| Electronics > Beginners |
| modern TTL/Logic-gate/74xx |
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| rstofer:
I liked the older Spartan 3 Starter Board with 3 ea 50 pin edge connectors. I used one connector for a logic analyzer interface (32 channels) and the one on the right for a Compact Flash board. That LA is the only way I ever got the system to work. The Vivado ILA will do it even better! https://store.digilentinc.com/spartan-3-board-retired/ I eventually migrated my IBM 1130 to a Nexys 2 board. It's very expensive for what it is but at least it had an edge connector for the Compact Flash board (and a 4 channel FTDI UART<->USB board). This was back when the Nexys 2 was the top of the line... https://store.digilentinc.com/nexys-2-spartan-3e-fpga-trainer-board-retired-see-nexys-4-ddr/ https://www.digikey.com/product-detail/en/ftdi-future-technology-devices-international-ltd/FT4232H-MINI-MODULE/768-1031-ND/2027253 I built a logic analyzer out of the small version of the Starter Board: https://www.sump.org/projects/analyzer/ PacMan is built on another Nexys 2 board just because I had it sitting around. The T80 core (Z80) at OpenCores.org is excellent for retro arcade games (that used a Z80) and for running CP/M on a Compact Flash. https://opencores.org/projects/t80 There are 6502 cores at OpenCores.org Among others: https://opencores.org/projects/cpu6502_true_cycle |
| james_s:
--- Quote from: ker2x on October 09, 2019, 06:10:21 am ---This is the first time i try an "hardware first" project on my own. Before drawing any schematic i needed to know what was available (without doing any dumpster diving to recycle old 74xx chips). The problem of 74xx availability have been solved (74HC chips from On Semiconductor), they're not the cheapest option but they exist. --- End quote --- It's because they're a niche specialty part today, AVR microcontrollers are sold by the many millions, 74xx parts are probably at least an order of magnitude smaller market. |
| rstofer:
That Gadgetory site has a lot of component kits for the tutorials by PyroEDU http://www.pyroelectro.com/edu/ https://gadgetory.com/index.php?route=product/category&path=66 This might be a very acceptable learning program which, by being more up to date, is somewhat easier to approach. There are lab examples using the component kits from Gadgetory along with DVDs for each of the major sections (I don't know if they are just duplicates of the YouTube videos). I have only watched about 1-1/2 videos but I'm reasonably impressed. A beginner would be a long way down the path after completing this series. Lab examples are probably the best way to learn electronics. I'm going to spend a bit more time on this site! |
| jmelson:
--- Quote from: ker2x on October 07, 2019, 05:09:15 pm --- Thanks to my painful experience with FPGA i have a rough idea of the importance and difficulty of timing. --- End quote --- Well, I don't do "cutting edge" projects where I need to get every last ns out of an FPGA. On the other hand, I did do a project where we had a bunch of 32-bit counters running at 150 MHz on a Spartan 3AN FPGA, which is a pretty old part. No problem whatsoever getting that to compile and work. So, any place I need about 3 - 10 TTL chips worth of stuff, I use either a 9500XL or CoolRunner II CPLD from Xilinx, for about $1 - 2 each. For more than about 10 TTL chips equivalent, I use a small Spartan 3A for about $13. Basically, if it simulates, it works, period! And, if it doesn't simulate, it is because I am lousy at writing VHDL. Jon |
| rstofer:
Whether an HDL or a procedural language, the only way to really get a handle on it is to write it. This book (free) will help: http://freerangefactory.org/pdf/df344hdh4h8kjfh3500ft2/free_range_vhdl.pdf Page 93 is where the Finite State Machine coding really starts. Note where the author pre-assigns the output. Page 95, first bullet, explains why. This is a CRITICAL concept! |
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