Summary of Contents for Donn Steward CPUville 8-bit
- Page 1 CPUville 8-bit Processor Register Display Kit Instruction Manual By Donn Stewart © 2019 by Donn Stewart If you find any errors in this manual, please let me know. Thanks.
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Page 2: Table Of Contents
Table of Contents Introduction..............................3 Building Tips..............................3 Building the Register Display........................8 Testing and Using the Register Display....................12 Register Display Schematic........................13 Register Display Parts Organizer......................14 Register Display Parts List........................14... -
Page 3: Introduction
Introduction Building Tips Thanks for buying a CPUville kit. Here is what you need to build it: 1. Soldering iron. I strongly recommend a pencil-tip type of iron, from 15 to 30 watts. 2. Solder. Use rosin core solder. Lead-free or lead-containing solders are fine. I have been using Radio Shack Standard Rosin Core Solder, 60/40, 0.032 in diameter. - Page 4 This is only about 1/8 inch of the 0.032 inch diameter solder that I use. If you keep applying the solder, it will drip down the lead to the other side of the board, and you can get shorts. Plus, it looks bad. 4.
- Page 5 If this happens, you have to remove the solder with a desoldering tool, and re-do the joints. Other tips: 1. Be careful not to damage the traces on the board. They are very thin copper films, just under a thin plastic layer of solder mask (the green stuff). If you plop the board down on a hard surface that has hard debris on it (like ICs, screws etc.) it is easy to cut a trace.
- Page 6 4. You might have to bend the leads on components, ICs or IC sockets to get them to fit into the holes on the boards. For an IC, place the part on the table and bend the leads all at once, like this: Bending the leads one-by-one or all together with the needle nose pliers doesn't work as well for some reason.
- Page 7 5. After you have soldered a row or two check the joints with a magnifying glass. These kits have small leads and pads, and it can be hard to see if you got the solder on correctly by naked eye. You can miss tiny hair-like solder bridges unless you inspect carefully. It is good to brush off the bottom of the board from time to time with something like a dry paintbrush or toothbrush, to get off any small solder drops that are sitting there.
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Page 8: Building The Register Display
Building the Register Display Print out the Parts Organizer (page 14) and put the parts on the organizer to make sure you have them all, and to get familiar with them:... - Page 9 Once you have checked the parts you can start to solder them onto the circuit board. The easiest way to solder the components is to start with the shortest (parts that lie closest to the board) and proceed to the tallest. The order is resistors, pushbutton switches, LEDs, IC sockets, capacitors, 4- position DIP switch, 50-pin connector.
- Page 10 Here is a little trick for getting a long row of LEDs to line up nicely, that is, to stand up straight. The bottom of the LED base is flat, so go down a row, soldering only one lead of each LED while pressing down on the board.
- Page 11 6. The 4-position DIP switch is soldered so ON is up (toward the rear of the board). 7. The 16-pin header receptacle is soldered on the back of the circuit board: 8. Once you have finished soldering all the parts on the computer, inspect the board to make sure there are no solder bridges or unsoldered pins.
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Page 12: Testing And Using The Register Display
Testing and Using the Register Display Plug the ICs into the sockets, being careful not to bend under any pins. A bent-under pin can look like a properly inserted pin from the top. The register display can be tested by putting +5V and ground onto pins 1 and 50 of the display connector, respectively. -
Page 13: Register Display Schematic
Register Display Schematic The register display is simple. The register outputs and processor flags are brought to the inputs of the 74LS240 inverting buffers from the main board through the display connector. The state and system clock signals are brought in from the control board through the 16-pin front panel connector. The LEDs are connected to the buffer outputs so that the buffer “sinks”... -
Page 14: Register Display Parts Organizer
Register Display Parts Organizer Capacitor, 0.01 uF 50-pin header 74LS240 inverting buffer 16-pin header receptacle 470-ohm resistor Red LED Pushbutton 4-position DIP switch Yellow-Violet-Brown 20-pin DIP socket Register Display Parts List I buy almost all my parts from Jameco. If you buy from a different supplier, you can check the datasheets for these parts on the Jameco website by referring to the part number.
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