lezanderson Posted March 27, 2015 Share Posted March 27, 2015 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 CPUTIM9904A Clock genTMS9901 PIO x 2TMS9902 SIO x2EPM7128SLC84 as Glue logic (possibly 2pcs)RAM 128kx8bit x 4 pcs (512k sram 100ns or faster)NVSRAM (DS1245 128kx8bit 2pcs) 256k 70 or 100nsROM V9958 Video 192K Video RAM PAL/NTSC RGB & Composite outputSN76489 sound 2pc (Left / Right sound output)SAA1099 Sound PSGPS/2 keyboard/ Mouse8255 for CF Card reader8255 for PATA IDE interfaceRTC Real Time clockAM9511A 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) !! 3 Quote Link to comment Share on other sites More sharing options...
Astharot Posted March 27, 2015 Share Posted March 27, 2015 Your project seem a Geneve console.. how software your idea is taken Geneve S.O. or you think a all new system? Or think how interface ti99 cartdrige for have basic e/a etc etc?? Quote Link to comment Share on other sites More sharing options...
rhcocker Posted March 27, 2015 Share Posted March 27, 2015 I don't know how feasible it is, but I want one. Quote Link to comment Share on other sites More sharing options...
gregallenwarner Posted March 27, 2015 Share Posted March 27, 2015 If you're going to use a PLD, why not go for the equally priced, but much more capable MAX10, and program the entire system in there, CPU and all? With today's FPGA's a SoC solution is the best way to go for something like this. Plus, the new MAX10's have built-in user flash and SRAM, so the console ROM's and main memory could also be located on-chip. Fewer chips equals cost savings. Quote Link to comment Share on other sites More sharing options...
lezanderson Posted March 27, 2015 Author Share Posted March 27, 2015 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 eachTIM9904A Clock gen $2.5 eachTMS9901 PIO x 2 $2.0 eachTMS9902 SIO x2 $2.0 eachEPM7128SLC84 as Glue logic (possibly 2pcs) $2.0 eachRAM 128kx8bit x 4 pcs (512k sram 100ns or faster) <$1.0 each NVSRAM (DS1245 128kx8bit 2pcs) 256k 70 or 100ns $2.0 eachROM about $1.0 each or lessV9958 Video 192K Video RAM PAL/NTSC RGB & Composite output <$5.50 eachSN76489 sound 2pc (Left / Right sound output) $0.50 eachSAA1099 Sound PSG $1.50 eachPS/2 keyboard/ Mouse (use a cheap micro-controller <$1.0)8255 for CF Card reader $1.5 each8255 for PATA IDE interface $1.50 eachRTC 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 ! Quote Link to comment Share on other sites More sharing options...
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