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lezanderson

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Posts posted by lezanderson

  1. Posted

    Old ICs (TMS99xx)

     

    I've bought quite a lot of old ICs from various sources, though mainly from China, and found on the whole about 85% are fine, some are wrongly labelled, probably due to the original makings being to faint to read. Some are DUFF probably due to bad handling and not using Anti-Static precautions etc. Though you've got to remember these ICs can date back to the Mid 70s , so even NOS (New Old Stock) from say 1976 could be faulty..having not been used for some 40 years ! So TEST them once they've arrived No good getting ICs and not testing them for six month as then it's too late to complain !

     

    Also if your buying multiple ICs ask for a Discount as if your buying DIRECT you can avoid paying ebay fees as long as you trust the supplier you'll be OK. It's also best to avoid the extremely (Silly) priced ICs , ones for $100 etc you see. Someone is just seeing if there's anybody stupid enough to buy them...the old saying 'There's one born Every Minute' pops to mind !

  2. Posted

    something like this :

     

    Z80 CPU

    Cartridge Slot (32K Cart as original)

    8K SRAM

    8K SRAM

    8K SRAM

    8K EPROM

    74HC138 + 74HC139 Memory decoders,

    (24K SRAM + 8K OS ROM)

    GAL22V10 I/O decoder

    V9958 VDP

    TMS4464-10 DRAMs 4 or 6pcs

    CXA1645 or CXA1145 PAL/NTSC Encoder

    SN764789 + AY-3-8910 PSGs

    8255 for CF card reader

    etc

    There's already similar things being developed on other sites..so it shouldn't be too hard to knock a prototype out ?

    This is most certainly feasible and achievable at a sensible price :

     

    Z80 CPU (Z84C0006PEC) $1.65 or so

    Cartridge Slot (32K Cart as original) a couple of Dollars ?

    8K SRAM <$.080 each

    8K SRAM <$.080 each

    8K SRAM <$.080 each

    8K EPROM <1.0 each

    74HC138 + 74HC139 Memory decoders, < $0.50 each or less

    (24K SRAM + 8K OS ROM)

    GAL22V10 I/O decoder $1.0 each

    V9958 VDP $7.0 or so each

    TMS4464-10 DRAMs 4 or 6pcs $0.75 each

    CXA1645 or CXA1145 PAL/NTSC Encoder $1.50 each or less

    SN764789 + AY-3-8910 PSGs $0.50 / $1.40 each

    8255 for CF card reader 82C55 <$2.0 each

    etc

    All the ICs should only cost about $22 or so, then IC sockets , Connectors, Cartridge slot etc plus a low cost PCB should be doable for :

    ICs $22

    Connectors etc $15

    PCB $32 ( Rough Guess)

    So it is possible to make a low cost CV 2 ?? It's just design/making/testing etc that's the difficult but !!

  3. Posted

    A kick-Starter project is unlikely to succeed as there's not enough real interest to get it off the ground. The only serious way ahead is probably to get a team of like minded people together and make a prototype in their spare time .This wouldn't be a FLASHBACK type console put something you'd get as a kit (using legacy ICs) and make yourself and that is al limited market.

     

    There's been / are other projects namely the Colecovision 2 (NEO) but that seems to be a complete MYTH and will probably never happen ??

  4. Posted

    I've done costings for a similar type of thing you may find helpful (or not):

     

    Rough guide to costing !

     

    Z84C0008PEC Z80 CPU DIP40 $2.0 each

    UM61512 64K SRAM narrow DIP32 $1.50 each or so

    HM61256 32K SRAM DIP28 <$1.0 each

    M27C64 8K EPROM <$1.0 each

    W27C512 EEPROM (DIP/PLCC) <$1.0 each

    EPM7128SLC CPLD 64 I/O lines $2.0 each

    V9958 VDP $7.0 each

    D41464x-10 DIP $0.75 each

    CXA1645/1145 PAL/NTSC encoder $1.45 each

    SN76489 PSG Sound Chip $0.50 each

    AY-3-8910 PSG MSX $1.40 each

    8255 PIO about $1.80 each

    ATmega88 MCU $1.0 each

    AT89C2051 MCU <$1.0 each

     

     

    Optional :

     

    RTC (DS12C887) $2.0 each

    Z84C9008VSC Z80 CTC,PIO,SIO $2.0 each

    AM9511 Maths Co processor $2.50 each

     

    these prices where quoted by funkward-tech as I've got these ICs before from them.

