Drive Sounds

[Manger74]

I was able to add a "Klick" sound, for Floppy & HDD activity, to the HDMI audio.
It works, but it sounds not very authentic...
Also the sound should come from the device, not from the speakers.
Would it be possible to add a buzzer or a tiny speaker to the hardware?
Could the analog mono audio on the TN20K, be used for drive sounds?

ps
I do have the tiny speaker from Sipeed somewhere...
Will try to send the "Klick" to the analog audio...
Will be interesting, to hear drive sounds directly from the device...

[Manger74]

I found some really nice drive sounds from a real Amiga, but that's too much for the NanoMig 20K, i believe...

https://github.com/robinsonb5/MinimigAGA_TC64/tree/058a79fc5061a67167c42a3e271c56814d64efea/sw/mkdrivesounds

https://github.com/robinsonb5/MinimigAGA_Experimental/tree/3e093807c7ee25386a72ec1ca3b69f467c1defcc/rtl/drivesounds

It will be more LE saving, to go with some simple synthetic noises, i assume?

[harbaum]

The Companion still contains some never-finished audio interface. The idea actually was to use this for floppy sounds and the like. But indeed, floppy sounds from the main speakers is rather silly.

But yeah, why not use the amp present on the TN20k for this? Sounds like a fun idea.

[Manger74]

How was the audio interface planned to work? Over HDMI audio?

I just found out, that the pins of the audio amplifier collide with the connection to the external BL616/M0S.
If we were using the samples, it would be nice to use the small speaker that comes with the TN20K!

But i'm looking for a more simple solution now...

My GOEX drive uses a buzzer to simulate the floppy sounds.
No motor sound, just the stepping sound of the R/W head!
The result is convincing, subtle and comes from the right spot!

Do we have an unused Pin left?

[Manger74]

How does a core know, which MCU to use?
There are 5 pins reserved for the interface to an external MCU.
Could these pins be dynamically reused for other purposes?
If no external MCU is present, other functions would be assigned to the pins?

[Manger74]

Is pin 53 unused?

edit: My friend Claude thinks, the pin could be used for a passive buzzer, although it is connected to the HDMI...

edit: 53 seems to be unused in the nano20k/nanomig.cst 😊

[Manger74]

I've got this generic buzzer at hand.
It's a piezo buzzer for 3-24V DC.
Can i use it safely for experimenting & testing purposes?

// BUZZER
IO_LOC "buzzer" 53;
IO_PORT "buzzer" IO_TYPE=LVCMOS33 PULL_MODE=DOWN DRIVE=16;

[harbaum]

Pin 53 is unused on the NanoMig.

I would not expect problems, but I cannot guarantee that directly connecting a piezzo to the Tang may not cause harm. It may be safer to add a small transistor. Is this a speaker or a buzzer? Both come in the same cases. One beeps by itself the other one needs some audio signal to make sound.

[Manger74]

Pin 53 is unused on the NanoMig.

Nice!
Yes, a transistor will be better to drive the buzzer!
Will find out, what's better for drive sounds...
active or passive, 3.3V or 5V.
Will try to find out what's on the GOEX drive!

@harbaum
@vossstef

I believe a buzzer for drive sounds on the device makes a lot of sense!
Can we reserve the pin 53 for it officially?
Will prepare the schematic and the code!
I think i can work it out...

[harbaum]

None of my cores seem to use pin 53. So i'd just be fine with this type up usage.

[Manger74]

I asked Pavel, the creator of the GOEX drive.
He recommends a passive 3.3V buzzer, driven by an NPN transistor.
I like the sound of the GOEX, so i think that's perfect!
The PWM signal will allow different pitches for HDD & FDD noises.

[Manger74]

Safety diode added...
Now the design is ready for (passive) magnetic or piezo buzzers...

[Manger74]

@harbaum

I do have a working drive_sounds module!
The HDD sounds good but the FDD not so much...

I found the speaker.c from the Gotek/Flashfloppy firmware and try to replicate that sound...

https://github.com/keirf/flashfloppy/blob/483077a26651a9b8a19959e84900577ff5b0c2c6/src/gotek/speaker.c

Would need these signals: the step of the head, floppy insert, floppy eject, motor

I found these control signals in paula_floppy.v

//disk control signals from cia and user
input		  _step, // step heads of disk
input		  direc, // step heads direction
input [3:0]	  _sel, // disk select 	
input		  side, // upper/lower disk head
input		  _motor, // disk motor control
output		  _track0, // track zero detect
output		  _change, // disk has been removed from drive
output		  _ready, // disk is ready
output		  _wprot, // disk is write-protected
output		  index, // disk index pulse

_step - would be the head stepping
_ready - disk insert?
_change - disk eject

My question is now, are these signals working on the NanoMig?
Where are _step & _motor generated? Where do they come from?
Could not find it...
Thanks!

[Manger74]

"// These are the cia's
// Note that these are simplified implementation of both CIA's, just enough
// to get Minimig going"

Maybe not all drive signals are fully implemented?

[Manger74]

Disk Drive Control Signals should come from CIA B