I just went through a two days session trying to find out why my Roland E96 never worked with a GOTEK drive. While I don't know much about the Yamaha I am pretty experienced by troubleshooting the GOTEK at this time.
All the GOTEK drives are equal. There is no difference between an AMIGA GOTEK and a Yamaha GOTEK. The operations are defined in the firmware. Today we have a generic firmware that works with all GOTEK hosts.
You could start by flashing the lates firmware from flashfloppy to the GOTEK.
https://github.com/keirf/FlashFloppy/wiki/Downloads
I would pick the latest version v13.3a
Plus follow the directions in how to install the firmware.
Then create an image of exactly 737280 bytes or 1474560. It does not matter what is in these files as you want to let Yamaha format it. The names DSKA0000.IMG, DSKA0001.IMG ... are the default way to name these.
Then create a file FF.CFG that resides in the root directory of the USB stick. Don't change anything in this FF.CFG file (except the signal usage pin02, pin34)
Here I was trying out different options for days until I found out that the only thing I needed to do was to change two variables:
pin02 = dens
pin34 = rdy
After these changes my Roland E96 was able to read/write both 720k and 1.44m floppy images correctly.
The options you have for the pins are
Values: auto, nc, low, high, rdy, nrdy, dens, ndens, chg, nchg
My guess is that you need to assign rdy to (pin02 or pin34) to get it to work. The other could be (nc, chg or dens).
A good extra tool is to also install the log-firmware from /apt/log. It will tell in real text what the GOTEK is doing. After you have added the logfile then the startup is no longer FF but Lo. Once everything works you can flast the original firmware again to get back to normal.
The log produces a file called FFLOG.TXT to the USB drive. Here is an example from one of my runs:
Code:
Build: Mar 13 2020 08:20:14
Board: Standard
Config: Factory Defaults
Interface: Shugart (pin2=chg, pin34=rdy)
Display: 2-Digit LED
> USBH_USR_Init
> USBH_USR_ResetDevice
> USBH_USR_DeviceAttached
> USBH_USR_ResetDevice
> USBH_USR_DeviceSpeedDetected
> Device speed: Full
> USBH_USR_DeviceDescAvailable
VID : 152D
PID : 2338
> USBH_USR_DeviceAddressAssigned
> USBH_USR_ConfigurationDescAvailable
> Class connected: 08 (MSC)
Manufacturer : JMicron
Product : USB to ATA/ATAPI bridge
Serial Number : 000001D91CA0
> USBH_USR_EnumerationDone
> USBH_USR_UserInput
Cache 104 items
Config: Written to Flash Slot 9
0:F: 'DSKA0144.HFE'
Cache 104 items
Mode: Native
Current slot: 0/0
Name: 'DSKA0144' Type: hfe
Attr: 20 Clus: 000015f0 Size: 4215808
[lost 82067]
191 (4096)... 8053 us
Write 8192-12287 (4096)... 8086 us
Write 12288-16383 (4096)... 8108 us
Write 16384-20479 (4096)... 8016 us
Write 20480-24575 (4096)... 8019 us
Write 24576-28671 (4096)... 8004 us
The problem in my case was that all posts on the net claimed that it is enough to select "shugart" or "ibmpc" and I am ok. The "ibmpc" did not work at all as it had pin02=nc and pin34=chg. The "shugart" appeared to work occasionally but after power on/off it just said "unformatted disk".
While I have no clue of how a Yamaha PSR-620 works my guess is that you should first try to find out where the rdy pin needs to be. And then find out what the 2nd pin does.
If the Yamaha PSR-620 is about the same age as Yamaha DX7II-FD then you may need to do a small hw mod that is described in
https://github.com/keirf/FlashFloppy/wiki/Host-Platforms#yamaha-dx7ii-fd
I wish you luck with the GOTEK. My GOTEK was in a cupboard for many years and now I finally started to work with it as I am stuch home in isolation. Here is a small isolation rock'n'roll played by me, and playbacked through GOTEK on my Roland E96.