[WTB] Standard PCBs (CORE_STM32F4, DIN, DOUT...)

[tago]

On 12.7.2016 at 1:09 AM, latigid on said:

I would certainly not expect a newb to understand everything from the start just by looking at uCapps and the wiki. Perhaps with your efforts there some info can be clearer. It's just nice to start with a PCB that's almost guaranteed to work so you don't get disappointed.

It's simply too much info and modularity for a beginner and too easy to give up because of that.

I for one did learn some basics playing with teensy and built a little midi volume controller with a led ring and two led-buttons directly attached to the controller board. After that success (thanks to teensy) i gone over to look at shift registers/multiplexers and did a little test aiming to build a larger midi controller. But then came doubt if teensy is the best patform to do something larger. And there i am, certainly not the only one.

I debated building my own PCBs and started with Kicad. But if you are a beginner in designing and etching PCBs it seems like a project in itself (+ money for equipment). As i'll try to build the housing for my project with no cnc-mill myself, there is plenty to learn and getting tools as well. Something had to be sacrified. Therefor is getting ready made PCBs a good alternative. Maybe i will do the AINs on veroboard distributed over the frontpanel near the pots/slider, in that case no AINSER64 then.

Summary: i have no idea/equipment and will do it anyways :) There are good chances to failure.

 

[latigid on]

How many AINs were you thinking? STM32F4 has 8 ADCs and a few of us are looking into how well this works. It's easier with known voltage maximums that you define through a resistive divider like a pot rather than CV which needs protection from over- and undervoltages etc.

[tago]

Just now, latigid on said:

How many AINs were you thinking? STM32F4 has 8 ADCs and a few of us are looking into how well this works. It's easier with known voltage maximums that you define through a resistive divider like a pot rather than CV which needs protection from over- and undervoltages etc.

I'll need around 40 analog ins, let's say 6x AINSER8 modules.

The manual states:

Quote

Multiple MBHP_AINSER8 (or MBHP_AINSER64) modules are connected to J19 in parallel, and accessed by strobing dedicated chip select lines. J19 provides two chip selects (called "RC1" and "RC2"), if more modules should be scanned, common IO pins could be used for the same purpose (e.g. available at J5).

I don't understand how much i can connect without much hassle. Do you need one RCX per AINSER8 ?

[Zam]

Hi tago

Yes you need one RC line per chips, connector J19 used fort this purpose only offer two RC line by default

If you need 40 analog pot you better go with AINSER64 which use 8 multiplexer around MPC3208 for a total of 64 input, with a single RC line.

Best

Zam

[latigid on]

Exactly, every ADC chip requires select lines. Notice AINSER64 further multiplexes the inputs with 4051 chips for a single 8 channel ADC and generates a 3-bit "address" to specify what input a 4051 should scan at a given time. This is synchronised in software to map each "pot position" with its current value.