cut the wires short and solder. You can “tack” the diodes with a short piece of adhesive tape to make sure they don´t fall out, as they are actually thinner than the already presoldered stm32 chip.

* For sanity reasons, use your multimeter to measure the resistor values and drop them into these destination slots:

27 Ohm (red purple black gold) to R9 and R10

220 Ohm (red red brown gold) to R20, R21, R22, R25, R26 and R27 

1 kOhm (brown black red gold) to R11, R13, R14, R18 and R23

2.2 kOhm (red red red gold) to R7 and R8

4.7 kOhm (yellow purple red gold) to R19 and R24 

10 kOhm (brown black orange gold) to R12

100 kOhm (brown black yellow gold) to R1

Do not drop R15 yet, as this resistor needs to be inserted vertically - we will add this one later as we add higher components.

Tack the resistors with tape (photo 3), turn over the pcb, cut the wires and solder. Try to solder quickly (not using more than one to two seconds per solder point) and “in rows” avoiding too much solder.

* When finished, your PCB should look like photo 4.

[Hawkeye]

Step 4: Core32 - Solder Ceramic Capacitors, SIL Sockets, Crystal, Bridge Rectifier and IC Sockets

Parts used:

Core32 Module PCB (from step 3)

Core32 Parts Kit (from step 3)

Adhesive tape (e.g. tesa tape)

Description:

* Lift the PCB, so that you can easily drop components.

* Drop two 33 pF ceramic capacitors at C1 and C2.

* Drop nine 100 nF ceramic capacitors at C3, C4, C5, C6, C7, C11, C12, C14, C16.

* Drop a 330 nF ceramic capacitor at C9.

* Photo 1 shows the proper locations for these ceramic capacitors.

* Drop the 5-pin SIL sockets at R30, R31 and R32.

* Drop the 12 MHz crystal at Q1, the bridge rectifier at X1 (align flat side to the left), the 16-pin IC socket at IC2 (align the socket notch to the top) and the 8-pin IC sockets at IC4 and IC5 (aligh notches to the left).

* Photo 2 shows the proper locations for the above components.

* Tack everything with adhesive tape, turn the PCB over, cut the wires and solder.

[kristal]

go, go, go!

[Hawkeye]

Step 5: Core32 - Adding “the Rest” aka Pots, R15, Resistor Arrays, SIL Headers, T1, DIL Housings, Polarised Capacitors, 3.3V Regulator

Parts used:

Core32 Module PCB (from step 3)

Core32 Parts Kit (from step 3)

Additional SIL header (40 pin sil header e.g. from Reichelt)

Adhesive Tape (e.g. tesa tape)

Description:

* Insert the 10 kOhm trim potentiometers into P1 and P2 and solder (photo 1)

* Bend the remaining 470 Ohm resistor and insert into R15 as shown in photo 2 and solder.

* Insert a 1k Ohm resistor network (“102”) into R33 aligning the point to the left (as marked on the PCB), insert the 10k Ohm resistor network (“103”) into R2 also aligning the dots. Tack with tape temporarily (photo 3) and solder. If you want to check with your multimeter, measure the “dotted” pin against the other pins.

* Insert and solder (can tack them with tape) the external connector SIL headers (you can break the 40-pin connector into smaller pieces by using your fingernail or a knife) as follows:

2-pin into J1 - external power input (we won´t use it) 

2x2-pin into J22 - connection to the off-board USB socket

2-pin into J2 - 5V input from SEQ PSU (step 2) - for sanity reasons, I have replaced the standard header later on by a polarized connector - you can do that now :-)

4-pin into J4 - IIC MIDI Module connector

4x3-pin into MIDI IN1, OUT1, IN2, OUT2 - connection to the off-board MIDI sockets

3x3-pin into J24, J25, J26 - voltage selectors for serial ports

2-pin into J27 - if jumpered, the bootloader holds (not executing a crashed app), enabling usb reflashing

3-pin into IC6 - connection to the off-board 7805 voltage regulator

2-pin into STATUS - connection to the off-board power LED

* After adding all headers, you can compare your PCB with photo 4.

