Search found 69 matches

by monsonite
08 Jun 2019, 09:42
Forum: Hardware and software hacking
Topic: dual ported SRAM for co-processing
Replies: 5
Views: 1257

Re: dual ported SRAM for co-processing

They are listed in the 1983 TTL Handbook - see page 2-404 in the link below http://bitsavers.trailing-edge.com/components/ti/_dataBooks/1983_TI_ALS_AL_Logic_Circuits_Data_Book.pdf It looks like they are an extended version of the 74xx670 which contained 4 x 4bit registers - which did appear much ear...
by monsonite
30 May 2019, 22:26
Forum: Escape Meta Alt Control Shift
Topic: A TTL Computer Kit from 1974
Replies: 2
Views: 2006

Re: A TTL Computer Kit from 1974

Hi Marcel, I also found the Prosser and Winkel book - and found it very interesting. To find the archive on the LD12, was the "icing on the cake". Two weeks on holiday in Portugal - I have plenty of reading time. I was not aware of the Elektor "Computer 74", but the anycpu.org has details of the "We...
by monsonite
29 May 2019, 17:18
Forum: Escape Meta Alt Control Shift
Topic: A TTL Computer Kit from 1974
Replies: 2
Views: 2006

A TTL Computer Kit from 1974

Back in Autumn 1974, the engineers at MITS in Albuquerque were busy developing what was going to become the ground-breaking Altair 8800 microcomputer - for shipment to Popular Electronics Magazine, in time for their January 1975 edition. The Altair 8800 was the first, real commercial microcomputer k...
by monsonite
06 May 2019, 18:53
Forum: Hardware and software hacking
Topic: New form factor Gigatron.
Replies: 6
Views: 3282

Re: New form factor Gigatron.

Hi All, After a few hours with EagleCAD, I have a proof of concept, reduced format pcb layout. The size is 200 x 100 mm. Power and ground planes are on the inner 2 layers, with all signals on the top or bottom layers. I have included an 8-bit output port and an 8-bit input port - as per the proposed...
by monsonite
05 May 2019, 19:14
Forum: Hardware and software hacking
Topic: Expansion bus
Replies: 96
Views: 33370

Re: Expansion bus

xopr,

I like your Tiny BASIC hack for code entry - nice.

I suppose when Tiny BASIC was written, PEEK, POKE and USR were the "tactical nukes" of the language.

I'll get a chance to try that tomorrow.

4 seconds to parse itself - is that with Mode 0 (no blank lines) video?

Ken
by monsonite
05 May 2019, 17:41
Forum: Hardware and software hacking
Topic: New form factor Gigatron.
Replies: 6
Views: 3282

Re: New form factor Gigatron.

Hi All, Attached is a PDF giving an overview of the Gigatron design. I have hypothetically split the design into two roughly equal parts, loosely called "ALU" and "Memory" and then placed the sub-systems between these "camps" so as to minimise the number of signals that have to pass between them. Th...
by monsonite
04 May 2019, 20:00
Forum: Hardware and software hacking
Topic: New form factor Gigatron.
Replies: 6
Views: 3282

New form factor Gigatron.

Hi All, During the life cycle of a computer, - it is not uncommon for it to undergo a series of design changes - mainly to reduce costs or to take advantage of new technology. The classic example of this metamorphosis is the PDP-8 minicomputer, which was conceived in the era of DTL (diode transistor...
by monsonite
30 Apr 2019, 18:28
Forum: Kit assembly gallery
Topic: Assembling Gigatron the hard way
Replies: 29
Views: 6947

Re: Assembling Gigatron the hard way

Well done in tracking down your instruction error to a wiring mistake. I think you deserve to win a free pcb for your perseverance and endurance ;) I think you will make much faster progress from this point onwards - and you sure have learned a lot about the machine's instruction set and architectur...
by monsonite
30 Apr 2019, 18:13
Forum: Hardware and software hacking
Topic: Expansion bus
Replies: 96
Views: 33370

Re: Expansion bus

With extra hardware comes the necessity of extra software - and with more software the requirement for more memory. Non volatile memory would be attractive - One option might be to fit a 32K x 8 ferroelectric RAM - which retains its data after power off. This could be added to the expansion board a...
by monsonite
30 Apr 2019, 17:55
Forum: Hardware and software hacking
Topic: 10MHz, 12.5MHz and Beyond!
Replies: 24
Views: 5875

Re: 10MHz, 12.5MHz and Beyond!

Further progress this evening with the arrival of a 13MHz crystal. Tetris still runs perfectly, WozMon runs perfectly, TinyBASIC runs intermittently. Mandelbrot runs for several "loops" but crashes to black screen when trying to render the 24th scan line from the bottom of the screen. At 12MHz all i...