- #Imsai 8080 emulator raspberry serial
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- #Imsai 8080 emulator raspberry software
So that a reset will always reset the flipflops back to zero. The RC2014’s RESET pin is connected to the clear pin of the flipflops, Writing to the bank select port clocks D0 and D1 into a pair of flipflops I couldn't find a schematic or explanation for the "official" RC2014 bank switching, but Scottīaker's blog has a well-documented example of a bank-switching implementation (as well as many other excellent RC2014-related resources): On the RC2014, this is implemented with just 5 TTL chips.
#Imsai 8080 emulator raspberry software
The software tells the memory hardware to change theīank by writing to an I/O port. The CPU just puts addresses on theīus and the memory hardware does whatever it wants. Note that this is notĪ CPU feature! The CPU neither knows nor cares about the memory layout.
It is possible to use bank switching to mapĭifferent parts of the 512K into the 64K address space at any given time. The Z80 has a 16-bit address bus and therefore only 64K of address space, so what's the use in having 512K of RAM? How it is meant to work, or whether I have not enabled it, so for now I need to manually reset it every time I switch it on. Has a power-on reset function, so that it can automatically reset the CPU when power is applied, but I am not entirely sure
#Imsai 8080 emulator raspberry serial
Hitting the reset button, and then interacting with it over the USB serial cable. With the parts assembled, it's just a case of plugging a USB FTDI cable into a serial port header, switching the machine on, When I'd finished, I only had 1 resistor left over, and the machine seems to run OK so it can't have been an important one. If you solder all 40 pins and then decide you don't like the angle it's mounted at, you'll have a tough job fixing it. I like to solder just one pin at first, and then push the part down with my finger while I re-melt the solder, to make sure it sits niceĪnd flat. If you're playing along at home, I'd recommend taking the time to make sure the pin headers and IC sockets are properly seated against the board. It took me many hours over 2 sittings toįinish soldering up what I've got so far. That's already over 1000 pins,Īnd there are more headers, resistors, capacitors, etc. Then you have a corresponding 40+ pins per card for the backplane plug,Ĥ0 pins each for CPU, ROM, RAM, and serial controller, and 13 other 14- and 16-pin ICs. Even though not all of the "enhanced" slots have the headers installed, the backplane socketsĪlone are 5*60 + 7*40 = 580 solder joints. I chose the all-singing all-dancing "Zed Pro" variant of the official kit, which comes withĪ 12-slot "enhanced" backplane, 512K ROM, 512K RAM, dual clocks, and dual serial ports. Various storage modules, and also other CPU options, including the Z180 and the 6502.
#Imsai 8080 emulator raspberry upgrade
The RC2014 kits, and various upgrade modules, are available from the RFC2795 Ltd Tindie Store,Īnd there are also various other modules available from other sellers, including "single-board computer" variants, a video card, The "enhanced" backplane has an additional 20 pins, incorporating a handful of CPU lines that were missingįrom the original bus, an additional 8 pins of data bus for potential expansion to 16-bit CPUs, and 4Īs far as I'm aware, it's not possible to buy a fully-assembled RC2014, they are only available in kit form. The standard backplane has 40 pins, of which 4 are unassigned and can be used for whatever you want.
Rather than the more common card edge connector Given me a much better understanding of how a CPU actually interacts with the otherįor convenience of hobbyist use, the RC2014 uses 0.1" pin headers to plug into the backplane, Has no special place, it's just another module connected to the bus. That has no components on it: all it does is connect the modules together. System that various modules can be plugged into.
It nominally has 8K ROM, 32K RAM, runs at 7.3728MHz and communicates overīeing a "modular" computer means that the RC2014 uses a backplane It is not a clone of anything specific,īut there are suggestions of the ZX81, UK101, S100, Superboard II and Apple I in It is inspired by the home built computers of the late 70sĪnd computer revolution of the early 80s. RC2014 is a simple 8 bit Z80 based modular computer originally built I understand that 2014 is the year it was designed, and "RC" stands for "retro computer". It is a simple computer sold in kit form, and using a Zilog Z80 CPU.
James Stanley The RC2014 Z80 Microcomputer