* Bend the legs of the BC337 transistor and add it to T1 so that the flat side of the transistor points to the top of the PCB and solder (photo 5)

* Now it is time to populate all DIL connector housings, just populate according to the notch indicators on the board. It is not necessary to populate J3. Turn it over and solder, do it quickly and in “rows”.

* Populate C10 with the 47µF capacitor aligning the minus pin of the cap to the other pin than the “+” marked pin on the PCB. Likewise, populate C13 with 100µF and C17 with 10µF. Turn over and solder. See photo 6.

* Insert the 3.3V regulator LF33CV to IC7, aligning the metal outside to the left and solder (photo 7).

* Populate and solder C8 with the 2200µF capacitor aligning the minus pin of the cap to the other pin than the “+” marked pin on the PCB.

* Finished soldering, now let´s insert the other parts…

* Insert the two 6N138 optocouplers into IC4 and IC5 aligning the marked dots to the left

* Insert the 74HC595N into IC2, aligning the notch to the top

* Do not fill R30 SIL sockets

* Jumper J24 to 3.3V (SD Card)

* Fill R31 SIL sockets with the 220Ohm resistor network (“221”) aligning the dot to the dot on the PCB

* Jumper J25 to 5V (DOUT/DIN modules)

* Fill R32 SIL sockets with a 1kOhm resistor network (“102”) aligning the dot to the dot on the PCB

* Jumper J26 to 5V (AOUT module)

* Turn over the PCB and create two connection wires as shown in photo 8. This direct capacitator connection is necessary when more than 100mAs are used by the +5V chain, and 5V are fed directly into J2.

* Finished work on the Core32 PCB Smile! Grab a cool drink and compare your result with photo 8.

Notes:

We will populate the MIDI ports, USB ports, power socket, USB socket and the power LED on separate boards, so we added additional headers.

The 5V voltage regulator 7805 is not necessary as we provide the core by +5V power directly

We do not need to populate J3 (JTAG wiggler) which provides a means for flashing the STM32, SmashTV has already done this for us

We will not add the J17 header, as we always want power from an external power source (not populating this jumper avoids problems when accidentally usb power was selected there and an external power source was connected)

Also, J18 is unpopulated, as this would be a connector to the CAN bus, which cannot operate parallel to USB.

Finally, J23 is unpopulated, as this one is only necessary for RS232-bootloading, which we are not keen on.

[Hawkeye]

Step 6: Core Case Works: Preparing for the MIDI Socket Backplanes

Parts used:

1541-II case (from step 1)

1541 Power Switch (from step 1)

1541 Power Jack (from step 1)

10x15cm Vector board (Any electronics store or Reichelt)

10x PCB-mounted MIDI jack (e.g. AVI Showtech, can use the MIDI jacks that were part of the Core32 module package and the MIDI IIC module packages)

6pcs M3 nylon washer (any mechanical store or Mouser)

6pcs M3 nut (any mechanical store or Reichelt)

6pcs M3x12mm screw (any mechanical store or Reichelt)

6pcs 5mm M3 hex standoff (any electronics store or Reichelt)

6pcs 30mm M3 hex standoff (any electronics store or Reichelt)

Bench drill or hand drill with 2mm, 3mm and 4mm drills

Dremel tool with cutting wheel

(Mechanical) fret saw or hot wire cutting tool

Sanding Paper (K180 class) attached to a flat thin surface

Mechanical pencil (0.5mm)

Description:

* Using the dremel with a cutting wheel, create two pieces of vector board with sizes 150x45mm and 138x45mm. Save the 10mm residue.

* Test component placement on the vector boards as shown in photo 1. Use a 2mm drill for the stabilizing pins of the usb socket. Remove the power switch again.

* Mark a few standoff zones as shown in photo 2 and use a mechanical pencil to draw the drill positions in the case. Drill the case and with a 2mm drill, then with the 3mm drill. Also make sure that the standoff positions do not conflict with the 1541-II rubber feet… I had to relocate the position for the lower left standoff hole. Drill the standoff points on the vector board with a 3mm or 4mm drill.

