Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

for bbc micro/electron hardware, peripherals & programming issues (NOT emulators!)
User avatar
daveejhitchins
Posts: 5053
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham
Contact:

Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by daveejhitchins » Tue Sep 04, 2018 10:35 pm

New ARA III - Advanced ROM Adaptor Mk III - This is a low cost writable ROM cartridge, for the Electron and Master, using a single 28C256 (EEPROM) and GAL16V8D with a PCB jumper for disabling/enabling write protection - a switch could be connected to this header.

When used with the Electron, JGH's New Plus 1 Support ROM Utilities work as listed in the User Guide. When used with the Master, MartinB's Utilities work just fine.

The board has been developed for Dave Moore (Arcadian) as a low cost Games Cartridge to be used at some of the shows he runs. As a result of trying to keep the costs down to an absolute minimum I'll be ordering more than Dave needs and I'll be making them available to everyone at just about cost price. You'll be able to order just a PCB (it will have gold plated edge connectors) or built PCB - both with a 3D printed case option.

The prototypes have one Mod. (see below for details) but work fine with the Mod. in place. They don't have gold plated fingers! I have 9 spare PCBs at £3.50 each which includes UK postage. I'll list the BOM and GAL file tomorrow. I can also provide a kit of parts or build them up if needed.
IMG_2845.jpg
The Mod. involves cutting some tracks above the GAL placed in a way that makes hem easy to cut! Why . . . I read the datasheet (it's been a long time since I read it fully!) and followed these instructions:
The GAL16V8 input and I/O pins have built-in active pull-ups. As a result, unused inputs and I/O's will float to a TTL "high" (logical "1"). Lattice Semiconductor recommends that all unused inputs and tri-stated I/O pins be connected to another active input, VCC, or Ground. Doing this will tend to improve noise immunity and reduce ICC for the device.
Don't, as it seems to screw-up the operation of the device!

I'll post the 'production' pricing as soon as it's available.

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

User avatar
MartinB
Posts: 5233
Joined: Mon Mar 31, 2008 9:04 pm
Location: Obscurity
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by MartinB » Tue Sep 04, 2018 10:52 pm

I’ll take one with a kit of parts Dave - let me know the price. Do my utilities also work with the cart in an Elk?

User avatar
Elminster
Posts: 3762
Joined: Wed Jun 20, 2012 8:09 am
Location: Essex, UK
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by Elminster » Tue Sep 04, 2018 11:28 pm

I might take a blank board from you, I seem to have space gals :)

Add to my collect of ARA 27c only and tweaked ABR SRAM, 27c or 28c. Means I could have one board with a eprom, one with SRAM and one with eeprom all at the same time. Not sure why I want to do that. So if over subscribe then happy to let someone more needy have it. Otherwise can collect one at Cambridge?
Last edited by Elminster on Tue Sep 04, 2018 11:31 pm, edited 1 time in total.

User avatar
tricky
Posts: 3672
Joined: Tue Jun 21, 2011 8:25 am
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by tricky » Wed Sep 05, 2018 6:40 am

I'll take two with parts (one if you have too many takers).

User avatar
daveejhitchins
Posts: 5053
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by daveejhitchins » Wed Sep 05, 2018 6:45 am

MartinB wrote:
Tue Sep 04, 2018 10:52 pm
I’ll take one with a kit of parts Dave - let me know the price. Do my utilities also work with the cart in an Elk?
Martin: See listing below for what you need . . .

Re Your utilities - yes they do work - I do have issues, though! When used with the Master or Electron I think you may be 'corrupting' some workspace, as I've found it mandatory to Ctrl/Brk (just a Brk wont do!) between commands. I'm still not sure about your use of the inbuilt Lock! - It seem as though no matter what I do I always have to unlock first - I've never used your EEP32 LOCK xx command! Can the Lock/Unlock command be integrated with EELOAD?

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

User avatar
daveejhitchins
Posts: 5053
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by daveejhitchins » Wed Sep 05, 2018 6:49 am

@Tricky and Elminster . . .

I'll bring boards and components to Cambridge . . .

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

User avatar
daveejhitchins
Posts: 5053
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by daveejhitchins » Wed Sep 05, 2018 7:44 am

ARA III BoM - (as at 05-09-18):

Code: Select all

PCB				£2.50
28C256				£1.63
GAL 16V8 (programmed)	        £1.05
28 pin IC socket (std)		£0.41
28 pin IC socket (LP)		£0.62 - Needed for 3D printed case
20 pin IC socket (std)		£0.32
20 pin IC socket (LP)		£1.00 - Needed for 3D printed case
Resistor (10K or 12K)		£0.02
2 x 100n Capacitor (X7R)	£0.20
Right angled header		£0.04
Jumper				£0.05
3D printed case			£3.16

Note: You don’t really need IC sockets!

