I'm not a spokesman for this product. But the price of the DrawBridge USB Floppy PCB with a new USB cable is only 25 Euros. Rob Smith makes these by hand.

https://amiga.rob...uk/waiting

Last night I was working on the Disk Reader. I was attempting to get the drive rpm data. My first few attempts failed. But I know why. I'll get it working this weekend.

I'm already working on the next phase of the project & that is decoding an Amiga track full of mfm data, converting it to binary to write to disk. Reading the mfm data will come later. But first I want to write my functions to process the data.

Apparently I can use TeraTerm to send Arduino commands to the DrawBridge Device for it to read the current track & send the mfm data. TeraTerm will collect the mfm data & save it a file as Hexadecimal data. So I can use the raw mfm data to test decoding functions on AROS.

Also, I wrote an article about the SerialDiskReader. I'll post it later.

Well, I don't have time to figure out how to do a blog or article so here is my article...

Here is my current status for this project which has been ongoing since I first
compiled the orginal c++ code for Windows 10 in late 2023 to early 2024.

Although there are probably more powerful serial terrminal applications
available, TeraTerm 5 has proven to be both powerful and easy to use. I
use it for testing and verification of the Arduino commands and I can see
the response strings the Arduino sends back across the serial COM port.

So far I setup the serial connection parameters including 2000000 baud
(2 Mega Baud which is outrageously fast!). I used Poseidon Library psd
commands same as the psd commands in the USB-to-Serial classes in
Poseidon already, to get the psd device based on Vendor ProductID &
VendorID. Based on the device I setup the Serial Write_Pipe/Read_Pipe.
The Pipe structures are needed to send and receive the Serial Data.

The first thing the SerialDiskReader has to do is attempt to sync and
request the firmware version number from the Arduino. That's because
some advanced features are only available for version 1.9 and above.
That first task has been completed. The version of my ATmega328P is
"V1,91" which I suppose is the same as "V1.91" outside of Europe.

The second task was to test the disk drive hardware by turning on the
drive motor and spinning up the disk. Then measure drive rpm which
is an advanced feature available for the Arduino V1.9 and above.

I wrote a few small functions to accomplish this. I was pleasantly
surprised to see the drive activity light come on as the drive began
to spin the disk. Hower, although I did the same test on TeraTerm,
I forgot that I need to wait a whole second before receiving the
serial data for the drive rpm from the Arduino. It needs time to
allow the disk to spin about 5 rotations to get the sync pulses to
calculate an average rotations per minute based on that data.

After turning on the drive motor I tried to read the rpm data
immediately, no wonder my program returned zero bytes for
the rpm data. I thought it had failed and the program froze
so I ended the program and started it again in the shell. But
to my surprise instead of printing the Version String which I
expected it instead printed what looked like the rpm string.

Obviously, I didn't wait a full second to receive the data so
that was my mistake, easy to fix. Second, it did actually do
the rpm test and send the data to the serial port but later.
Although I had ended my shell program the Arduino had
received it's command and it was dutifully doing its thing!
The DrawBridge Device was still connected to my PC and
when the rpm data was ready the Arduino sent it to the
serial port. But by that time I had closed my program &
restarted it. When my program tried to read the Version
it got the rpm data instead that was waiting to be read.

I learned a few takeaways from that exchange...wait for
the data to be available at the serial port and maybe put
a timeout to test the port for data and be prepared to
read small packets (1024 bytes) at a time & assemble
them into a complete buffer at the end. These things
are needed to receive high-speed mfm data across
the serial port connection. That's the next step. I have
no doubt the transaction of receiving the mfm data
from reading an Amiga Track, (track0, head0) will be
successful. Keeping that in mind I'm jumping ahead
to start processing & coverting the mfm data to the
standard binary to write to a binary file. I'll use my
trusted TeraTerm for that, hopefully. Looking at the
data in HxD Hex Editor I should see the Amiga Sync
Markers for the beginning of each Amiga Secotor.

I know this has all been done before! Yes, I am going
to re-invent the wheel by writing my own DiskReader!
Rob Smith invented the DrawBridge hardware & it is
working great! I'm writing AROS software to use it to
read Amiga Disks. When I hopefully reach that goal
then AROS will have surely come a long way from its
roots in the Amiga 68k days till the present. It will be
a first for AROS to be able to finally read Amiga Disks!

I hope it all works as expected. :-)

Here are some words of encouragement from Rob Smith from his blog about DrawBridge.

"When I started this project I hadn’t got a clue how the floppy drive worked,
and even less how the data was encoded onto them."

https://amiga.rob...uk/history

The results for reading the drive rpm in TeraTerm can be seen in the screenshot.

Notice that I'm using Notepad to write the single byte commands then copy/paste in
the TeraTerm Window. I will explain what each character command does.

After sending each command the Arduino will respond with a ' 1 ' that it received it.
The first command is ' + ' turn on the drive motor and spin the disk (Amiga disk must be inserted in drive).

The first ' 1' means command received - the activity light comes on the DrawBridge Floppy Drive &
the drive starts to spin.

The second command is ' P ' which requests that the Arduino perform the Drive RPM Test while the
disk is spinning. It replies ' 1 ' followed by ' 300.75 ' which is the drive rpm calculation based on the
sync pulses received for about 5 rotations. The Amiga DD Disk spins at about 300 rpm which is
about 5 rps (rotations per second). It takes almost a full second, which is a long time in computer time,
for the results to appear in the TeraTerm Window. After the data is received it's ok to turn of the drive motor.

The last command is ' - ' because gotta turn off the drive motor or it will keep spinning...

The Arduino replied with a ' 1 ' and the disk activity light goes off and the drive spins down to a stop.

That's the sequence to measure the drive rpm using Arduino commands for the DrawBridge Device.

Currently the SerialDiskReader can turn on the drive motor, request the drive rpm & turn off the drive.
It's almost working. It's important to be able for the DiskReader to turn on/off the disk motor. That's
because most of the main functionality such as seeking a track, reading a track, etc require that the
disk is spinning. So, we are almost there!