* Test-install the lower backplane by inserting 12mm M3 screws from the bottom, add a plastic washer and a M3 nut to achive the correct height, then add the backplane vector board, and then a 30mm standoff (photo 3).

* Draw in saw zones for the fret saw with a pencil by turning the assembly on the side and estimating required space. Remove the backplane again (photo 4) and saw. You can use a fixed guide for the linear saw movements (photo 5), but it will likely not be 100% perfect (photo 6). Use sanding paper on a flat thin surface to correct the worst irregularities (photo 7)

* Drill the upper vector board (I used a 3mm drill this time, as the 4mm was a little big) and test-install the upper connector backplane by adding a row of 5mm hex spacers and plastic washers on top of the 30mm spacers, adding the vector board screwed with 12mm screws (photos 8 and 9)

* Repeating the above steps, mark the saw zone of the 1541 case top, saw, sand and install (photo 10). Note, that for extra bling, I decided to leave some room on the right side of the upper vector board for a later LAN port extension - therefore the larger cut out.

Behold the world´s - first 1541-II with USB connector and 10 MIDI ports. :-).

[kristal]

:frantics: .;*:._ yay, another entry _.:*;.:frantics:

[Hawkeye]

Step 7: Core Case Works: Prepare for Core32 and the AOUT_NG Module

Parts Used:

10x20cm Vector board (any electronics store or Reichelt)

Core32 Module (from step 5)

4x IIC MIDI PCB (AVI Showtech)

1x AOUT_NG PCB (AVI Showtech)

12pcs M3 Nylon washer (same as in step 6)

6pcs M3 20mm hex standoffs (any mechanical/electronics store or Reichelt)

6pcs M3 8mm hex standoffs (any mechanical/electronics store or Reichelt)

4pcs M3 5mm hex standoffs (from step 6)

12pcs M3 12mm screws (from step 6)

4 pcs M3 8mm screws (any electronics store or Reichelt)

8 pcs M3 nut (from step 6)

Dremel tool with cutting wheel

Bench drill or hand drill with 2mm, 3mm and 4mm drills

Mechanical pencil (0.5mm)

Description:

* Using the dremel, create a vector board with size 100mm x 175mm

* Place the core and two MIDI modules on the vector board as shown in photo 1. Mark the six standoff zones depicted as crosses in photo 2.

* Turn over the 1541 bottom case and lay the prepared vector board on top, aligning it as shown in photo 3. Note: Take your time aligning… make sure, that the vector board, as well as the modules will fit in the case from the other side as depicted in the following pictures.

* Mark the six drill spots with a mechanical pencil, make sure not to move the vector board while marking :-).

* Drill the case, first with a 2mm, then with a 3mm drill (photo 4). In the most unlikely event that something does not fit, you can use 4mm drills to create more movement room for the screws.

* Drill the vector board, first with a 2mm, then with a 3mm drill.

* Hold your breath and install, inserting a 12mm screw from the back, adding a nylon washer, adding the Core32 module, adding 20mm standoffs. The two right standoffs require two nylon washers to compensate for the thickness of the Core32 PCB. Attach the upper vector board with 12mm screws from the top and 8mm hex standoffs. See photo 5. Fits neatly :-).

* Mark additional drilling holes and the cutout zone for cable gateway on the vector board as shown in photo 6.

* Take off the upper vector board, drill at the marked positions with a 2mm and then a 3mm drill and cut the cable gateway area with the dremel tool. Test-install the AOUT_NG PCB by putting in 12mm M3 screws from the back and adding 5mm spacers, add the PCB and fasten with M3 nuts.

If you are as eager as myself to fire up that core, follow the next steps, where we will cut the preparations and concentrate on just that :-).

