Sunday, 23 August 2020

SD2IEC power options

Back in the mists of time, The Future Was 8 bit started by selling SD2IECs. They had one power option, the datasette port.

That was nice and simple, you plugged the IEC connector into the IEC port and the power connector into the datasette port and away you went. "But what if I want to use the datasette port as well?" came the call, so a version was produced. That again was nice and simple, plug in the IEC connector for data, and the userport connector for power.

"But what if I also want to use the userport", "what if I have a C16", "I want to use a disk drive as well", and so on. Various options were created, with different connector, some with multiple connectors etc. Those are being phased out, and replaced with various adapters. In order to best describe the options available, here are some pictures. Find one that looks like the configuration you want and order that. 


Be warned, the following pictures are upside down. They have been taken by a trained professional with adequate safety gear in place to make sure all the electrons do not fall out. Do not try this at home unless you are confident to undertake such a task. 

Also note the word 'TOP' is written in large, friendly letters on the top of the blue connectors, make sure the connector is inserted this way around.

VIC 20 / Commodore 64

The options for the C64 and the VIC20 are essentially the same, as they have the same datasette port and userport on the back. The main difference is the VIC20 should have the essential VIC20 Penultimate+ Cartridge installed.

Whereas the C64 should have an Epyx Fastload Reloaded.

Option 1: Userport Powered

This is a good option if you plan to use a datasette drive at the same time, and have no plans to make use of the userport. If in doubt, I would probably go for this one.

Option 2: Datasette powered.

This is the classic configuration, and a good option to pick if you don't have a datasette drive, or don't plan to use one at the same time as the SD2IEC, or if you have some userport peripherals or may want to use some at some point in the future.

Option 3: Userport Power Adapter

The datasette power adapter allows you to use a datasette powered SD2IEC from the userport. Useful if you can't decide on the above two options, you can insert the adapter if you need to use a datasette drive, but the rest of the time, you can remove the adapter and plug the SD2IEC power cable directly into the datasette edge connector as normal.

Option 4: Userport saver

This option is for the people who want to use both a datasette and some userport peripherals at the same time as the SD2IEC (or just like the LED voltmeter and reset button it provides).

Option 5: Datasette Power Extension

This extends the datasette power cable so that you can use a real 1541 disk drive as well as the SD2IEC, and still have it powered by the computer.

Option 6: Userport Power Adapter

This option is also for use with a real disk drive, but gets it's power from the userport to power a datasette powered SD2IEC.

Commodore plus/4

Option 1: Userport power

The plus/4 still has a userport, but the datasette port is different. So again here, the recommended option is the userport.

Option 2: Userport Power Adapter

You can also use the userport power adapter to connect a normal datasette powered SD2IEC to a plus/4.

Option 3: Userport saver

Or you could use the userport save if you need access to the userport and mini DIN datasette port.

Option 4: Mini DIN Datasette Power Adapter

An alternative for the plus/4 is to use a power adapter from the mini DIN datasette connector to a datasette powered drive. (note these adapters only pass through 5V power, these cannot be used to connect a standard datasette drive to a plus/4).

Commodore 16

The Commodore 16 does not have a userport, so the mini DIN datasette adapter is the only option here.

Commodore SX-64

The SX-64 does not have any type of datasette port, so userport powered is your best option (or using the userport power adapter or userport saver, those options are not shown).

Commodore 128

The datasette port on the C128 is either too far away or has too small a cutout to allow the connector to inserted (depending on the model). So again the Userport powered SD2IEC is recommended (or one of the adapters - a prototype userport save shown, production models are white with a 5V power meter, as shown in previous photos).

Case colours

The range of SD2IEC drives can be seen on The Future Was 8 bit, the only choice you have left to make is which colour SD2IEC do you want, they are all the same inside, but there are various case colours to better match your computers.

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Sunday, 2 August 2020

Minstrel Updates

Updated versions of the Minstrel 2, 3 and 4th are now available from The Future Was 8 bit.
I have simplified the options down to a single version for each, with optional ZXpand for the Minstrel 2 and 3.
These are now single boards, with the keyboard integrated into the main board. The is a keyboard overlay PCB with keywords as appropriate for the system, and the optional ZXpand board which is soldered onto the edge connector.
Now in fancy new packaging. If we call it a collectors edition, does that mean people will try to buy all of them?

Minstrel 2

This is a kit to create your own ZX80. The design follows closely the original ZX80 schematic, with a few improvements to make it more useful, 16K of RAM, multiple ROM images (4K or 8K versions of BASIC), and a modified composite video output circuit to make up for the shortfalls in the original design.
As with all of these Minstrels, these are self assembly kits, with all modern, still in production, through hole components.
The only surface mount part is the SD card socket on the ZXpand, and this is supplied pre-soldered so you don't need to do that if you want the ZXpand option. This allows you to load programs direct from SD card, and also adds a joystick port which supports ZXpand, INKEY$ and Kempston modes.

Minstrel 3

The Minstrel 3 is ZX81 compatible, it implements the same functionality as the ZX81, but with a different circuit designed with modern 74HC chips, rather than relying on an original ULA.
The updated design includes the NMI slow/fast mode used by lots of ZX81 games, and 32K of RAM with support for many of the high resolution techniques for the ZX81.
There is also a version of the Minstrel ZXpand for the Minstrel 3, again with a pre-soldered SD card socket, for fast SD card loading and the multifunction joystick port.