P&P to UK at cost
Just let me know what you actually need!

Dave H :D

Edit: Cap price updated.
Last edited by daveejhitchins on Wed Sep 05, 2018 8:08 am, edited 1 time in total.
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

User avatar
daveejhitchins
Posts: 5053
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by daveejhitchins » Wed Sep 05, 2018 7:52 am

GAL16V8D - WinCUPL - Drop-in text file:

Code: Select all

Name     ARA_III_V1 ;
PartNo   16L8 ;
Date     23-08-18 ;
Revision 01 ;
Designer D.E.J.Hitchins ;
Company  Retro Hardware ;
Assembly Advanced ROM Adaptor III ;
Location IC2 ;
Device  g16v8a ;
/* *************** Revision History *************************************/
/*                                                                      */
/*                                                                      */
/* *************** INPUT PINS *******************************************/
PIN 1   =  NOE                     ; /* Not-Output Enable               */
PIN 2   =  ERNW                    ; /* Electron Read/Write - Master CS */
PIN 3   =  QA                      ; /* Page latch LSB                  */
PIN 6   =  T2                      ; /* CPU clock phase 2               */
PIN 8   =  MADET                   ; /* Master detect - Low if Master   */
PIN 9   =  MRNW                    ; /* Master Write - Electron N/U     */

/* *************** OUTPUT PINS ******************************************/
PIN 12  = !NCS                    ; /* Not-Chip Select                  */
PIN 13  = !OE                     ; /* Not-Output Enable on Read Only   */
PIN 19  = !RNW                    ; /* Low output Read Not-Write        */

/* *************** LOGIC EQUATIONS  *************************************/

NCS =    MADET & !NOE & T2                      /* Electron             */
      # !MADET &  ERNW & T2;                    /* Master               */

OE  =    MADET & !NOE & ERNW                    /* Elk nOE Only on read */
      # !MADET & !NOE & MRNW;                   /* MAS nOE Only on read */

RNW =   !MADET & !MRNW                          /* Master write         */
      #  MADET & !ERNW;                         /* Electron write 2     */
      
Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

User avatar
daveejhitchins
Posts: 5053
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by daveejhitchins » Wed Sep 05, 2018 10:25 am

And . . . The final schematic:
DMGC-05-09-18.JPG
And a .pdf
Retro Hardware ARA III - 05-09-18.PDF.zip
(74.61 KiB) Downloaded 19 times
Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

User avatar
Elminster
Posts: 3762
Joined: Wed Jun 20, 2012 8:09 am
Location: Essex, UK
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by Elminster » Wed Sep 05, 2018 10:37 am

As I have been trying to get my head around this Electronics thing. Isn't the GAL a bit of an over kill for what you are doing with it, couldn't you use a few 74LSHCTs? As thete is plenty of real esate left. Or would that work out more expensive?

User avatar
davidb
Posts: 2468
Joined: Sun Nov 11, 2007 10:11 pm
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by davidb » Wed Sep 05, 2018 11:02 am

It's good to see something like this - the low cost nature of it is one of the aims I had for my cartridges.

Thinking about saving pennies here and there, how about using the SST39SF010A-70-4C-PHE-ND Flash ROM instead of the 28C256? I know it's a larger components and much of its capacity would be wasted in a simple 32K ROM configuration but it's potentially quite a bit cheaper.

User avatar
Elminster
Posts: 3762
Joined: Wed Jun 20, 2012 8:09 am
Location: Essex, UK
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by Elminster » Wed Sep 05, 2018 11:07 am

Could you still get the 28pin 28c256 to work electrically in the 32pin holder? For some reason I cant see the datasheet.

People already have a lot of 28c256s floating about. Well I do, some in Electron, some in master, some in RC2014 etc. None of which would work with a 32 pin part.

User avatar
1024MAK
Posts: 9108
Joined: Mon Apr 18, 2011 4:46 pm
Location: Looking forward to summer in Somerset, UK...
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by 1024MAK » Wed Sep 05, 2018 12:05 pm

Hi Dave :D

I am interested in buying two ARA III kits if possible.

I'm happy to have the prototype boards or if you have run out of those, the 'production' boards.

Code: Select all

PCB				£2.50
28C256				£1.63
GAL 16V8 (programmed)	        £1.05
28 pin IC socket (LP)		£0.62 - Needed for 3D printed case
20 pin IC socket (LP)		£1.00 - Needed for 3D printed case
Resistor (10K or 12K)		£0.02
2 x 100n Capacitor (X7R)	£0.20
Right angled header		£0.04
Jumper				£0.05
3D printed case			£3.16
Also I would like to buy these parts:-
UM6502CE, QTY=2
R6522, QTY=4
AT28C256, QTY=2 (in addition to the two required for the ARA III)

If you can bring to Cambridge later this week, that would be good. If not, sending by post would be fine (I'm not in a rush).