[Hawkeye]

Step 8: Connecting The Power Supply and Powering On for the First Time

Parts Used:

Core32 Module (from step 5)

MBSeq PSU (from step 2)

1541 power socket (from step 1)

1541 serial data cable (used as power cable)

5-pin PCB Interconnector plug, jack and cable (e.g. from Reichelt)

2-pin SIL housing and headers (power connector to J2 of the Core32 PCB) (e.g. from Mouser)

A few centimeters of slightly-thicker-than-ribbon-wire wire

A multimeter

Your favorite soldering equpiment

Description:

* Unscrew the lower MIDI connector backplane and solder all components, so that they won´t fall off (photo 1).

* Now plug in the MBSeq PSU from step 2, flick the power switch and measure the header pins with your multimeter switched to AC voltage measurement. You should be able to determine two GND pins, two +5V pins, one +12V and one -12V pin.

* Solder the connections between the power socket and the power switch as depicted in photo 2. Attach to one +5V pin and one GND pin.

* Add a 5-pin PCB interconnector header as visible in photo 3.

* Now solder the connections from the power switch to two pins of the 5-pin PCB interconnector. Once again, use your multimeter to measure which of the pins is +5V and which is GND, when powered on. Plug in the interconnector plug and connect to J2 of the Core32. You can use a two-pin PCB-interconnector for that or SIL headers and cases.

* If you want to test, you can temporarily crimp a LED in a 2-PIN SIL housing and flick the switch. If the LED flashes three times and then stays on, the Core is alive and you did well - have a cold beverage to celebrate :-).

Note:

Using the slightly-thicker-than-ribbon-wire wire for the power rails is probably pure insanity and may not be necessary…

[Hawkeye]

Step 9: Connecting the lower Backplane USB and MIDI Ports, Flashing MBSeq via USB, Testing MIDI

Parts Used:

Core32 Module (from step 5)

Lower connector backplane (from step 6)

16 pin DIL-header or 2x8 pin SIL-header (e.g. from AVI Showtech, but every electronics shop should carry this)

16 pin flat ribbon cable (e.g. from AVI Showtech, but every electronics shop should carry this)

16 pin female IDC connector (e.g. from AVI Showtech, but every electronics shop should carry this)

2pcs 2-pin SIL housing (USB connector) (e.g. from Mouser)

4pcs 3-pin SIL housing (MIDI connectors) (e.g. from Mouser)

16 pcs SIL housing crimp terminals (e.g. from Mouser)

A piece of colored tape to use as a connection orientation label

USB Cable (for flashing and testing)

2x MIDI Cables and a computer MIDI Interface (for testing)

A running version of MIOS Studio 2.x+ (for flashing and testing)

Description:

* Install and solder a DIL header to connect the lower backplane to the core as shown in photo 1.

* Wire the USB connections using cable of appropriate length, as shown in photo 2. Keep the cables flat to the vector board.

* Wire the MIDI connections as shown in photo 3. When routing cables, stay clear of the hex standoff holes.

http://discourse.midibox.org/t/topic/14451

* Connect the cable to the core and the lower backplane. Turn the whole assembly over and measure connectivity between every solder point where the original connectors should have been placed on the core32 board and their real location on the lower backplane vectorboard. They should be just prolonged 1:1 and there must be no solder bridges. Take your time to check that.

* When fully installed, your case should look like photo 5. You can use small pieces of tape on the connectors and on the base board to mark correct plug alignment.

* Connect the USB port to your computer. Power-on the sequencer. If everything was cabled correctly, your OS should list 4 new MIDI IN and OUT ports: one USB-MIDI port pair, and three MIDI port pairs provided by the Core32.

* Start MIOS studio and select the USB Midi port pair as MIDI IN and MIDI OUT.

* Press “Query”. The core32 delivers some nice status information, such as memory information and serial number.

http://discourse.midibox.org/t/topic/14708

* After the flashing procedure, the sequencer will reboot and the MBSeq app will be executed on the core. You can now use MIOS Studio to type “help” in the command section to see some feedback from the MBSeq app itself. You can also type in “play” for a first visual inspection - the attached LED will start to flash (beat indicator) ;-).