     

     

    Obviously you could by from mouser,Digikey etc, but you'd pay about five times as much, it all depends on how you feel about getting ICs from China.

    ----

  5. Posted

    Spotted this on ebay.com

     

    http://www.ebay.com/itm/Zilog-Z80-Colecovision-Kit-8MHz-Z80-MSX-Homebrew-/151686369904?pt=LH_DefaultDomain_0&hash=item2351365270

     

    Bought stuff from them before and they are OK to deal with, though stuff from China takes forever to arrive !

    I've bought stuff from funkward-tech , G&C Supermarket and a few other Chinese Suppliers, on the whole I had no problems, obviously with some of the ICs being pulls watch out for the odd DUFF IC, I got a few faulty ICs, they where replaced for free.. so check the ICs as soon as they arrive if possible.

     

    The Cheap Z84C0020PECs on ebay.com are 'Remarked/labelled' old NMOS Z80s (Z80A,Z80B,Z80H) so be aware of that. I got some (10pcs) and found 80% worked fine at 4MHz+ some even worked at 16MHz but they where NOT 20MHz Z84C0020s !

  6. Posted

    The problem is cost.. in a perfect world you could use an F18A ($75,£50 each !) or a V9990 plus all the other bits and bobs but then the complexity and cost would spiral out of control...a bit like the Homer Simpson car that cost $87,000 and nobody wanted to buy ! A V9990 could be an option but I'm not sure that it's 100% backward compatible and it's surface mount?

     

    However the V9958 is quite a big leap from the old TMS9918/29 plus having two sound chips SN76489+AY-3-8910 is quite a big step from the original while still being cheap to make. And there's already a working V9958 board with schematics available.

  7. Posted

    Going it alone or even as a team is probably a good option.. as I've already done draft costings. The initial breadboarding will be using DIP ICs whereas the final units would be PLCC as these are NOS and cheaper than DIP to keep costs down, plus I know the Z84C0020VEC can easily be over-clocked to 28.64MHz with no ill effects. All the glue logic, memory & I/O decoding would be done by the EPM7128.

     

    Z84C0020VEC PLCC $2.0 each (or less)
    Z84C9008VEC (optional?) $2.0 each
    64K SRAM UM61512 <1.50 each
    64K EEPROM W27C512 PLCC $1.0 each
    EPM7128SLC84 Glue logic RAMN/ROM select $2.0 each
    V9958 Video / scart/phono output (V9958+DRAMs+CXA1145=$12)
    SN76489 Sound + YM2149 $2.0
    Two Joystick ports (Atari Type)
    Two original type controller ports
    Z80 BUS out for daughter-board
    Cartridge Slot for original Carts
    RS232 Com1 Com2 ?? Ports
    Parallel output port ?
    PS/2 Keyboard input

    ** The ICs should cost about $25, + PCB + connectors , total for motherboard <£50

    Daughter Board:would contain
    Real time Clock RTC $2.50
    CF card reader
    PATA/IDE laptop hard-drive
    Maths AM9511 FPU ? $2.50

    The daughter board sold as an upgrade would cost, to make, £30 and sell for £60

    Obviously this is still in the VERY early stages but it is possible.

  8. Posted

    Does anyone know anything about Crowd Funding a project ?? I've been toying with the idea for some time but find it rather perplexing !

     

    But as I'm new to this I thought I'd ask around for some advice.

     

    *********

     

    After looking at the ZX Spectrum projects that have been Crowd funded, I thought to myself.... is it worth a try ?? So I was thinking of doing some Crowd-Funding for a New Super Colecovision Console... nothing like them Naff Flashback stuff...but with real hardware.

