The basic requirement was for some sort of output display and some sort of alpha-numeric input. So the simplest solution I could think of was a UART, attached to something with a screen and keyboard running a serial terminal. I looked at using the PIC already in the system as a UART as well, but decided that it would be better used as a fast DMA c
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ontroller with all its pins allocated to that. I had a 6402 UART chip of a similar vintage to the Z80 CPU lying around so that became the core of the UART peripheral. There are three peripheral chips in the UART system, a 74HC4060 clock/divider chip, a MAX232 RS232 level shifter and a 74LS541, an 8 bit tri-state buffer. The clock/divider chip provides an independent clock source for the UART from the CPU clock. The UART clock has to match the baud-rate so needs to be a fairly weird frequency. The 6402 needs 16 times the baud-rate as an input clock, so I`ve used a 4. 9152MHz crystal. Taking the Q6 (divide by 64) output this gives 4800 baud, the Q5 (divide by 32) output gives 9600 baud and so on. I`ve used a jumper block to allow a baud rate from the range 4800, 9600, 19200 or 38400. The MAX232 chip provides the big voltages needed for "true" RS232 signalling. If you`ve made anything with a serial interface before you`ll probably be familiar with this or a similar chip (e. g. the MAX202). There`s a bunch of electrolytic caps attached to this to make the suitable voltage step-ups. If you`re using a TTL level USB interface e. g. an FT232 based device, you need to skip the level translator, but I`m planning on plugging this into a real serial port on some old hardware I have. The final peripheral chip is the tri-state buffer. This buffers the status flags from the UART and allows them to drive the data bus when a "status...
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....
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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....
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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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