* To test the MIDI ports, disconnect the sequencer from usb and connect MIDI cables to another connected USB/Firewire MIDI interface. Wire up MIDI IN1 and MIDI OUT1 or MIDI IN2 and MIDI OUT2 to your other USB/Firewire MIDI Interface and select the USB/Firewire Interfaces´ MIDI ports in MIOS Studio as In- and Out-ports. Now press query, you should see the exact same information as was delivered before via USB, but now over MIDI. Test the other port pair, too. Photo 6 shows MIOS studio talking to the MBSeq via a MIDI Port (I used my FastTrack USB Interface). I clicked on “Query” (middle left window) and typed in “help” in the lower command window.

If everything works, you have an operational MBSeq - ok ok, no control surface yet…

[project.hex](< base_url >/applications/core/interface/file/attachment.php?id=8017)

[Hawkeye]

Step 10: Test a VFD

Parts used:

* Futaba VFD M402SD10FJ (buy two, i got mine from mercateo.com for less than 50€ per piece)

* 14 pin DIL-header or 2x7 pin SIL-header (e.g. from AVI Showtech, but every electronics shop should carry this)

* 16 pin flat ribbon cable (e.g. from AVI Showtech, but every electronics shop should carry this)

* 2pcs 16 pin female IDC connector (e.g. from AVI Showtech, but every electronics shop should carry this)

Description:

Being nosey parkers, we want to quickly check how the vfds perform, so lets hook one up (even if that means, that we have to change the display cable later on).

* Solder the DIL header to the backside of the VFD as shown in photo 1.

* Create a display cable as shown in photo 2 - it is important to note the twist. Photo 3 clarifies things and shows how to plug-in the cable. Note, that the VFD only needs 14 pins (no backlight voltage pins 15 and 16), make sure that you plug-in the cable, so that pin 1 (marked with an arrow - see photo 1) correlates to the the first pin of your cable coming from the core32, so that the unused pins of the idc connector are on the other side than the arrowmark. In the pictures, pin-1 is the dark blue colored ribbon.

Turn on the sequencer and enjoy ;-). No knobs to turn and no buttons to push yet… but very nice. You can repeat the procedure with the other VFD, of course.

[Hawkeye]

Step 11: Attaching a SD Card

Parts used:

* SD card of your choice (SDHC worked in my tests), does not need to have much capacity, but choose a trusted brand

* 10-pin ribbon wire (e.g. from AVI Showtech, but every electronics shop should carry this)

* 2pcs 10-pin IDC connector (e.g. from AVI Showtech, but every electronics shop should carry this)

* 10-pin DIL header (e.g. from AVI Showtech, but every electronics shop should carry this)

* 20-pin DIL housing from Core32 parts kit

* a few small cable binders

* a multimeter or a connection beeper

* your favorite solder equipment

Description:

* In fact, I really don´t like MicroSD cards for reliability… but that is another story… also, I don´t want the SD card to be removable from the sequencer, backups can be created by entering usb file transfer mode or by using the sd reader app… Presenting another low-cost way to attach a SD card without soldering to the SD card and therefore allowing for replacability in case of a failure.

* First, let´s have a look at the goal of this step - see photo 1. Using the unused 20-pin DIL connector housing from the Core32 parts package (we did not poulate J3) and a small cable binder through the side holes of the DIL housing, we create an assembly as shown. To fasten the cable binder, just press on another cable binder top on the end of the installed one and cut the rest off. Cable binders are not really necessary, you can also bend the DIL housing pins for more firm contact, if necessary.

* Create a short 1:1 interconnection cable using two IDC connectors and a few centimeters of 10-pin ribbon wire (photo 2). You may splice the ribbon pins, twist the wires and fasten with cable binders to better handle the 90-degree turn.

* Disassemble the lower backplane, turn it over and solder the 10-pin DIL header and the 20-pin DIL connector.

