Gotek with the HxC on an HP1652B

[siredward]

I first tried the factory Gotek firmware but could not get it to work. My situation is that I have both a floppy drive and Gotek hooked up to an HP 1652B Logic Analyzer. I am able to enable the floppy and boot the analyzer normally. My plan was then to format the Gotek and copy over the system disk to the Gotek by enabling one drive at a time (manually). I was able to start a format with the factory code, but it does not complete.

So I decided to try this with the HxC firmware and have that loaded into the Gotek. Per what I found on the web, the drive is run as follows:
DD double density, 2 sides, 80 tracks per side, 160 total , 5 sectors per track, 1024 bytes/sector 500 kbit/sec, 600 rpm,
GAP3 = 44, Interleave 1:1, first sector ID 1, Skews: 0.
I used the 'custom firmware' feature and looks like I have it successfully loaded (showing my prompt on the 7-segment LED display). Now I need to prepare the USB disk and that is where I am stuck. I have formatted the USB in FAT32 and copied over the CFG file for indexed mode. But I am confused on all the options to prepare the disk image. All the partitioned USB images show 300rpm, so that does not match.

I would really appreciate some assistance on this. Been working for several weeks to not look like a total noob, but now I am stuck.

[siredward]

An update. Getting closer but still no joy.

I discovered the 'd' menu in the 7-segment menu, which does a format. Format succeeds and the USB now looks like a 720kB disk on my PC. I tried the format on my Logic Analyzer and it completes it. But doing a directory of the disk shows "Disk not supported". I tried all 7 combinations of Jumpers JA, JB, JC with no change. J5 only causes the disk light to come on and stay lit.

I hope someone can throw me a lifeline. I see the HP1652B in the list of completed projects and would love to speak with that person.

[Jeff]

Hello,

Sorry for the delay. I will package the information i got so far.

[Jeff]

An update. Getting closer but still no joy.

I discovered the 'd' menu in the 7-segment menu, which does a format. Format succeeds and the USB now looks like a 720kB disk on my PC. I tried the format on my Logic Analyzer and it completes it. But doing a directory of the disk shows "Disk not supported". I tried all 7 combinations of Jumpers JA, JB, JC with no change. J5 only causes the disk light to come on and stay lit.

I hope someone can throw me a lifeline. I see the HP1652B in the list of completed projects and would love to speak with that person.

I compiled the instructions and files in this archive :

https://hxc2001.com/download/floppy_dri ... P_1652B.7z

Code: Select all

-------------------------------------------------------------------------------
-----------H----H--X----X-----CCCCC-----22222----0000-----0000-----11----------
----------H----H----X-X-----C--------------2---0----0---0----0---1-1-----------
---------HHHHHH-----X------C----------22222---0----0---0----0-----1------------
--------H----H----X--X----C----------2-------0----0---0----0-----1-------------
-------H----H---X-----X---CCCCC-----22222----0000-----0000----11111------------
-------------------------------------------------------------------------------
-- Contact: hxc2001<at>hxc2001.com --------------------- https://hxc2001.com --
-------------------------------------------------------------------------------
HxC Floppy Emulator project
(c) 2006-2024 Jean-François DEL NERO / (c) HxC2001
Forum    : https://hxc2001.com/floppy/forum
Facebook : https://www.facebook.com/groups/hxc2001
-------------------------------------------------------------------------------

-------------------------------------------------------------------------------
                     HP 1652B HxC Floppy Emulators package
-------------------------------------------------------------------------------

-------------------------------------------------------------------------------
Original floppy drive and disk technicals informations
-------------------------------------------------------------------------------

Original drive : Sony MP-F52W-30
-------------------------------------------------------------------------------

3"1/2 600 RPM Shugart type drive with an disk change reset line on pin 1.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>>>>>>>>> Warning: +5V and +12V Power supply in the floppy ribbon! <<<<<<<<<<<
>>>>>>>>>>>>>>>>> !Floppy ribbon Modification needed! <<<<<<<<<<<<<<<<<<<<<<<<
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

DD capacity at HD rate (500kbits/s)

Note about the "DISK CHANGE" signal (pin) :

This line is true (low) whenever a disk is removed from the selected drive.
The line will remain true (low) until both the following conditions have been
met:

a. A disk is inserted,

and

b. A STEP pulse or DISK CHANGE RESET signal (pin 1) has been received when
the drive is selected.