    Z84C0020VEC PLCC
    Z84C9012VEC (optional?)
    64K SRAM UM61512
    64K EEPROM W27C512 PLCC
    EPM7128SLC84 Glue logic RAMN/ROM select
    V9958 Video / scart/phono output
    SN76489 Sound + YM2149
    Two Joystick ports (Atari Type)
    Two original type controller ports
    Z80 BUS out for daughter-board
    Cartridge Slot for original Carts
    RS232 Com1 Com2 ?? Ports
    Parallel output port ?
    PS/2 Keyboard input


    Daughter Board:would contain
    Real time Clock RTC
    CF card reader
    PATA/IDE laptop harddrive
    Maths AM9511 FPU ?



    come either as pre-built or a kit . Running at either 3.58MHz or 28.64MHz (turbo mode)

    About 18 months ago I asked around for prices on a Z80 system (basically a MTX plus) and was quoted between £7000-£10000 to design and built prototype hardware by three companies. So the Colecovsion could be cheaper ?

    The idea would be to make it for <£50 and sell for £99+shipping which are realistic and achievable prices.


    Any ideas about the best way to do it...then let me know. This Crowd Funding thing is probably harder than it looks !

    Well it's got to be worth a try !

    • Like 1

  10. Posted

    The Two CPLD's I'd consider for glue logic are the : EPM7128SLC84 and the EPM7032SLC44, 128 & 32 Macrocells respectively both can be got for $2.0 each .. much cheaper than an FPGA IC. They can also be programmed in situ with a low cost MAX Blaster programmer about $7.0 each ?

     

    A rough 'DRAFT' breakdown of cost for ICs

     

    TMS9900 CPU $2.50 each
    TIM9904A Clock gen $2.5 each
    TMS9901 PIO x 2 $2.0 each
    TMS9902 SIO x2 $2.0 each
    EPM7128SLC84 as Glue logic (possibly 2pcs) $2.0 each
    RAM 128kx8bit x 4 pcs (512k sram 100ns or faster) <$1.0 each
    NVSRAM (DS1245 128kx8bit 2pcs) 256k 70 or 100ns $2.0 each
    ROM about $1.0 each or less
    V9958 Video 192K Video RAM PAL/NTSC RGB & Composite output <$5.50 each
    SN76489 sound 2pc (Left / Right sound output) $0.50 each
    SAA1099 Sound PSG $1.50 each
    PS/2 keyboard/ Mouse (use a cheap micro-controller <$1.0)
    8255 for CF Card reader $1.5 each
    8255 for PATA IDE interface $1.50 each
    RTC Real Time clock $2.50 each DS12C887 ??
    AM9511A 4MHz Maths co-processor $2.50 each

     

    Most of the Chips would be Working Pulls and some NOS !

  11. Posted

    I was thinking of doing a Feasibility Study on a New TMS9900 (TiI99/4A) Type system. Possibly with the following spec:

    Looking at the possibility of making a replacement (low cost) Ti/99/4a motherboard ??

     

     

    TMS9900 CPU clocked at 16/4MHz 16MHz input 4MHz bus, Zero wait states on RAM/ROM

     

     

    TMS9900 CPU
    TIM9904A Clock gen
    TMS9901 PIO x 2
    TMS9902 SIO x2
    EPM7128SLC84 as Glue logic (possibly 2pcs)
    RAM 128kx8bit x 4 pcs (512k sram 100ns or faster)
    NVSRAM (DS1245 128kx8bit 2pcs) 256k 70 or 100ns
    ROM
    V9958 Video 192K Video RAM PAL/NTSC RGB & Composite output
    SN76489 sound 2pc (Left / Right sound output)
    SAA1099 Sound PSG
    PS/2 keyboard/ Mouse
    8255 for CF Card reader
    8255 for PATA IDE interface
    RTC Real Time clock
    AM9511A 4MHz Maths co-processor

    cost for the ICs about $40 (£28)

    If it could be squeezed onto a double sided PCB (300mm x 160mm or so) then the PCB should only cost about £15

    Connector,buttons,switches,IC sockets etc about $10 , £7

    So total cost would be about £50, $75 ??