* Use the SD Card wiring diagram from ucapps.de to route cables as shown in photo 3:

SIL header 1 (purple) goes to horizontal solder point 9

SIL header 2 (grey) goes to horizontal solder point 6

SIL header 3 (white) goes to horizontal solder point 7

SIL header 4 is unconnected

SIL header 5 (black) goes to horizontal solder point 10

SIL header 6 (brown) goes to horizontal solder point 5

SIL header 7 is unconnected

SIL header 8 (red) goes to horizontal solder point 8

SIL header 9 is unconnected

SIL header 10 (yellow) goes to horizontal solder point 4

* You can remove and reinstall the SD card by just pulling a little on the cable binder - it is flexible enough. Attach jumpers as shown in photo 4.This ensures, that the SD card can only be inserted properly.

* Do not turn on power yet - let´s first test the connectivity - using your multimeter or your connection beeper and a spare 10-pin DIL header temporarily inserted into the core32-side IDC connector, measure each connection and compare that it matches with the SDCard wiring diagram from ucapps.de - also check for unwanted solder bridges.

* When everything is ready, turn on and enjoy TKs friendly message about the recognition of your new SD device (photo 5).

Note:

* Before powering on, make sure you have jumpered J24 to 3.3V - otherwise you might burn your SD Card

* There are nice tutorials for other ways to connect SD cards on ucapps.de, available here: http://ucapps.de/mbhp_sdcard.html

[Hawkeye]

Step 12 (optional): Coding Intermezzo (or: two screens working, hooray!)

Parts required:

Your favorite gcc compiler

Calmness, tao and a supportive partner

Description:

Last week I managed to get one"cheap" Futaba VFD up and running thinking all my problems would be solved, by switching the normal 8-bit character lcd driver into 4-bit mode (as the display contained replaced characters in 8-bit motorola mode). Pah, when test-attaching the second display and thinking it would be as easy as that, both displays stayed dark.

Thinking of a power (surge) problem at first, I reworked the power supply of the Core32 (I have documented this now in step 2…), supplying up to 2A of 5V direct to the Core32 - and of course that did not help, both displays still stayed dark.

Suspecting that “cheap” really meant “cheap in a compatibility-with-established-standards-way”, I tested everything including switching back to 8-bit mode (garbage output), mixing the VFD with a classic LED backlit LCD - this worked, depending on which port the classic LCD was connected to… I was near to pulling my hair, not at all understanding what the problem was.

At some time I had the idea, that those displays might not be able to share the same control lines (RS, RW - E1 is already separated from E2), i therefore moved these lines to the by then “unoccupied” DB0-DB3 data lines (the 4-bit necessity proved to be the way out of this mess by giving us a few free data lines). My 9-wire-per-vfd cabling looks like this:

* J15A DISPLAY 1 WHAT

 * 1 -> 1 GND

 * 2 -> 2 VCC 5V

 * 4 -> 4 RS

 * 5 -> 5 RW

 * 6 -> 6 E

 * 11	-> 11 DB4 	

 * 12	-> 12 DB5

 * 13	-> 13 DB6

 * 14	-> 14 DB7

 * -------------------------

 * J15B	DISPLAY 2	WHAT

 * 1 -> 1 GND

 * 2 -> 2 VCC 5V

 * 8 -> 4 DB1 -> RS 

 * 9 -> 5 DB2 -> RW

 * 10	-> 6 DB3 -> E

 * 11	-> 11 DB4

 * 12	-> 12 DB5

 * 13	-> 13 DB6

 * 14	-> 14 DB7

Also I had to change much of the app_lcd driver to “emulate” the control lines for the second display on the unused data lines 0-3 (photo 1)…

What should I say… it worked in the end (photo 2), it just had to… but I guess I spent more than 20 hours on the problem. Would have been cheaper to buy more expensive Noritake VFDs :).

I´ve attached a changed app_lcd.c for the at least incompatible but probably quickly hacked holtek 16514 vfd display driver chip. If permitted by TK after a code review, I would add this to the source repository for those poor people like me, who own that chip ;-). I´ve also reattached a now twin-futaba-vfd-capable version of mbseqv4 beta 31 for your convenience.