Mark

User avatar
davidb
Posts: 2468
Joined: Sun Nov 11, 2007 10:11 pm
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by davidb » Wed Sep 05, 2018 1:01 pm

Elminster wrote:
Wed Sep 05, 2018 11:07 am
Could you still get the 28pin 28c256 to work electrically in the 32pin holder? For some reason I cant see the datasheet.
Not without some pin remapping which would probably involve clipping legs off the IC and using jumper wires, as far as I can tell. :(

User avatar
tricky
Posts: 3672
Joined: Tue Jun 21, 2011 8:25 am
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by tricky » Wed Sep 05, 2018 4:54 pm

No sockets for me, collection from Cambridge would be great.

User avatar
daveejhitchins
Posts: 5053
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by daveejhitchins » Wed Sep 05, 2018 5:01 pm

Elminster wrote:
Wed Sep 05, 2018 10:37 am
As I have been trying to get my head around this Electronics thing. Isn't the GAL a bit of an over kill for what you are doing with it, couldn't you use a few 74LSHCTs? As thete is plenty of real esate left. Or would that work out more expensive?
I started off trying to do it the TTL way, but soon found that as a minimum it would be two parts and most probably three (there's a challenge!) - The GAL16V8D that I have, at £1.05, does the job in one part - and it's not too much of a squeeze - keeps the board size down and only 20 pins to solder. Of course there's the added advantage that if I'd made a cock-up of the logic - it's easily re-programmable.

Dave H :D
Last edited by daveejhitchins on Thu Sep 06, 2018 7:25 am, edited 1 time in total.
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

User avatar
daveejhitchins
Posts: 5053
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by daveejhitchins » Wed Sep 05, 2018 5:11 pm

davidb wrote:
Wed Sep 05, 2018 11:02 am
Thinking about saving pennies here and there, how about using the SST39SF010A-70-4C-PHE-ND Flash ROM instead of the 28C256? I know it's a larger components and much of its capacity would be wasted in a simple 32K ROM configuration but it's potentially quite a bit cheaper.
So it is - Several problems: Slightly bigger IC socket needed (if you use sockets, that is) : I'd want to use the whole capacity, somehow :oops: : I don't have them in-stock, so it would have meant more cash layout! Also, does MartinB's Utilities work with it?

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

User avatar
daveejhitchins
Posts: 5053
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by daveejhitchins » Wed Sep 05, 2018 5:17 pm

1024MAK wrote:
Wed Sep 05, 2018 12:05 pm
If you can bring to Cambridge later this week, that would be good. If not, sending by post would be fine (I'm not in a rush).
I'll get everything ready for you, Mark . . .

Thanks - Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

User avatar
guddler
Posts: 536
Joined: Sat Apr 04, 2009 9:43 am
Location: W.Somerset
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by guddler » Wed Sep 05, 2018 5:37 pm

Could I take one with a 3D case please? I don't need it soldered or anything as I'm fine with that but I probably don't have any low profile sockets. I probably have a GAL, I'd need to check. I have a box of them, just need to check which ones they are.

In summary probably a kit please :)

PS: Have you made any kind of cutout in the case for a switch?

User avatar
daveejhitchins
Posts: 5053
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by daveejhitchins » Wed Sep 05, 2018 9:44 pm

guddler wrote:
Wed Sep 05, 2018 5:37 pm
Could I take one with a 3D case please? I don't need it soldered or anything as I'm fine with that but I probably don't have any low profile sockets. I probably have a GAL, I'd need to check. I have a box of them, just need to check which ones they are.

In summary probably a kit please :)

PS: Have you made any kind of cutout in the case for a switch?
PM sent . . . Re the switch - Watch this space :wink:

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

User avatar
tricky
Posts: 3672
Joined: Tue Jun 21, 2011 8:25 am
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by tricky » Thu Sep 06, 2018 6:20 am

I was also thinking about a switch, but to swap the two 16K slots over (not ROM_QA/A14 I guess).
I'm happy to make a few mods if necessary, and I guess there is a spare pin on the GAL that could provide it.
The reason is that when my games are loaded as utility ROMs, they will "auto-boot" if they are in SLOT 0 (untested on HW).
The idea is two have two 16K games and be able to swap which one boots if the cartridge is in the far slot (may be of interest to Dave).
I guess that these cartridges are really good value and this isn't really necessary :roll:

I was actually planning on making a more basic cartridge with just a 32KB EPROM, cap, transistor and switch; but that is a story for another thread.

