GND and VCC are perpendicular to the rest of the pins in the circuit diagrams, whereas the real Z80 is a DIP with no pins at all in these locations. I find that this makes the circuit diagram harder to read. I have to map between the real physical pins and the pins in the diagram. In regard to your second question. When we draw symbols for processors on schematics
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we often rearrange the pins to make the schematic easy to draw and read. You will soon get used to it. Those 470 ohm resistors place a hex 0x00 on the data lines so that the uP always executes a `NOP` instruction. They arent needed if you later connect an EPROM to the data and address lines, which you will have to do at some point. A good memory mapping technique for a small computer (very small) like this is to use A15 for the RAM/ROM select bit. When A15 is low (a `0`) it selects ROM, and when high (a `1`) it selects RAM. This maps into 32k of ROM and 32k of RAM but you can use less of each and still use that bit. Once you get some code running in ROM you`ll be able to program service calls for various devices like keypads and LEDs and whatever else you want to drive with it like relays, etc. You might find it easiest to interface with a Serial type LCD display rather than an actual monitor at first, as any display type you use should have it`s own storage because the on board storage will be so small. You can also map more memory in as pages but that requires more hardware. In the end you probably wont be able to use this for too much other than small stuff. You can build a small word processor or spreadsheet or whatever but it wont be as good as stuff on the modern PC. You`ll probably end up putting it aside at some point but if all you want is some learning experience then it may not be a total loss. After all, the...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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