Full drive datasheet :

https://hxc2001.com/download/datasheet/floppy/thirdparty/Sony/9-975-174-01_MP-F52W_Product_Specifications_Sep85.pdf

Disk format
-------------------------------------------------------------------------------

Tracks : 80
Sides/heads : 2
Sectors per track : 5
Sectors size : 1024 bytes

Raw capacity : 80 * 2 * 5 * 1024 = 819200 bytes.

Note : The last track sector id start at 97. (97, 98, 99, 100, 101)

-------------------------------------------------------------------------------
HxC Floppy Emulator wiring and settings :

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>>>>>>>>> Warning: +5V and +12V Power supply in the floppy ribbon! <<<<<<<<<<<
>>>>>>>>>>>>>>>>> !Floppy ribbon Modification needed! <<<<<<<<<<<<<<<<<<<<<<<<
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Please check the file HP165X_HxC_Floppy_Emulator_Connection.png for the correct
wiring.

A simple way to accomplish this is to take a standard floppy ribbon and
cut the wires that need to be disconnected and redirect the +5v wires from
the HP 1652 to the +5v floppy emulator power supply input.

-------------------------------------------------------------------------------

The HFE images must be at 500kbits.

Interface mode : Custom - Pin 2 "nDiskChange 1" - Pin 34 "nReady"

(Note "nDiskChange 1" means : clear disk change signal after a head step)

Set the "Drive B input as Drives Motor On" option.
Disable "2 drives emulation"

Jumper/Switch settings: Set ID0A and ID3B to ON.
(all others switch need to be turned to OFF)

-------------------------------------------------------------------------------
Gotek specific additionnal instructions
-------------------------------------------------------------------------------
If you use a Gotek with the HxC firmware here is some more things to do

Go to this page :
https://hxc2001.com/custom_fw/

Set :
- Non gated mode
- "Floppy Interface mode" to "Advanced pins configuration"
- "Advanced pin 2 configuration" to "nDiskChanged (mode 1 : DSKCHG Clear -> Step only)"
- "Advanced pin 34 configuration" to "nReady"
- Enable Reset DC (Diskchange) input signal (pin PA14)
- Bitrate override : "500kbit/s"

Then go down to "Build order" to generate the new firmware.
Once upd file received by email, you can update your gotek with this firmware.
Update procedure :
https://hxc2001.com/docs/gotek-floppy-emulator-hxc-firmware/pages/firmware-update.html

On the Gotek put a jumper to "MO" and remove any other jumper!

The reset diskchange signal at pin/wire 1 at the machine and pin/wire 4 at
the gotek according to the "HP165Xx_HxC_Floppy_Emulator_Connection.png"
wiring instructions need to be routed to the JTCK-SWCLK/PA14 signal.
See "gotek_jumper_and_dc_reset.jpg" to see how to add the connection.
-------------------------------------------------------------------------------

-------------------------------------------------------------------------------
Note : The HXCSDFE.CFG configuration file and file images present in this
archive already have the right settings! Just copy them to the SD Card!
-------------------------------------------------------------------------------

[siredward]

Wow thank you so much! I have downloaded it and will dive into this during the weekend.

Edward Cheung

[siredward]

Success! As instructed I generated a custom firmware with the options indicated. I flashed this successfully onto the Gotek. I then modified my cable to route Gotek pin 4 to LA pin 1 (also per instructions). I used a 4GB memory stick and copied onto it the HFE and CFG files that you sent me. Upon power up, the Logic Analyzer shows "No System disk", but when I hit "Select" to boot again, boot up completes successfully!

Now I want to have multiple disk images. As a guess, I replicated DSKA0000.HFE and named them DSKA0001.HFE and DSKA0002.HFE. Once I powered up I can use the Gotek buttons to select 000, 001, or 002. Boot up occurs fine on any of them, but when I do disk operations after changing from 000 to 001, it shows "No Disk". I cannot get it to read any images, even the original boot disk. What can I do to remedy this?

I truly appreciate the great help you have given me. NO WAY I would have figured this out on my own. Thank you.

