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22

The following is an excerpt from the article César Hernández Bañó and I wrote about the internals of the Inves Spectrum+, exposed after a detailed work of reverse enginnering. First, some background: César is the author of the first (and AFAIK, only) emulator that handles the oddities of the Inves Spectrum+. With time, his emulator has evolved and now it ...


14

The ISO 7185 Pascal standard, section 6.4.3.5 "File-types", says (my emphasis): There shall be a file-type that is denoted by the required structured-type-identifier text. The structure of the type denoted by text shall define an additional sequence-type whose values shall be designated lines. A line shall be a sequence cs ~S(end-of-line), where ...


13

I nominate the AY-3-8912, which is a sound generator that also has eight programmable input/output pins — set them as input or output, set or get their level — in a 28-pin package. It sits between the 8910 (16 IO lines, 40-pin package) and the 8913 (no IO, just the audio, 24-pin package).


12

On the 8088 and 8086, execution involves two parallel processes--memory access and internal computation--and will be limited by the speed of whichever is slower. Generally, on the 8088 execution speed will be limited by memory access, while the 8086 will be better balanced. Every memory cycle on the 8088 or 8086 takes a minimum of four cycles, and on most ...


11

You can have a look at how simh, which emulates quite a few computer systems that had punch cards, paper tape, magnetic tape, harddisks, floppy disks, printer and terminals, handle it. Basically most kind of storage mediums (including paper tape) are mapped to a file. The printer is also mapped to file. Terminals are mapped to some kind of interface you can ...


10

Of course. After all, the number of pins is related to the task at hand. No manufacturer would choose a package with more pins than necessary. Examples of main families are: (Excluding support chips, like priority encoder, status decoder or bus drivers) Motorola 6800 family MC6840 - PTM - Programmable Timer (28 pin) MC6850 - ACIA - Asynchronous ...


10

I am afraid that the answer is "it could take any time, depending on circumstances and the real WAIT condition". WAIT states have unpredictable length, so there is no exact way to answer your question. The general answer, theoreticaly valid for every CPU (and really valid for the most of 8bit CPUs), is: Take an "instruction timing chart" ...


7

I have the following assembly code for 8086 To start with basic timing for 8086 (*1) in CPU clocks is 21 clock cycles. MOV AL,[BX] (*2) 13 cycles, consisting of 8 cycles for the instruction (MOV reg8,mem) plus 5 to calculate the address from [BX]. Since it's a byte access, no penalty for misalignment can happen. OUT DX, AL 8 cycles, all for the ...


5

Peter Onion's Elliott 803 emulator tries to replicate the experience of using an 803 in a 3D, almost VR, setting. Virtual paper tapes are used to load programs and data. Doug W. Jones's Punched Cards pages have more on how punched cards were used than almost anywhere else. The simh emulator uses Doug's punched card library for managing card inputs for ...


5

Not too sure about resources, actually. But, I can walk you through the logic I used when I wrote an (unpublished) emulator for BESK, a machine that had paper tape for input, either in "5-bit teletype code" mode or "4-bit binary number" (using one channel as a "there's data" indicator) and for output had a printer (well, an ...


4

(You may as well want to take a look at the manual, like p.2-5 of the September 1975 Manual) During the execution of an IN or OUT instruction [..], how does the Intel 8080 react to its READY pin going down? Operation is the same for all M cycles, independent of memory or I/O, as seen here: (Taken from p.2-8 of the 8080 Micro Computer Systems User's Manual ...


3

LCD as mentioned before your display init is not correct (too fast) you do not need to check busy flag you just need to add waits... This is my driver for LCD1602 on AVR32 which uses the same LCD controller using 4bit interface an 2x16 character LCD: //------------------------------------------------------------------------------------------ #ifndef ...


2

I don't know of any online resources that will teach you how to handle emulation of I/O devices, aside from looking at the source code of emulators that do this. There aren't any hard and fast rules about how an emulated I/O device should be mapped to 'real' I/O -- just do it however it's convenient for you and your users. Some mappings are natural, such ...


2

Speaking of punched cards, there are several conventions used to encode arbitrary combinations of punches, usually akin to Base64, so that 80 columns are encoded into 160 printable ASCII characters. Thus, if a line is no more than 80 characters long, it represents a text card, converted into the appropriate encoding, otherwise if it is exactly 160 characters ...


1

what instructions/orders were available to interface with them? While the thesis you linked only describes paper tape and typewriter, we can do an educated guess based on this description, compared with the general format of an "order" (instruction) as described throughout the thesis, and the binary format of an order as described in appendix B. ...


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