Minstrel 4th

The Minstrel 4th is a Z80 single board computer, which implements a memory map and display compatible with the Jupiter Ace, so it can run Jupiter Ace software, and you can try out the Forth language.

The Minstrel 4th is 'designed for RC2014' and can be expanded via an RC2014 bus connector, to make use of all sorts of existing expansion cards.

All of those kits are available now from the new 'Tynemouth Software DIY Computer kits' section of The Future Was 8 bit -
Along with the Mini PET of course.

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Sunday, 19 July 2020

Mini PET Update

The Mini PET seems to have been received well. I am seeing lots of pictures of very neatly assembled boards (and also the one that TFW8b built) and revived PETs up and running again.
That's great to see, and very few problems building them, other than a few people who had to built it without reference to the manual (the person packing the orders has of course been fired). So far, the only issue to report is a slight error that seems to have slipped though all of our other testers (who have, of course, all now been fired).
When first putting together the design for the prototypes of the Mini PET, I came to the userport and was pleased to find I had already drawn a component for the PET userport. Perfect I thought and added it to the design. I didn't consider at the time that I had drawn that component for things which plug into the userport on a PET, not for the host side of the PET userport, which is the mirror of that pinout. (I have, of course, also been fired)
And so, the pinout is reversed. Pins that should be 1,2,3,4... are 12,11,10,9... During testing, no one it seems noticed that, as no one it seems has anything that would plug into the PET userport. The only things I had were userport sounders and composite video output. All of which were already provided on the Mini PET. I think this will only affect a handful of people making userport serial interfaces, as the PET seems to have hardly any commercial userport peripherals.
I have made some boards which reverse the pinout. An interesting routing problem, 12 wires what all need to cross over each other and the same on the other side of the board.
I'm fairly happy with the solution I came up with, although I wonder if there is a neater way to reverse the connections? Those are being sent out to anyone with an affected board (V1.42, V1.44), although no one has actually asked for one, and only one user has reported a problem. The ones going out have white soldermask.
I build a little LED tester plug to make sure that was working correctly.
Because of the userport problem, I have moved more quickly than planned to the next board designs, as correcting the pinout on the userport required quite a bit of rerouting. The updated versions of the 'Kit A' boards is V1.45.
Other than the correction to the userport pinout, and a couple of minor tweaks, this is pretty much the same as before.
The LED tester confirms the pinout on these boards is now correct, so the twister boards are not required for V1.45 and later boards. The new 'kit A' versions (for use stand alone with a keyboard) are shipping now.
The Mini PET boards had been designed to be the same size as the keyboard PCB, which had already been designed as a direct replacement for the chiclet keyboard on the 2001 PET, so the Mini PET was designed to be the same width as that.
That meant it wasn't quite wide enough to pick up on the two mounting pillars at the back of the PET case.
I had tried out a green soldermask version of the Mini PET board and that had looked better inside the PET case. It seemed a good opportunity to split this into two versions, one white soldermask board, the same size as the keyboard, for stand alone use, Kit A. The second, a green soldermask board which fits inside the PET, kit B.
The first thing to do was to make the B boards larger, so they are now the same width as the top end of the original PET boards.
So those now fit into the case and pick up on both rear mounting pillars.
It also seems a good idea to remove things not required for this version.
I've removed the DC jack, and boxed off the composite video section, which can be fitted if you need it, but otherwise can be left unpopulated.
You can see here I prefer to fit the smaller logic chips without sockets. They are still supplied in the kits if you want to use them, I just think it looks better without. TI uses the same moulding for 14 and 16 pin chips, so when aligned correctly, you don't see the difference between 14 pin and 16 pin chips.
The wider kit B boards now pick up on both rear mounting pillars, and the power supply interface board has been integrated to make a single board solution.
As before, this can be used with the 9 way power connector found in most PETs or the 5 way connector from the original 2001s. You could cut down the pin header before soldering if you are only going to be using the 5 pin connector. But it's not a problem if you don't, one missing pin is an extra ground, the other two are for a second transformer winding which is not used.  
There is now a side datasette port, for datasette 2, positioned as on later PETs, so the board gives access to both rear and side datasette ports.
This now works better for the 8032-SK case where the board is mounted at 90 degrees, and the side port becomes the rear port.
The board picks up on the same two mounting points and the extension cables connect as normal inside the 8032-SK case.
The board can alternatively be mounted further into the PET case, which allows an SD2PET to be installed inside the case. This can be useful in unattended events to keep it away from prying hands, or for those short of desk space, or wanting to access the SD card by lifting the case rather than reaching around the back.
The second datasette is still accessible through the holes in the case in this configuration.
You will see I have moved over to using jumper settings, rather than DIP switches on the B boards (thinking it would be adjusted less frequently once mounted inside a PET case). 
I'm not sure about this, and may go to a single 8 way DIP switch on future boards as it adds quite a few extra parts to be sorted out and soldered in, but keep the onboard labelling of options.
These kits are being distributed by The Future Was 8 bit. My Tindie store remains closed due to the ongoing problems with shipping. 

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