[app_lcd.c](< base_url >/applications/core/interface/file/attachment.php?id=8033)

[project.hex](< base_url >/applications/core/interface/file/attachment.php?id=8034)

[Hawkeye]

Step 13: Preparing the Case for the IIC MIDI Modules and the DIN/DOUT Sandwich

Parts used:

* A dremel tool with a cutting wheel

* A bench drill or a hand drill with 2mm and 3mm drills

* 2pcs MIDI IIC module PCBs (to find standoff drill positions) (AVI Showtech)

* DIN or DOUT PCB (to find standoff drill positions) (AVI Showtech)

* 12 pcs M3x12mm screws (from step 6)

* 12 pcs M3 plastic washers (from step 6)

Description:

* First, remove all components from the case and using your dremel tool, cut away the plastic edge (photo 1), which is in the way of the MIDI modules (photo 2).

* Reassamble and lay two IIC MIDI PCBs and a DIN or DOUT PCB out as shown in photo 3. Use a pencil to mark the center of the PCB holes to mark the new drill hole positions.

* Using a 2mm drill first and a 3mm drill afterwards, create the 12 additional standoff drill holes.

* Insert M3x12mm screws and place plastic washers on top (photo 4).

The case is now ready for the installation of these modules.

[Hawkeye]

Step 14: Building four IIC MIDI OUT Modules

Parts used:
* 4pcs MIDI IIC PCB **** ( AVI Showtech )
* 4pcs MIDI-preflashed PIC16F88 (AVI Showtech)
* 16pcs 220 ohm resistor (any electronics store or Reichelt)
* 4pcs 20MHz crystal (any electronics store or Reichelt)
* 8pcs ceramic capacitor 15pF (any electronics store or Reichelt)
* 4pcs ceramic capacitor 100nF (any electronics store or Reichelt)
* 4pcs 18-pin IC sockets for PICs (any electronics store or Reichelt)
* 4 x 14 pins of DIL header **** (any electronics store or **** AVI Showtech**)**
* 4 x 7 pins of SIL header (any electronics store or AVI Showtech** )**
* 4pcs SIL-header jumpers (any electronics store or AVI Showtech** )**
* 4pcs electrolytic capacitor 10 uF 35v (any electronics store or Reichelt)
* 8pcs M3 10mm hex standoff (from step 6)
* 8pcs M3 5mm hex standoff (from step 6)
* 8pcs M3 12mm screw (from step 6)

Description:
* For efficiency reasons, you can work on all four PCBs at once, just repeat the below steps for every board:
* First drop the 220 ohm resistors (red, red, brown, gold) into R1, R2, R9 and R10 (photo 1), turn over the PCBs and solder.
* Continue with the crystal, which should be placed at Q1 (photo 2).
* Now drop and the solder two 15pF ceramic capacitors to C1 and C2 and one 100nF ceramic capacitor to C4 (photo 3).
* Add the IC socket and solder it (photo 4)
* Now drop and solder a 10-pin DIL header to J2, a 4-pin DIL header to J3, two 2-pin SIL headers to the left and right LED slot, and a 3-pin SIL header to the MIDI out port (photo 4).
* Finally, add the 10 uF electrolytic capacitor observing polarity (connect the “- pin” opposite to the “+” symbol on the PCB).
* Insert the PIC, aligning its notch with the notch on the PCB. Photo 5 shows a completed MIDI-out module.

* Now, jumper J3 to four different values for the four PCBs (photo 6 - from left to right the modules will be MIDI OUT4, 5, 6 and 7).
* Install the MIDI out modules in order MIDI OUT 4 on the lower right, MIDI OUT 5 on the lower left, MIDI OUT 6 on the upper left and MIDI OUT 7 on the upper right. Photo 7 shows the assembly stage (three modules installed). Use 10 mm hex standoffs on the lower PCBs and fasten the upper PCBs with 12mm screws and additional 5mm hex standoffs from the top (you can also use single 15mm hex standoffs, of course).

 

Addendum:

I forgot to solder in resistors R4/R5 (10k each) and learned the hard way, that proper IIC address selection is not possible without them :-). I´d recommend you install them, if you want to use more than one IIC module in your SEQ

[T.K]

Great work!

