When designing with programmable logic, you usually have to revert to the simulator. The CPLD implementation inverts its 3.5MHz CPU clock output, as the ZX Spectrum will invert it back to its proper phase with a transistor driver before passing it to the Z80. The same clone, now using a proper RGB output. A few weeks ago I finished the Harlequin Dynamic Memory interface. The first test has been to generate a stable television frame to prove that the CPLD is clocking correctly. It suffered from a buggy I/O contention model which made I/O reads, particularly keyboard reads from machine code, unreliable, hence the addition of the ‘cockroach’ mod (basically a 74LS00 chip hand soldered on top of the PCB with flying lead connections, later contained on its own mini daughterboard). Chris designed a ZX Spectrum clon, the "Harlequin". I still The heart of the ZX Spectrum series of computers is a custom chip called the ULA (Uncommitted Logic Array). It fixes the initial I/O contention issue, but unfortunately it was found that the resulting I/O contention was overly aggresive, contending ports that did not need to be. See this link for more details. ULAplus is a plug-in replacement ULA for the ZX Spectrum which increases the total palette to 260 colours. The aim of the site is to allow the renewal of retro computers, whilst not making a huge profit. A. 5C102E – Issue 1 and 2 PCB’s (requires cockroach mod). The CPLD version of this implementation is aimed to serve as replacement for that clone. For this to be showed correctly, both interrupt timmings and ULA timmings have to be perfect. At the end of the day, we’re just hobbyists). Whether you want to just get a faulty Spectrum 128K back up and running, or want to preserve that precious Toastrack ULA, then the vLA128 is exactly what you need. Philippines again?” 8448 Ferranti ULA 6C001E-7 This site uses cookies to enhance your browsing experience. Timex Hicolor mode supported in the FPGA version of the core. Bottom view of above design. The following programs ran and behaved the same as with a normal ULA chip: Fusetest, Ulatest3, FloatSpy, IR Contention, BTime, STime, Shock Megademo, Aquaplane, Darkstar, Sidewize, Vectron, Arkanoid, (and many other games..), A. It’s not really an acronym – it’s just a nice word that has ULA in it :). The vLA81 is a modern plugin replacement for the ZX81 ULA. Sinclair ZX Spectrum. Usually available on sellmyretro.com (search for seller zaxon, keywords SLAM 128 ULA). In most cases the existing socket will be OK (unless, of course, the existing ULA is soldered in). Testing the Timex hicolor mode on a ZX Spectrum ULA enhanced clone. Once proof copies have been checked, distribution will begin! NOTE: only the hicolor mode is supported. The quintessentially British home computer is now 30+ years old and most will have been through some rough treatment (and then left in the loft for decades!). Nebula Spectrum ULA Chip Replacement Module The Nebula is a Spectrum 48 daughterboard, designed to replace the ULA chip found in UK Spectrum motherboards (versions 2 to 6). OpenCores®, registered trademark. It was on a Issue 4 S Board. Yet to be tested against a real Z80 for timming accuracy (tv80 core seems not to have exact timmings, but this could be my fault, not tv80's). Q. This project is mostly based upon the work of Chris Smith. The mod was performed with a single diode and resistor on early Issue 2 machines. Part II. Chris’ blog containing a description of his journey reverse engineering ULA functionality can be found here. All timmings according to Chris Smith's specs. A. Aquaplane, showing a perfect full screen horizon). The module’s video output is the same as that provided by the original ULA (IE: YUV to drive the Spectrum’s modulator circuit. This was required to test the dynamic ram timing reverse-engineered from the ULA. If some of the nearby logic chips (IC3, IC4, IC24, IC25) are in sockets they may cause tension in the case when re-assembling. The ULAplus specification describes an enhanced ULA for the ZX Spectrum. Usually available on sellmyretro.com (search for seller zaxon, keywords SLAM 128 ULA). They will be available from store.retroleum.co.uk (under Spectrum Chips) but please bear in mind they are hand made which is very time consuming and so supplies will be limited. Will it work on [insert freaky foreign Spectrum clone here] ? The Nebula is based on a programmable logic chip with some external components to handle the analogue systems. The hires mode or the dual screen mode of the Timex TC2048/2068 is not supported. Follow me on Twitter < 65 of 68 > The ULA Replacement Mar 28, 2008. This is a replacement for the ULA in the Sinclair ZX Spectrum 128 toastrack and Sinclair ZX Spectrum+2 (grey case). SLAM128 Price: £ 19.99 Add to cart. A ZX Spectrum clone built on top of the Gameduino shield by Don "Superfo". ULA+ implemented in the FPGA version of the core. Ability to map ram to the ROM space (write protect enable/disable – 32K internal ram required). Twitter . It’s is strongly advised that these chips are soldered directly to the spectrum PCB. In most cases the existing socket will be OK. Many thanks to Chris Smith for his excellent book: “The ZX Spectrum ULA – How to design a microcomputer” without which the module could not have been made. This resulted in the implementation of the ‘spider’ mod, a ZTX313 transistor soldered over the CPU (or next to the upper RAM IC’s in some models). © copyright 1999-2018 OpenCores.org, equivalent to Oliscience, all rights reserved. As they simply don’t make Spectrum 128K ULAs anymore, then unfortunately if the ULA has failed, then options for repair are diminishing. RFC: ULA Replacement for ZX Spectrum SE Showing 1-43 of 43 messages. The Gameduino has footprints to solder either a 512KB SRAM memory, or a 32MB SDRAM. Narrow IC pins for easy plugin ULA replacement. A new enhanced ULA description which supports this mode has been uploaded to the fpga_version directory. It is one of several ULA replacements Charlie has made for members of the Sinclair computer family including the vLA81 for the ZX81, the vLA82 for the Spectrum 48K and the vLA1 for the Sinclair ZX Interface 1. These are exclusively found in late Issue 2 machines and have date codes between 8320 and 8324. Follow me on Twitter < 68 of 68 ULA Replacement … A guide showing the external configuration switch option can be found here. Closeup of the wiring needed to adapt the digital IRGB signals to analog RGB signals. Dark Star. 6C001E-5 ULA Nebula Spectrum ULA Chip Replacement Module The Nebula is a Spectrum 48 daughterboard, designed to replace the ULA chip found in UK Spectrum motherboards (versions 2 to 6). The +2A and +3 both use the same 40077 gate array. This game features a graphic drawn in the border area. RFC: ULA Replacement for ZX Spectrum SE: Andrew Owen: 5/15/00 12:00 AM: Those who have been following my posts over the last few months will know that I have been slaving away on a new ROM set for the Spectrum. Any plans for similar devices for other machines? It is one of several ULA replacements Charlie has made for members of the Sinclair computer family including the vLA81 for the ZX81, the vLA82 for the Spectrum 48K and the vLA1 for the Sinclair ZX Interface 1. The ULA implementation follows, where possible, the original ULA timmings, as stated in "The ZX Spectrum ULA: how to design a microcomputer", written by Chris Smith and published by ZX Design and Media, ISBN 978-0-9565071-0-5 For other ULA revisions, the following holds: Other combinations may work (I have seen a 5C112E ULA work in an Issue 6A with no problems), but the above is what was officially documented and supported in the service manual. This scheme is the same as shown at the Paul Farrow site. This was required to test the dynamic ram … This project is mostly based upon the work of Chris Smith. It is designed for maximum compatibility with existing software.
The Unit'', Army,
Carver Skateboards,
Feeling Minnesota 123movies,
Mexican Night Snake For Sale,
Rozalia Russian Charity Fun Run,
Why Do Crows Attack Herons,
Matthew Beard Interview,
Brown Bear, Brown Bear What Do You See Powerpoint,