    As all the ICs are still readily available it shouldn't be to difficult to source everything !

     

    The Hard part is obviously design/testing it, and programming the CPLD (VHDL/Verilog) !!

     

    • Like 3

  13. Posted · Edited by lezanderson

    Some of you may of noticed that I was selling Z80 kits on ebay for those interested in tinkering with electronics and microcomputer design.

     

    I've talked Funkward-tech into selling these kits, and bespoke customs kits on ebay.com. (As i've stopped selling them !)

     

    You can either buy from their website or buy direct and get wholesale prices just contact them if your interested..

     

    Some important things when buying from China..

     

    If buying direct, tell them your TARGET price ... the price you want to pay
    Check ICs as soon as they arrive.. They will send replacements if any are DUFF.
    Tell them to use static Sensitive precautions as they may not.
    don't let them 'Overcharge you' !

     

    ******************************************

    Below is a rough guide to the prcies I paid for some ICs, this may be useful when costing a project ?

     

    Approximate wholeslae price for some common ICs

     

    Wholesale prices:

     

     

    CPUs

    Z84C0010PECs/Z84C0008PECs etc $2.0 each DIP40
    Z84C0020VEC $2.0 each PLCC44
    HD64180 $3.50 each DIP64 / PLCC
    Z8S18033 PLCC68 $3.50 each

     

    Static RAMs (DIP)

    HY6264 8Kx8bit 70ns/100ns $1.0 each
    HY62256 32Kx8bit 70ns/100ns $1.0each
    HM628128/TC551001/KM68000 128Kx8bit 55ns/70ns/100ns $1.0 each
    KM684000/HM628512/K6T4008 512Kx8bit Static RAM 70/55ns $3.50 each

     

    Static RAM (SDIP)

    UM61256 15ns DIP <$1.50 each
    UM61512 15ns DIP <1.50 each

    NVSRAM (DIP) : DS1250/DS1245 etc
    32Kx8bit / 128Kx8bit /512Kx8bit $2.0 each

     

    EPROMs/EEPROMs

    27C32 DIP <1.0 each 120/100ns
    27C64 DIP <1.0 each 70/120/100ns
    27C128 DIP <1.0 each 70/120/100ns
    27C256 DIP <1.0 each 70/120/100ns

    (DIP & PLCC)
    W27C512 64Kx8bit 45ns DIP/PLCC $1.0 each
    W27C010 128Kx8bit 70ns DIP/PLCC $1.0 each
    W27C020 256kx8bit 70ns DIP/PLCC $1.0 each
    29F040 512kx8bit DIP/PLCC $3.50 each PLCC $1.0 each

     

    Video Processors

    V9958 DIP64 <$5.0 each
    D72020/D7220 DIP40 $2.0 each
    V6366 PLCC68 $3.50 each
    EF936x GDP DIP40 <$15.0 each
    R6545 DIP40 $2.0 each
    V9990 Surface Mount <$20.0 each

    TMS4465/D41464 100ns DRAMs $0.75 each

     

    Sound Chips

    SN76489 DIP16 $0.50 each
    SAA1099 DIP18 <$1.50 each
    AY-3-8910 DIP40 <$2.0 each
    YM2149 DIP $2.50 each
    YM3812 DIP $1.50 each

     

    PIO
    8255 PIO DIP40PLCC44 $2.0 each : PLCC44 ones $1.0 each

     

    RTC (Real Time Clock)

    DS12C887 or DS12887 DIP RTC $2.50 each

     

    Maths Co processor

    AM9511 DIP Maths Scientific calculator on a chip ! $2.50 each

     

    MCUs

    AT89C205 DIP $0.75 each
    ATMega88 DIP $1.50 each

     

    GALs/CPLDs

    GAL22V10/GAL16V8 etc $1.0 each
    EPM7128SLC84 $2.0 each
    EPM7160SLC84 $10.0 each
    EPM7064SLC4 ask ?

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