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| Learning the Art of Electronics - keypad |
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| David1:
Has anyone found ordering information or the schematic referred to on Page 620 of Learning the Art of Electronics? Page 620 of LAoE says, "The keypad is not a standard commercial part. See Appendix E for ordering information and Appendix 14N.20 for the schematic, in case you want to build your own." However, Appendix E doesn't mention the keypad. The digital parts list on the LAoE website (link below) says, "See LAoE website" but there the trail goes cold; the website gives details for ordering the LCD but not the keypad (as far as I can see). Also, Appendix 14N.20 doesn't seem to exist, nor the schematic for the keypad. So the questions are: * Has anyone found ordering information for the LAoE keypad? * Has anyone found Appendix 14N.20 or the schematic for the keypad? * Can anyone suggest an alternative approach to providing the keypad functionality which includes: controlling lines D4 to D14 of an XC9572XL counter; and writing 8 bit values to RAM via a 74HC541 octal 3-state buffer. https://learningtheartofelectronics.com/parts-lists/parts-lists/ |
| rstofer:
There was another thread on this last week: https://www.eevblog.com/forum/projects/has-anyone-built-the-dallas-breadboard-computer-from-art-of-electronics/msg1503499/#msg1503499 For the price, I am betting that the display comes with whatever is needed including the keypad. Just to make things difficult, the project uses a PAL device (Programmable Array Logic) which will be problematic for a newcomer. These need to be programmed and many take a special device to do the programming. Later on, the digital section settles down to basically a course on the 8051 chip which is archaic but still used. I might consider looking through the sections and seeing if a commercial 8051 trainer wouldn't work just as well. https://www.ebay.com/itm/8051-Microcontroller-Kit/282939936088?hash=item41e088cd58:g:SjwAAOSwXeJXeMWT Note that I haven't read through that section of the manual so I have no idea what is going to be presented. But scanning through the next 50 pages or so, they use that keyboard/display a lot. There are so many other ways to learn about digital systems, I think, personally, I would give theirs a pass. Or, I would buy or reinvent their display/keyboard and then try to figure out what the Dallas "Big Board" brought to the dance. Or, if I really wanted to learn about computer design down in the dirt with the flops and gates, I would Google for the LC3 project. This presents an entire RISC processor design from scratch. The project comes with an assembler and C compiler so it may be useful upon completion. It will be a modest project in terms of FPGAs but a major step along the educational path. There is a book: https://www.amazon.com/Introduction-Computing-Systems-Gates-Beyond/dp/0072467509/ref=sr_1_1 |
| rstofer:
Don't overlook Ben Eater's 8 bit computer built on a bunch of prototype boards. It is a VERY approachable project. Note that page 620 makes reference to the idea of 'buses'. Ben's project does things in a very similar way - he has some prototype boards down the middle of the project for the bus. There is an entire video series on this project and I binge watched them last week. It's an amazing project build with discrete logic. No, the architecture won't be challenging anything we use today but it's done with fairly discrete logic so that counts for something. This is far more approachable than the LC3 project for newcomers. I would do Ben's project and skip the LTAOE stuff altogether until they get to the 8051 and then I would consider the trainer I linked above. Or not... Ben's project has a lot of education left in it. Hint: Don't buy the cheapest prototype boards you can find. Figure to pay about $8 each, maybe a bit more. Get them from Amazon as Ben recommends. You simply do not want to chase bad connections in a project like this. |
| bd139:
Dump this part of the book's requirements entirely and buy an AVR / ARM / PIC dev board and follow the general concepts rather than the board and processor specifics. It's a bit archaic to be honest. rstofer's suggestion is a damn good one. But when you need to learn about integration and peripherals and become productive, there's nothing like a real uC to play with. |
| rstofer:
--- Quote from: bd139 on May 05, 2018, 10:29:21 pm ---Dump this part of the book's requirements entirely and buy an AVR / ARM / PIC dev board and follow the general concepts rather than the board and processor specifics. It's a bit archaic to be honest. rstofer's suggestion is a damn good one. But when you need to learn about integration and peripherals and become productive, there's nothing like a real uC to play with. --- End quote --- I thought there would be great benefit in knowing CPUs at the dirt level. That's the way it was taught when I was in school but the micro hadn't been invented. Knowing the nitty gritty may be quite helpful but clearly Ben Eater's computer isn't going to set the world on fire with only 16 byte of RAM. But it's a start! The beauty of the project is Ben's videos. There's an enormous education in those tutorials. Then move on to one of the ARM chips (or take an intermediate step through the Arduino arena) and move into the modern era. There will be no disadvantage to knowing exactly how CPUs work but all of a sudden, the work morphs into programming. The more I watch Ben's videos, the closer I get to building the thing. Just because... A more realistic computer which could be built using the same concepts is BLUE , a 16 bit computer with 4k of RAM. This computer is described in Caxton C Foster's "Computer Architecture" https://www.alibris.com/Computer-Architecture-Caxton-C-Foster/book/1255656 As described in the book, this computer is similar to one that might cost $5k back in the very early '70s. |
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