New answers tagged

1

A later example was the original RS/6000 workstation's POWER1 (or RIOS-1) CPU, which was later developed into the PowerPC architecture. Each of the eight VLSI chips contained one major subsystem, along with associated registers and cache; each line in the following diagram is a 32-bit bus. Instruction Cache Unit (ICU) - L1 I-cache, I-TLB, Program Counter (...


2

Additional information to complement the answer by Fuzzy_Bunnys: 1) An Forth chip I like very much is the J1. It even comes with the Verilog source. It runs e.g. on an Xilinx Spartan 3E FPGA at 80 MHz, and is used for a real-word application (a Ethernet camera). It has a high code density, but a very simple "unencoded" instruction format (even simpler than ...


2

I've collected a number of resources in this answer that I've managed to find with additional searching on the internet. Additionally my copy of Stack Computers arrived in the mail and has been very useful. I've split links into professional/academic vs hobbyist. PROFESSIONAL/ACADEMIC Phil Koopman's Stack Computers dedicates its fourth chapter to ...


2

I think the idea behind UHRES was to have VRAM connected to an indipendent DAC/CLUT. The VRAM has a second data port where it outputs the content of a row. This output was connected to the DAC. Agnus had the responsibility to configure the second data port at each scanline. For this reason, it emits, at the 2nd cycle, on the RGA bus a 078 (BPLHDAT) and on ...


0

The kind of circuitry needed/used to drive a tape recorder that only offers audio connections, for purposes of storing digital data from a computer or similar device ... IS A MODEM. Even if is not a (purpose built) telephone modem (which is usually implied when people speak of modems these days).


1

I think you are not taking into account both of the new video modes supported by the Amiga ECS chipset using the higher dot clock: Super-Hires Mode: 1280 pixel horizontal resolution, interlaced or non-interlaced lines, with a 15.7 kHz horizontal frequency. Productivity Mode: 640 pixel horizontal resolution (same as Hires), 480 lines, with a 31 kHz ...


1

The ECS chipset appears to have had support for a new UHRES mode added, but it was never completed. It seems to be related to the Ranger chipset developed by Jay Miner. The idea seems to have been to move display fetch off Agnus to a separate chip with its own VRAM, which was never completed. That would allow greater bandwidth to video memory, one of the ...


2

Tantalum is a good conductor which can easily form a thin layer of oxide on its surface, which in turn acts as a good dielectric. This makes it a very good material for constructing electronic capacitors. In this form it was probably used as soon as semiconductor diodes and transistors became the principal computing medium. It is also used for making high-...


1

I am no expert in this topic, but the other comments and answer lack the purpose of the capacitor usage OP is asked for, so here it is: If you look at any digital circuit it contains gates. The gates are like a power switch - they turn on/off. The problem is that if you have a complicated circuit with many gates (like CPU) with very fast speeds, then to ...


4

It is not used so much as it used to. It tends to be replaced by ceramic and polymer electrolytics as tantalums have their limitations. But back in the 1970s the electronic calculators needed small capacitors with high capacitance and low ESR (impedance) for power supply bypass capacitors, and tantalum capacitor technology had been improving so much over the ...


0

As the question specifically states that this is about common home computers of the early 1980s, the answer has to be no. To interface with the analogue telephone system, a modem is required (internal or external). Provision of an internal modem would add to the cost (both in bill-of-materials and in testing and regulatory compliance), and networking was ...


-2

A direct electrical connection between a phone line and a computer would immediately destroy the computer, because the phone line carries a 50V DC supply to power telephones connected to it. It's possible to get over that hurdle, of course, by inserting an isolating audio transformer or an acoustic coupler into the connection. You must then contend with ...


5

As other answers note, the data rate varied considerably between machines. I'll give two concrete examples from popular machines - the BBC Micro and the Commodore 64. Acorn adopted the 300-baud "Kansas City" or "CUTS" format for their early machines, and adapted this for higher performance with the BBC Micro. The basic baud rate is 1200, stored using ...


