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 Forum: Hardware in general   Topic: Bit Serial CPUs

 Post subject: Re: Bit Serial CPUs
Posted: Fri Nov 20, 2020 11:42 pm 

Replies: 19
Views: 7684

Ed, It occurred to me that a lot of peripherals that we use now rely on SPI, so my rational for this project is to create a very small cpu which fits comfortably with SPI memory and devices. There is a plethora of SPI memory devices available, SRAM, FRAM, Flash, all of which have a very similar acce...

 Forum: Hardware in general   Topic: Bit Serial CPUs

 Post subject: Bit Serial CPUs
Posted: Fri Nov 20, 2020 4:59 pm 

Replies: 19
Views: 7684

Lockdown 2.0 here in the UK has inspired me to start looking at bit serial cpu architectures this week. Almost exclusively, the immediate post-WW2 machines were bit serial - as this was the only way to keep the hardware cost manageable. Bit serial allowed early machines to have long wordsizes - such...

 Forum: CPU/MCU choices and designs   Topic: Some Minimal Instruction Set CPUs

Posted: Fri Nov 13, 2020 12:32 pm 

Replies: 37
Views: 42664

Nice to see a bit of home-built TTL computing history. However it had a chip-count of 35 ICs, of which 8 were the RAM. The instruction set was very minimal - leaving a lot of scope for future improvements. I would have thought that using a pair of 74181s as the ALU would have encouraged a more diver...

 Forum: Simulation and emulation   Topic: Simulated PDP-8, FOCAL-69 & Lunar Lander run on Teensy 4.0

Posted: Sun Sep 13, 2020 8:36 am 

Replies: 2
Views: 3740

Would I be right in thinking the Teensy has a USB port and appears as a serial device to the host? And can be powered over the USB too? Ed - correct on both points. Theres a micro USB connector at one end of the board which provides one means to power the board and appears as a serial port to the h...

 Forum: Simulation and emulation   Topic: Simulated PDP-8, FOCAL-69 & Lunar Lander run on Teensy 4.0

Posted: Sun Sep 13, 2020 12:57 am 

Replies: 2
Views: 3740

The Teensy 4.0 is a small footprint, breadboard friendly, 600MHz ARM Cortex M7 microcontroller. I bought a handful of these earlier this week and I am finding it an ideal platform to simulate experimental or retro cpus. My first experiments were with a 6502 simulation, with ehBASIC preloaded into th...

 Forum: General Discussions   Topic: Teensy 4.0 - 600MHz ARM Cortex M7 dev-board

Posted: Wed Sep 09, 2020 3:22 pm 

Replies: 2
Views: 3266

Hi Ed, Teensy 4.0 and 4.1 are now available in the UK from CoolComponents, Pimoroni, PiHut and HobbyTronics. Check the PJRC site for a full list of their Worldwide Distributors. Priced at between £18 and £29 they offer a small breadboard friendly form factor and at 600MHz at least 150% of the perfor...

 Forum: General Discussions   Topic: In Memoriam - Marcel van Kervinck

Posted: Wed May 27, 2020 10:11 am 

Replies: 2
Views: 4359

It is with deepest regrets that I announce the death on Tuesday 25th May of Marcel van Kervinck - the creator of the Gigatron TTL Computer. Marcel passed peacefully following a long illness and to regular readers of the Gigatron forum, it was clear that in recent weeks he had increasing health probl...

 Forum: CPU/MCU choices and designs   Topic: Suite-16 (formerly Bitslice using currently available TTL)

Posted: Fri Jan 17, 2020 8:39 pm 

Replies: 52
Views: 23501

Hi All - and Happy New Year - although we are already more than half way through January. This post is by way of an update, because I realise that the Suite-16 project has been fairly quiet since early November. In mid-November I went over to California for a couple of weeks - firstly to attend Fort...

 Forum: General Discussions   Topic: New transistor design could revolutionise digital, analogue

Posted: Fri Nov 08, 2019 2:24 pm 

Replies: 2
Views: 2630

Ed, There are also patents (pending) for their Instantaneous Processor Unit (IPU) which sounds like it can process analogue signals without the complexity of ADC then digital processing then DAC. The sort of application might include a LED lighting controller, power factor controller for switched mo...

 Forum: General Discussions   Topic: New transistor design could revolutionise digital, analogue

Posted: Fri Nov 08, 2019 12:52 pm 

Replies: 2
Views: 2630

Hi All, It's not everyday that you read about a fundamental new kind of transistor that could revolutionise the way we produce ICs. Whilst Intel and their competitors are chasing 7nm technology with multi-billion investments in fabs and design teams, this new device is aiming to have appeal for the ...

 Forum: CPU/MCU choices and designs   Topic: Suite-16 (formerly Bitslice using currently available TTL)

Posted: Mon Nov 04, 2019 11:01 am 

Replies: 52
Views: 23501

Yes, Two minds clearly better than one! And Frank's TASM contribution has come at just the right stage in the project. After about 2 weeks since Hello World!" - I think that I have probably hand-assembled enough code to prove what can be done, and also highlight any deficiencies in the instruct...

 Forum: CPU/MCU choices and designs   Topic: Suite-16 (formerly Bitslice using currently available TTL)

Posted: Sat Nov 02, 2019 10:52 pm 

Replies: 52
Views: 23501

This week there has not been so much obvious progress with Suite-16 - but I have been tying up a few loose ends. It became obvious from my early coding ventures that the instruction set was lacking the means to handle 8-bit values, without going through some rather clumsy register operations. To rem...

 Forum: CPU/MCU choices and designs   Topic: Suite-16 (formerly Bitslice using currently available TTL)

Posted: Mon Oct 28, 2019 1:26 pm 

Replies: 52
Views: 23501

Previously I had been simulating the Suite-16 cpu on an MSP430 Launchpad board with FRAM. I noted that despite it being a 16-bit processor, the performance was not so good, so I have swapped over to a Nucleo STM32H743 board which has a 400MHz ARM processor. I'm still using the Arduino IDE to develop...

 Forum: CPU/MCU choices and designs   Topic: Suite-16 (formerly Bitslice using currently available TTL)

Posted: Sat Oct 26, 2019 8:24 am 

Replies: 52
Views: 23501

Ed, I did have some reservations about entering the dark lair of "self modifying code". When I looked at EDSAC simulation a couple of years back, it was the first lesson you learned - in order to get anything useful done. I now need to look at the new instructions and just make sure I can ...

 Forum: CPU/MCU choices and designs   Topic: Suite-16 (formerly Bitslice using currently available TTL)

Posted: Sat Oct 26, 2019 7:53 am 

Replies: 52
Views: 23501

Hi Ed, It did actually involve quite a few instructions, (half a dozen actually), because of current limitations in the instruction set. Suite-16 is currently only using an 8-bit jump address which is stored in the payload section of the instruction. If we extend this to a 16-bit jump, the target ad...
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