I hope to see your MBSEQ next sunday - not only to evaluate the performance of the VFD display (and to integrate app_lcd.c), but also to check why the incorrect RAM size is displayed:

The RAM value is stored at a special STM32 memory location, it seems that your chip works different from others.

Best Regards, Thorsten.

[Hawkeye]

Step 15: Prepare the DIN/DOUT modules.

* 3pcs DIN module PCBs and parts kits (AVI Showtech)

* 3pcs DOUT module PCBs and parts kits (AVI Showtech)

* 90-degree SIL headers (50 pins per module required) (Reichelt)

* 90-degree DIL modules (10 pins for the first DIN and DOUT module needed) (Reichelt)

Description:

* Building the DIN/DOUT modules is really straightforward. Look at the nice board overviews available at SmashTVs site: http://www.avishowte…mbhp_dinR5.html and http://www.avishowte…bhp_doutR5.html respectively.

* As we have a slim case, we solder the shift register ICs directly to the PCB. Parts and PCBs are cheap, in case of a failure, you can replace a whole module or desolder ICs.

* You can bend the DIN resistor arrays before soldering to allow for an even “flatter” module :-).

* Also, install 90-degree angular types of headers, for better sandwich wiring installation. See photo 1 for a completed DIN module and photo 2 for a completed DOUT module. Note, that the angular “output headers” have been inserted differently than you would normally do it. They are providing lifted “solder pads” for the wires to the CS. Cut any wires on the back of the PCBs very short, so that we can sandwich properly :-).

* Attach 90-degree DIL headers to J1 of the first DIN and DOUT module respectively - so that we can use a cable with IDC plugs to connect to the core - photo 3 shows the first DIN module with an angled DIL header at J1 and the two “chained” DIN modules with angled SIL headers.

* As with the MIDI modules, you can build the DIN and the DOUT modules in parallel, first soldering all capacitators, then the resistor (networks), then the ICs, then the SIL/DIL headers, this saves some time…

[Hawkeye]

Step 16: Preparing the DIN/DOUT Module Cable Connections to Core32 and Control Surface

Parts Used:

* Some meters of coloured 10-pin ribbon cable (connection to the breakout-box control surface) (AVI Showtech)

* 3pcs 10-pin IDC connectors (AVI Showtech)

* The 1541 drive front panel from step 1

* Some time and your favourite soldering equipment

Description:

* Create an Y-Cable with three IDC connectors, to connect the DIN and DOUT modules to J8/J9 of the Core32. Splice the wires and use your fingernails or a screwdriver to push the wires into the opened IDC metal crimp connectors as shown in photo 1. Photo 2 shows the assembled cable.

* Use your multimeter to measure the correct pinout of your cable reviewing the Core32 J8/J9 diagram and the DIN/DOUT module diagrams. Make sure, that J8 (upper row of the IDC connector on the Core32) goes into the first DOUT module, whereas J9 (lower row) goes into the first DIN module. Mark the plugs to avoid later confusion (photo 3).

* Solder 10-pin ribbon wires to the output pins as shown in photo 4. The cables should be as short as possible, but as long as necessary to connect your external control surface board. Photo 5 shows a DIN module with spliced and bundled ribbon wires to the control surface. If possible, use colored ribbon wires and use the same color order everywhere (e.g. black for pin 1, white for pin 2, etc..). When you have soldered 6x4x10 wires, let´s call it a day

* If you experience any problems with your buttons/encoders/LEDs later on, make sure to put arnolds (terminators ;-)) on the end of both DIN/DOUT chains as depicted here.

* When you install the DIN/DOUT sandwich in the next step, the wires to the control surface should be led out of the floppy door. You can reuse the floppy front panel LEDs for status indication (photo 6) - let´s connect the green (ex 1541 POWER) LED to the aout_ng (we did not build it yet ;-)) status led and the yellow (ex 1541 DRIVE) LED to the Core32 power LED (which will blink in sync, when a pattern is played).