Wednesday 15 July 2015

New PET microSD boards

This is an old post, preserved for reference.
The products and services mentioned within are no longer available.

This post has been left for historic information. The PET microSD is no longer in production. The replacement SD2PET is available now, more information on the pre-order page.

The latest batch of PET microSD boards are ready, and they have changed a bit, they've gone blue!
There are also a few other minor mods, most notably the package of the 74LVC125A buffer has been changed to give more room around the other components. The power LED is also now blue to match, with green for activity, red for error.
To go with this, there is now a board which taps the power from the datasette connector, and now includes a pass through to allow the datasette to be used at the same time.
I said there was a lot going on in the world of IEEE-488 drive replacements, here is a selection of them. The first two boards on the back row are ATmega328P based boards. At the left is the first prototype, and in the centre, a new version with a better microSD interface, the same as the PET microSD.
Both of these are meant as low cost drives. They do have a full microSD card interface, with voltage regulator and levels shifters, but they lack IEEE-488 bus drivers, so shouldn't really be used with other IEEE-488 devices. The smaller processor somewhat limits functionality, so there is no disk image support. These can run petdisk firmware or my own custom firmware, which is still in development.
The rest are ATmega1284P based boards. These all run Nils Eilers NODISKEMU firmware. The right most on the back row is the prototype pet microSD - I tend to use green connectors on the prototypes, so I can tell them apart. On the front row at the left with the large LCD display is the petSD+, available from Dave Stevenson. Here it is without the display:
Although it may not look it, hardware wise, it's very similar to the PET microSD, the same chips just with smaller packages. Where it differs is the full size IEEE-488 / GPIB connector, the same used on Commodore's disk drivers. There is also a battery backed real time clock on board, so files are written with the correct date and time, and this can be used by software running on the pet. It is designed to be used with the display and buttons, although this is yet to be implemented.
The final board in the family group is the new pet microSD.
Here shown plugged into a 4032, with the passthrough connector used to connect a datasette.
And here testing a 3032 board, it's quite useful for this as it lays flat on the bench.
The pet microSD is available for £50 + postage, and includes the datasette power board and a microSD card with a selection of software. There are various other options including one that can mount internally in a 8032-SK or 8096-SK.

2022 Update: I have since designed a much nicer SD drive for a PET. The SD2PET is available from  The Future Was 8 bit