User avatar
davidb
Posts: 2468
Joined: Sun Nov 11, 2007 10:11 pm
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by davidb » Thu Sep 06, 2018 10:43 am

daveejhitchins wrote:
Wed Sep 05, 2018 5:11 pm
So it is - Several problems: Slightly bigger IC socket needed (if you use sockets, that is) : I'd want to use the whole capacity, somehow :oops: : I don't have them in-stock, so it would have meant more cash layout! Also, does MartinB's Utilities work with it?
Using the whole capacity would mean using jumpers or switches if we were keeping it inexpensive; otherwise it would need the paging logic of the MGC or my Multi-ROM cartridge. It's programmed in the same way as the 28C256 so I think MartinB's utilities would work with it.

User avatar
Elminster
Posts: 3762
Joined: Wed Jun 20, 2012 8:09 am
Location: Essex, UK
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by Elminster » Thu Sep 06, 2018 12:39 pm

I wonder if it would be feasible (but maybe not cheap). To put a 32 pin socket on and then use a jumper and more of the GAL so select what signals go where. Best of both worlds then.

User avatar
1024MAK
Posts: 9108
Joined: Mon Apr 18, 2011 4:46 pm
Location: Looking forward to summer in Somerset, UK...
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by 1024MAK » Sat Sep 08, 2018 5:27 pm

Is this drifting into feature creep territory!

Mark
Last edited by 1024MAK on Sat Sep 08, 2018 5:28 pm, edited 1 time in total.

User avatar
guddler
Posts: 536
Joined: Sat Apr 04, 2009 9:43 am
Location: W.Somerset
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by guddler » Sat Sep 08, 2018 6:17 pm

daveejhitchins wrote:
Wed Sep 05, 2018 9:44 pm
Re the switch - Watch this space :wink:
Does that perhaps mean we might be able to connect the jumper to the gal instead of using a switch or something like that??

[EDIT] Never mind - having just looked at the schematic and the GAL logic I think I may have misinterpreted the intention of the switch :D
Last edited by guddler on Sat Sep 08, 2018 6:42 pm, edited 1 time in total.

User avatar
CMcDougall
Posts: 6722
Joined: Wed Feb 02, 2005 3:13 pm
Location: Shadow in a Valley of Scotland
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by CMcDougall » Sat Sep 08, 2018 6:23 pm

^seems that way Mark 8)

next folk will want a build in Blu-Ray player & full 4k TV :lol:

nice little gizmo Dave ,
PS your tape & extra eprom is with Postman Pat :wink:
ImageImageImage

User avatar
guddler
Posts: 536
Joined: Sat Apr 04, 2009 9:43 am
Location: W.Somerset
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by guddler » Sat Sep 08, 2018 8:55 pm

Happy to report that mine is all built and working - many thanks, one happy chappy here :D :D

I'll let someone else snag one of these cheap pre-production ones but when they go into production then I think I'll grab another for slots 2 / 3.

User avatar
daveejhitchins
Posts: 5053
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by daveejhitchins » Sun Sep 09, 2018 8:39 am

CMcDougall wrote:
Sat Sep 08, 2018 6:23 pm
nice little gizmo Dave ,
PS your tape & extra eprom is with Postman Pat :wink:
Thanks and thanks Col . . . :D

Dave H :D

p.s. I'm planning to modify the case to take a small switch for the write protection. I had planned to hack a case here at Cambridge, however, I don't think I can do it neatly enough - hence a small mod to the case design. But that's for when I get back from holiday . . .
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

User avatar
jgharston
Posts: 3628
Joined: Thu Sep 24, 2009 11:22 am
Location: Whitby/Sheffield
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by jgharston » Mon Sep 10, 2018 6:06 pm

Forgot to ask at ABUG, but would a AQR version of this be do-able? 16 banks of 16K of persistant storage, selectable with the *AQRPAGE command already in the AP6 support ROM.

Edit: and regarding our chat about the 2x16K memories, make the paging register at &FCFC readable as well as writable! :)
Last edited by jgharston on Mon Sep 10, 2018 6:08 pm, edited 1 time in total.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

User avatar
daveejhitchins
Posts: 5053
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham
Contact:

Re: Retro Hardware ARA III - Low Cost Writable ROM Cartridge - For the Electron and Master

Post by daveejhitchins » Wed Sep 12, 2018 8:58 pm

jgharston wrote:
Mon Sep 10, 2018 6:06 pm
Forgot to ask at ABUG, but would a AQR version of this be do-able? 16 banks of 16K of persistant storage, selectable with the *AQRPAGE command already in the AP6 support ROM.

Edit: and regarding our chat about the 2x16K memories, make the paging register at &FCFC readable as well as writable! :)
The AQR is on the list. I actually bought the memory for it ages ago - chance purchase. I plan to have 2 x AQR in the same case - But not RAM - So, I would think, all of the old software wouldn't work without extensive rework - even then the printer buffer and RAM disc would be out!

It would be nice to have one half RAM and the other EEPROM - but . . .

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

Post Reply