3

The first mention of SPI that I can find is in the Motorola data book Single-chip Microcomputer Data from 1984.¹ The three devices in that book that support "Serial Peripheral Interface" are the 6505K2/K3, 6505S2 and 68HC11A4. The data sheets for all of these are marked "This document contains information on a product under development. Motorola reserves ...


8

The Apollo Guidance Computer had fixed and erasable memory. The former (which is the focus of this question) contained instructions and constants, and was functionally equivalent to ROM. The latter was where data was stored, and was functionally equivalent to RAM. The response to parity errors in either memory was the same. The effect of a failed memory ...


8

The first Motorola microcontrollers having an integrated SPI interface were the MC6805S2, MC6805K2 and MC6805K3, available in 1983. See the Microprocessors and Peripherals databook of the time. I doubt other manufacturers had this available before Motorola (if we exclude discrete logic implementations using shift registers, and only consider complete MCUs ...


3

What were the first chips with hardware support for SPI? Asking for any chip here is a bit fruitless, as this would end up by naming some synchronous serial chip of the 74xx line or even before. After all, SPI wasn't really a new invention but a formal description of the interface of next to any shift register. The SPI block was meant to offer a generic, ...


6

I confirmed this worked as expected, using Am386/DX-40 + Intel 387 co-processor. The trick with the Am386 is having separate clock for CPU/co-processor, as the former runs at 40 MHz and the latter at 33 MHz. The UMC-386 mainboard supports this configuration fine.


1

I have a lateral thinking answer which may be of greater interest if you have the equipment: Instead of using a sound chip, connect your project to a MIDI instrument through a MIDI-compatible serial connection. Information about the physical specifications of MIDI can be found here. http://www.personal.kent.edu/~sbirch/Music_Production/MP-II/MIDI/...


2

Since the 'Manchester Baby' is mentioned above, I thought I might mention this one, since it's very interesting, for those who may accept game-sprite like objects instead of text, although I don't. The MIDSAC computer computer had a billiards game in 1954, very impressive .


6

AY-3-8910 https://en.wikipedia.org/wiki/General_Instrument_AY-3-8910 http://www.vgmpf.com/Wiki/index.php/AY-3-8910 Pretty popular chip used in arcade machines and home computers. eBay has clones for quite cheap. Yamaha YM3812 (OPL2) https://en.wikipedia.org/wiki/Yamaha_YM3812 http://www.vgmpf.com/Wiki/index.php?title=YM3812 Used in home computer sound ...


5

There is a project called SwinSID that uses an ATMega to replicate the original C64 SID chip here: SwinSID based on ATMEGA88. You could conceivably use an ATMega with the firmware developed by this project to get what you are looking for. I've no idea if this solution is like is using a bazooka to shoot a fly, or what the cost looks like, but at a minimum ...


2

Sounds like a job for SAA1099P. It is a 6 channel square wave tone genrator with stereo output. Each channel has volume control and it includes two envelope generators and two noise channels. While it directly does not support triagle and sawtooth waveforms, the envelope generator has these waveforms so low frequency basses are available as triangle and ...


13

If you're comfortable with programming microcontrollers already, I suggest you just use another microcontroller and adapt its output to be an audio signal. You can use a DSP-type with an audio output (Microchip dsPIC has stereo audio out off the top of my head, your favourite brand may have their own) if you want potential stereo, fine grained control with ...


15

May I recommend the TI SN76489, then? 3 channels + noise, clocked from a 4 MHz input. Small, cheap. Sounds like chiptunes. Simple to program. Easy to get surplus. Only drawbacks: it powers on producing a loud continuous tone. You need logic at startup to tell it to make some other noise, or preferably no noise at all. Hence the BBC Micro's two-tone startup ...


4

There were several cards, in the mid 1980s, based on use of 64 KiB. Except that it was usually not to use full 64 Kib, but to get RAM at the right location some (game) program wanted it. For example this page shows three different boards of that time frame. The main issue with RAM in the VIC20 is less the amount of RAM, than that its use swaps around, ...


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