exxos's Atari, Amiga & retro forum

@rubber_jonnie Hoping to see a write-up about the various Beeb add-ons in the near future...if only to help me choose which ones to shortlist for my two model B Beebs...then I can look at the wider options for the Master I've committed to buying (facepalm)

No idea how I am going to explain that one to my better half...so it might just have to be 'discovered' while sorting out the garage one day :D :lol: :roll:

JezC wrote: 03 Jun 2021 09:28 @rubber_jonnie Hoping to see a write-up about the various Beeb add-ons in the near future...if only to help me choose which ones to shortlist for my two model B Beebs...then I can look at the wider options for the Master I've committed to buying (facepalm)

No idea how I am going to explain that one to my better half...so it might just have to be 'discovered' while sorting out the garage one day :D :lol: :roll:

Uh oh, somebody's gonna be in trouble.....

Already bought another TurboSPI, so will likely do a write up on that first.

I will probably also look at a write up for Mr Morleys 64KB EEPROM and also the bus sniffer I got from him once built. They are a tiny mmc adapter that plugs into the user port and a ROM, but gives a nice easy disk interface.

I will also do a bit of a refurb on the dual analog joysticks, and I might also do a write up on the tool situation, and just what you can do with basics, and some of the pitfalls.

@JezC I don't want you getting in to trouble now. I'm happy keeping the Master till you can find it a hiding place :lol:

rubber_jonnie wrote: 02 Jun 2021 23:27 Trouble is, I'm running out of machines to fix! IIRC my last 2 broken machines are a Spectrum and my Mac Classic. Both are in storage, so they will be on the list once I get into my new workshop.

I've found that I enjoy repairs almost as much if not better than actually using the working machines. I'm planning some car booting to keep my fix inbound.

BennehBoy wrote: 03 Jun 2021 10:36

rubber_jonnie wrote: 02 Jun 2021 23:27 Trouble is, I'm running out of machines to fix! IIRC my last 2 broken machines are a Spectrum and my Mac Classic. Both are in storage, so they will be on the list once I get into my new workshop.

I've found that I enjoy repairs almost as much if not better than actually using the working machines. I'm planning some car booting to keep my fix inbound.

I'm very much the same, though I think the Mac Classic is going to take some fixing even with all the help I've had so far!! I really enjoyed fixing this one, it was a real challenge.

Still figuring out how I can use the ROMs you sent as I need to adapt them slightly before they'll work. Somebody off stardot did send me a diag ROM as well, which worked out of the box, so I think I just need to do a little digging to get that sorted, then I'll be able to try them.

Something to do with pin A13 and possibly another. They will get tested though!!

Are these larger than 16Kx8 EPROMs then?

When I use 28C256 EEPROMs in the BBC I merely load the data into the upper half (starting at 0x4000) as the top address line will always be held high.

stephen_usher wrote: 03 Jun 2021 12:09 Are these larger than 16Kx8 EPROMs then?

When I use 28C256 EEPROMs in the BBC I merely load the data into the upper half (starting at 0x4000) as the top address line will always be held high.

The ROMs I have are 27C256, which are also 32Kx8, however the pinout is slightly different to 28C256's.

In terms of blank ROMs, what would you recommend? Compared to the original Hitachi mask ROMs, the pinouts are very similar, but do need some adaptation from what I can see. Or am I missing a trick here?

Do you not just need the adapter if you want to be able to switch the banks? I suppose it depends on whether pin 27 is grounded or high - if it's floating it would flip banks arbitrarily, and I think I only wrote the images to the upper bank 0x4000...

BennehBoy wrote: 03 Jun 2021 14:27 Do you not just need the adapter if you want to be able to switch the banks? I suppose it depends on whether pin 27 is grounded or high - if it's floating it would flip banks arbitrarily, and I think I only wrote the images to the upper bank 0x4000...

I'm going to print out the mask ROM and 27C256 pinouts next to each other, then go for a trawl through stardot to see if I can find any more info. I know there is an adapter available (I think on BooBip), but let's see where I can go with this first.

@rubber_jonnie From some very dim & distant memories I'm sure we just used 2764 & 27128 EPROMs to hold 8k & 16k ROM images...and I was pretty sure that applied to the internal sockets, not just the different sideways ROM solutions around in the mid-80s....

I may even have some lying around somewhere, so let me know if you want some in the future.

As for being in trouble, I've temporarily distracted her by showing her some lovely guitars...and they are much more expensive than that Master!

@PhilC we've been told that we are getting an annual pay rise, so I just need to see what I can spare/how much overtime I can do to expedite payment... :D