[siredward]

Additional info

LA.jpg (83.25 KiB) Viewed 2946 times

In the attachment you can see the progress of the power up. Upon first power up, Disk Test does not pass (beep). You can see the DCHGE is low this entire time (indicating no disk), but it looks like a DRST is sent from the LA after this failure and prompts the Gotek to toggle DCHGE. I then hit "Select" to retry the disk and it boots completely. Then I navigate to the Disk Menu and I can see a directory listing. But when I press the Gotek front panel button to change disk image, and then try a Directory read, it shows "No Disk", and DCHGE is low all the time. Per the manual, this tells the LA that there is no disk. This line will go high once a disk inserted AND a STEP pulse is received.

For comparison here is a standard floppy:

LA2.JPG (55.1 KiB) Viewed 2943 times

So this definitely looks like a DCHGE issue. LA thinks no disk is inserted. Seems to me that the solution is to have the Disk Change line be high except when the front panel buttons are pushed.

[Jeff]

LA.jpg

That's a good start

i don't see the machine trying to clear the disk change : no "reset disk change" nor track step. Maybe its done later ?

Anyway : Which floppy emulator are you using ? (Which MCU is present on the board ?)

[siredward]

The MCU on my board is the AT32F415. The Gotek was purchased via Amazon.

On the disk reset signal, I can see short pulses on it (DRST) every time I press a front panel button on the Logic Analyzer. The waveform images I attached are from a newer Logic Analyzer (not the HP1652B), and I am not very familiar with using it. I do see transitions on DSRT, but perhaps the pulses are too short for the Gotek to see them. Based on this idea, I will try something tomorrow. Instead of using a jumper as you instructed to connect MCU pin PA14 to connector pin 4, I will use a resistor. This way I can manually short the MCU side to ground briefly to see if this causes HxC to raise DCHGE.

[Jeff]

The MCU on my board is the AT32F415. The Gotek was purchased via Amazon.

QFN32 version ?

[siredward]

Yes correct.

IMG_5567.JPEG (25.34 KiB) Viewed 2855 times

[siredward]

My idea did not work. Connected 51k from pin 1 (DRST) to PA14. Then after changing disk numbers on the Gotek, DRST is high, I momentarily grounded the PA14 side of the resistor. DCHGE does not change state and stays low. I am pretty sure that if it went high, the LA would do a read of the disk.

[Jeff]

My idea did not work. Connected 51k from pin 1 (DRST) to PA14. Then after changing disk numbers on the Gotek, DRST is high, I momentarily grounded the PA14 side of the resistor. DCHGE does not change state and stays low. I am pretty sure that if it went high, the LA would do a read of the disk.

Let me check if the QFN32 Gotek support the reset dkg signal.

[siredward]

Ok, that is appreciated.

FYI, this is what Sid added to his version:

floppy emulator schematic 747x396.jpg (59.11 KiB) Viewed 2774 times

Looks like it goes low when either switch is pushed on the Gotek and goes high when the correct pulse is received.

Image from here: https://stonemarmot.com/rantrave/gotek.html

[Jeff]

Ok, that is appreciated.

FYI, this is what Sid added to his version:

floppy emulator schematic 747x396.jpg

Looks like it goes low when either switch is pushed on the Gotek and goes high when the correct pulse is received.

Image from here: https://stonemarmot.com/rantrave/gotek.html

... Back from holidays...

This shouldn't be needed as long as the software is managing this.

I just checked the reset disk change signal on the qfn32 gotek and there is one issue : on the qfn32 gotek this signal is in conflict with another floppy signal, so no surprise if this currently doesn't work. i think i will apply the same workaround as with the apple ii firmware variant : use the rotary push button rotary input as reset signal. you will have to disconnect or not push this button, but this is not a major issue.

EDIT : Before i do the modification can you try to just disconnect the reset diskchange signal jumper and regenerate the firmware with these options :

Go to this page :
https://hxc2001.com/custom_fw/

Set :
- Non gated mode
- "Floppy Interface mode" to "Advanced pins configuration"
- "Advanced pin 2 configuration" to "nDiskChanged (mode 1 : DSKCHG Clear -> Step only)"
- "Advanced pin 34 configuration" to "nReady"
- Bitrate override : "500kbit/s"

(Enable Reset DC (Diskchange) input signal (pin PA14) NOT set ! )