OqtaDrive

[Derek_Stewart]

Hi

I had 10 Oqtadrive v1.2b PCBs made, but there does seem to be a case for the single LED version.

There is a case for the v1.1 Oqtadrive PCB which has 2 LEDs, do I have got dome v1.1 PCBs made, awaiting delivery.

I will get the Case 3D Printed and see if I can make them.

There seems to be a QL internal PCB in development, which would replace a microdrive, and with QL-SD makes a good combination.

[Popopo]

Hi

I had 10 Oqtadrive v1.2b PCBs made, but there does seem to be a case for the single LED version.

There is a case for the v1.1 Oqtadrive PCB which has 2 LEDs, do I have got dome v1.1 PCBs made, awaiting delivery.

I will get the Case 3D Printed and see if I can make them.

There seems to be a QL internal PCB in development, which would replace a microdrive, and with QL-SD makes a good combination.

Hi derek,
there are some STL for the version with 2 LEDs, in fact I have one and in the forum that already you know you could see some pictures how it looks and fit.

[Derek_Stewart]

Hi Popopo,

Ues that is one I meant , thete is supposed to be a design for the 1.2b PCB with the single LED.

So I will make the v1.1 PCB with 2 LEDs, I downloaded the Rapberry Pi SD Card Image file, is it okay to use this?

[Bloodnok]

An update regarding the h/w drive shadowing. An initial implementation in OqtaDrive is working fairly well now. At least with the Spectrum. I haven't tested with my QL yet. A couple of CATs is usually enough to get a full, error free copy of the cartridge.

Hi Alex,

I've been done this rabbit hole before (around 2017 from my notes). I was planning to release a clone function as a firmware update for the vDrive ZX but did not achieve the performance required to be useful in a commercial product.

A few things I found:

1. Reading from the same drive that the cartridge was formatted on always gave good results. This is due to the speed of the playback and the azimuth of the recording being the same which leads to the data channels being time coincident, at the correct data rate, and at a high signal level. Over time the performance dropped off even with initially good recordings mainly due to tape wear.
2. For cartridges from other sources, and on other drives (I have about 10 drives to test on), the results were poor. Due to different tape head azimuth, the data channels have a timing difference and due to recording speed differences, the data rate is not standard. As the biphase decoder needs to extract the clock from the data to correctly determine the cell boundaries, and not rely on a fixed period value, then performance drops off quickly with deviations in data frequency. Short term changes in speed due to the basic(cheap) tape mechanism employed don't make things any easier.
3. I believe the Sinclair ULA overcomes this by using a PLL to lock the decode clock with the incoming data frequency as is standard with biphase decoders (floppy disk drive controllers etc. have them). The vLA1, an IF1 replacement ULA that I reverse engineered when working on the vDrive ZX, has a digital form of a basic PLL to lock the decode clock for each channel and works well. There are certainly micros available these days (e.g. STM32F7xx) that have the resources to implement a PLL - and FPGAs of course. The ATMega328P used in the vDrive ZX (and Oqtadrive) is simply too slow and lacking suitable resources to be effective.

As the Oqtadrive samples both channels at once then I expect you will get similar results to what I did and find that the decoder will not be able to handle real world data streams effectively. I've since moved to a different path to solve the archiving problem, as the vDriveZX/QL, working as a Microdrive hardware emulator, does all it needs to (the original Microdrive only had to play and record - not decode messy signals).

Hopefully you find this info useful and maybe save you some time.

Cheers,

Charlie

[alvaroalea]

Hi Popopo,

Ues that is one I meant , thete is supposed to be a design for the 1.2b PCB with the single LED.

So I will make the v1.1 PCB with 2 LEDs, I downloaded the Rapberry Pi SD Card Image file, is it okay to use this?

Hi, I think I'm the creator of the SD image you refer, yes, in fact this image has only be tested with the PCB that have 2 led.
In any case I don't think that using other PCB shall be a problem.

Enviado desde mi Mi MIX 2S mediante Tapatalk

[Derek_Stewart]

Hi Popopo,

Ues that is one I meant , thete is supposed to be a design for the 1.2b PCB with the single LED.

So I will make the v1.1 PCB with 2 LEDs, I downloaded the Rapberry Pi SD Card Image file, is it okay to use this?

Hi, I think I'm the creator of the SD image you refer, yes, in fact this image has only be tested with the PCB that have 2 led.
In any case I don't think that using other PCB shall be a problem.

Enviado desde mi Mi MIX 2S mediante Tapatalk

Hi alvaroalea,

I read all the Oqtadrive thread on va-de-retro.com and tried to register as a user, but could not to seek permission to use the SD Card image.

I have converted the instructions to English, as my Spanish is only good for ordering Wine and Beer...

[Popopo]

I've put an OqtaDrive inside my Issue 5 QL, using Tom Dalby's μPCB 1.0, with minor modifications. Due to the tight space, I had to shave off one corner. Note that a prerequisite for this build though is to replace the original 5V linear power regulator and its massive heat sink with a small bucket converter, to free up enough space.

I wanted to put OqtaDrive inside the QL because an external adapter can only act as drives 3 through 8, but I wanted to take advantage of OqtaDrive's hardware drive mapping also on my QL. The adapter still hooks up to the Microdrive port, except for the COMM signal which is directly taken from the PCB connector of internal drive 1 (pin 1). Drive 1 then gets COMM from COMM_OUT of the OqtaDrive adapter, i.e. the OqtaDrive adapter is now first in chain. This way I can freely move the internal drives, or completely disable them.

Full disclosure: I'm the author of OqtaDrive

How works this LM to power up the microdrives?
I was thinking about to do the same, but just lazy about to check which one would be less noisy or work better than others step-down.

[Popopo]

I have converted the instructions to English, as my Spanish is only good for ordering Wine and Beer...

Hi Derek,
Alvaro already answered you, about the translation, Google Translator does it fine enough, but if you have any trouble I will help you with any translation.

About the case, I have both, the original one that I bought in a Retroradionics (a replica) and the printed cases for 2 leds, keep in mind...LEDs get too down, so not to solder them close to the board, size them firstly before soldering...
I cannot show a photo now, pay attempt-ion on the pictures from the VaDeRetro forum.

[aalea]

Hi, I think I'm the creator of the SD image you refer, yes, in fact this image has only be tested with the PCB that have 2 led.
In any case I don't think that using other PCB shall be a problem.

I read all the Oqtadrive thread on va-de-retro.com and tried to register as a user, but could not to seek permission to use the SD Card image.

I have converted the instructions to English, as my Spanish is only good for ordering Wine and Beer...

SD image is on a mega link, you should not need any permission to download it, if you continue to have problems, tell me and I upload to other place.

https://mega.nz/folder/pEw1GKrY#hOOKJEAZ5YhjhZrtvCxErg

If you send me the instruction in english I will upload to the same place so everybody can use.

[Derek_Stewart]

I have converted the instructions to English, as my Spanish is only good for ordering Wine and Beer...

Hi Derek,
Alvaro already answered you, about the translation, Google Translator does it fine enough, but if you have any trouble I will help you with any translation.

About the case, I have both, the original one that I bought in a Retroradionics (a replica) and the printed cases for 2 leds, keep in mind...LEDs get too down, so not to solder them close to the board, size them firstly before solderin...
I cannot show a photo now, pay attempt-ion on the pictures from the VaDeRetro forum.

Hi Popopo,


Thank you for the information on the fitting of the LEDs, I will bear this in mind in construction of the v1.1 Case and PCB.

Since there is no case for the v1.2b PCB yet, I might alter the v1.1 case to only have 1 LED.