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Cheap development boards for Mutable builds?
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author Cheap development boards for Mutable builds?
Silesius
Hi, I’ve been wanting for some time to build some of the Mutable “digital” stuff. I’ve built and adapted some of the analog modules; it’s very nice all that information is online. However, I have zero experience with programming mcu’s etc.
I managed to buy two Grids smd boards with the ics already programmed from Synthcube... that was some time ago. Now, I think nobody sells the programmed chips anymore.
I’m writing all this because I’ve just destroyed said chips in my first (and horrible) smd experience very frustrating
Looking at the schematics, the analog part of some of them (the more “digital” ones”) is very simple. I’m thinking I can build the analog parts in a piece of strip board very easily.
My problems (and my questions) come mostly with programming the mcu’s. For example, let’s say I want to build a braids. It uses a stm32f103 mcu. Can I buy something like this, flash it via usb with the code in GitHub and place in my stripboard with the analog part?
Dev board

If this is everything that’s needed I will be a happy person. I’m building a mono synth and one customised Braids would be wonderful.
fg
hello,

i 'm not finished braids because i don't have received the dac yet, but for the first step, concerning the bootload, i use a standard stm32f103 + stlink usb key and upload braids.hex in it with no problem. (no message error)



i begin to search the pinout, i skip the lcd but easy to add



i builded grids and it runs with an arduino nano, no problem

hope i could help, and pardon my french
Silesius
Hey Fg, many thanks for your reply. That’s very useful information for me. But do I need that stlink usb key to upload the software? I thought since there’s an usb connector in the dev board, I could use it connected directly to the computer. But if I need to buy that no problem, I can do it as well.
fg
you re right ! i didn t try by this way,

probably because, i usually don't connect any cards on my computer, to avoid the driver problems, i prefere install & use 1 usbtiny with avrdude (for exemple) for flashing a lot of atmega, attiny ... so i install one stlink (at 2$ on ebay)
Silesius
Ok, I understand.
So, to confirm, do I just need one of that dev boards (and maybe an stlink) to flash the braids software (and the computer of course)? No more hardware involved?
Would I be able to build a Grids with one of these? Atmega328 board
Another thing I'm not sure is what happens if the crystals and speeds are different from the ones in the Mutable schematics. Do I have to change the crystals?
I think I'm going to focus on building a Braids and a Grids with this two boards, and hopefully learn a little about all this stuff. I've been building analog modules for almost ten years, but this is a big challenge for me. Im veeery excited with the possibilities smile
Last thing I have to solve is finding a way to install the dac8551 in my Braids board. I've found a dip version of the ADC chip, but there's no through hole package for the DAC... Maybe I can find some breakout boards or something like that....
fg
grids:
ive just upload grids software*** on an standard arduino nano without modification, but you are right again, the quartz speed is different but my grids works very well. i don't use the lm4040 too but a simple zener diode 5V to generate -5v and the cv reponse is ok too.

/!\ f*u*s*e avrdude -c usbtiny -p m328p -U flash:w:grids.hex -U lfuse:w:0xff:m -U hfuse:w:0xd8:m -U efuse:w:0x05:m -U lock:w:0x2F:m

efuse ask to change ? i answer "no" but i think that default value 0xff is preferable

i did avrdude -c usbtiny -p m328p -U flash:w:grids.hex -U lfuse:w:0xff:m -U hfuse:w:0xd8:m -U efuse:w:0xff:m -U lock:w:0x2F:m

not shure at 100% about the internal speed clock.

braids:
i 'd like to know your ref of the dac 85 in dip8 (i commanded the smd version hmmm..... )
could you tell me what is it ? plz

thanx
Silesius
Fg, sorry, but you misunderstood me. What I have found is a dip version of the ADC (MCP3204), not the DAC... I found some adapter boards in Ebay, and I plan to use it to solder the Dac8551. Let's see how it goes...
flts
The minimal STM32F10 system development boards probably don't have a programming mode via the USB port, it's just for power. At least that's how it goes with mine. So you most probably need a STLink (v2) of some kind. Some of the official STMicro development boards (eg. the Discovery series) come with a built-in STLink v2, but the separate "stick" is of course quite convenient if you don't need an extra dev board.

You shouldn't need any extra hardware beside that. I think the "minimal board" you linked comes with 8MHz xtal like Braids uses. At worst you'll have to dig into the code and tweak some clock multipliers to get it working properly.

One thing to watch out is that the digital parts of the circuit may be quite sensitive to component placement - the MCU and most of the associated parts are already in the board you buy, but if there are issues it pays to think about the various power and ground runs and layout regarding etc. the DAC.

And yeah, the DAC is only available as TSSOP so you'll need a DIP adapter for stripboard.
Silesius
flts wrote:
One thing to watch out is that the digital parts of the circuit may be quite sensitive to component placement - the MCU and most of the associated parts are already in the board you buy, but if there are issues it pays to think about the various power and ground runs and layout regarding etc. the DAC.


Thanks for the info, I'll keep that in mind
fg
hello, with no surprise branches is ok with an atmega88PA dip-28

fuses ---- > avrdude -c usbtiny -p m88p -U flash:w:branches.hex -U lfuse:w:0xE2:m -U hfuse:w:0xDD:m -U efuse:w:0xF8:m -U lock:w:0x2F:m


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