11

You won't find a 32-bit processor that had a clock speed slow enough to work with a breadboard type of layout, and in any case the chip would have too many pins to package that way (the address and data bus would take 64 pins, without anything else). A 32-bit data bus doesn't mean that data is always transferred 32 bits at a time - some instructions only ...


10

To expand on the 68000-family suggestion from @user and @Stefan Skoglund's comments, in community wiki form: The 68000 is a 1979 processor with a 32-bit instruction set that appears still to be supported by GCC*. It was initially available as a 64-pin DIP, using a 24-bit address bus and 16-bit data bus. Additional complexity over an 8-bit machine is: it may ...


8

[...] but all the chips I find are either 8/16 bit or have so many pins they need BGA, and none of them have anything clearly labelled as an address bus, so there must be a good reason it doesn't exist. I might just be using the wrong search terms or know way too little about electronics, but I can't seem to be able to find anything about this. If somebody ...


8

As far as I can tell, the first edition of the IBM 5150 Technical Reference is the only IBM manual which mentions 45 cylinders. Few Technical References document the FDC, which is where the “45 cylinder” mention appears, but those that do, other than the 5150 first edition, don’t reproduce this — see for example the first edition of the IBM 5160 Technical ...


7

TL;DR: If I connect it other way would any components blow? No. Let's have a look at the circuitry All following schematics are taken from the 1993 manual. To start with, the wall wart is delivering 9..10V (depending on region *1) DC. (Page 7 lower right corner, B6/B7) Polarity is not mentioned at all - not here nor in any other overview or part list. ...


6

That's CN13. The pins are documented here and have address and data lines as you would expect for memory, not the signals you would need for a floppy drive. I would connect a Gotek to the DB-23 connector on the rear panel.


5

You can actually generate a "spurious interrupt" condition on the Atari ST with its MFP (68901) - Not on purpose, but rather because of a glitch in the Motorola 68901 - If you disable interrupts on the MFP exactly at the point when the CPU starts an IACK cycle (i.e with the last instructions before the /INT), it will not provide a vector, the CPU ...


5

Apparently, it was not the only one. I own a Kempston Pro Joystick Interface, which has one joystick port for Kempston/Cursor protocols, two ports for Sinclair 1/2 protocols, and a "games cartridge port". (the epoxy is an attempt of mine to hold in place the plastic part of the edge connector).


5

Floppy disk drives could usually mechanically access more than 40 tracks, but only 40 were actually used, "formatted". First track is on the outer edge of the disk, there is a detector than signals when the disk head has reached the edge. Other tracks are reached by moving by a known number of phases a stepping motor. Simple drives use "CAV&...


4

The primary reason you don't see open address buses is clock speed. At the >100Mhz speeds modern processor's chipset buses operate at, having multiple things connected to an electrical line results in complex wave behaviors. Thus it is a lot easier to have a single point to point bus to a chipset IC, which handles fanout to the various controllers. A ...


4

Some microcontrollers have I/O pins that can be configured to operate as a memory bus for part of their address space, with configurable wait states. Most of the applications which would need more memory than could fit on a chip would either also demand more speed than could be achieved with all code having to be conveyed on an external bus, or could get by ...


4

Welcome to the site (I am also very new). If the reason for your question was as you said "looking for a simple processor that I could just buy and plug into a breadboard or maybe hand-solder if necessary, and just mess around with as I learn about electronics and computer hardware.",what was wrong with 6502 / why do you need a 32-bit one? If you ...


4

Sirius 1 (aka Victor 5000 in the US) had a programmable character generator on a nice 10x16 matrix giving a good 800x400 resolution. This was a very nice PC and much better than the crap IBM came up with. (8088@5Mhz, up to 896K RAM, MS-DOS or CP/M 86, 800K floppies, soft control for monitor,).


3

Looking at the specs from your link, CPU: AMD 8085 RAM: 32K ROM: 32K GPU: Plessey MR9735-02 (Viewdata processor) with 1K page memory RAM Modem: Philips SAA5070 "LUCY" Monitor: 5" integrated Keyboard: integrated that's plenty to run games. Still, I doubt that games did exist, because they built 10,000 but only sold 5000 so the volume was ...


3

From the question, I think you already understand the basic function of the DMACON registers. In a nutshell, any form of DMA has to be enabled under software control by the programmer. This because the DMA transfers are meaningless until the programmer has first setup the buffers of data, and associated pointer registers, that will be used by the DMA ...


3

Any computer with a serial terminal interface supports redefineable character sets. Just plug in a VT220 terminal. This is a curmudgeonly way of saying it's not "the computer", it's a specific display device that supports loadable characters. I recall that, in the days when VMS MAIL would happily display whatever it got in a mail message, sending ...


3

Half of the character ROM of Digital Equipment Corporation's DECmate-II was user-definable. No one ever used this feature and it was dropped from subsequent models.


3

The big value-add feature advertised for the Hercules Graphics Card Plus was RamFont, or re-definable character sets. Custom characters could be uploaded into the card, and rendered as part of a 3072 character set. (In contrast to the 256 fixed characters of the MDA, CGA, and original Hercules cards). Driver support was available to use this feature in a few ...


3

The MOS MCS6500 microprocessor family datasheet from May, 1976 indicates that: "All versions of the microprocessor are available in 1 MHz and 2 MHz maximum operating frequencies." The document is archived here: http://archive.6502.org/datasheets/mos_6500_mpu_preliminary_may_1976.pdf


2

High-end processors do still expose their busses- but you typically need special support chips to do anything useful with them. In the past I was involved with an (AMD) '386 design, but it also had to have an external bus exchange chip to handle all possible combinations of 32/16/8-bit accesses. These days, if you can't find the kind of chip you want, build ...


2

Based upon a quick look at the PAL Megadrive II schematics, it appears as if the the power input is first routed through a common mode choke(for which polarity does not matter) before it goes onto the power switch. After the power switch, it is routed through a reverse polarity protection diode before it is fed to the input of a LM7805 regulator to provide ...


2

The Olympia People computer had a fully-redefinable character set. This was used to implement the 'national character support' it's marketing touted. While a colour display with graphical add-in card was an optional extra the machine shipped by default with only a text mode. IIRC font data was stored at $E4000 in memory with 32 bytes per character, ...


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