This chapter contains the description of a simple development board for the study of the 8051 family of microcontrollers Unlike the development boards dedicated to the HC11 and AVR families, presented in the previous chapters, this project allows the user to load and execute programs in an external RAM area, addressed to be visible both in the p
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rogram memory and data memory address space. The schematic of the board is presented in Fig. 11. 1, 11. 2, and 11. 3. Figure 11. 1 shows the microcontroller IC10, the bus demultiplexer IC7, the RS232 interface IC12, the RESET and clock circuits, and the ISP connector SV1. Note the presence of the two NAND gates IC6C and IC6D, which implement the logic function AND between the signals RD (Read) and PSEN (Program Store Enable), both active LOW, and generate the signal RDPSEN. RDPSEN is active LOW when either RD or PSEN is LOW. Connecting this signal to the RD input of an external RAM circuit allows the use of this RAM to store program as well as data. The microcontroller can be any of 8032, 8051, 8052, AT89C51, AT89C52, etc. in a DIP40 package. The input EA (External Access) of the MCU is connected to the jumper JP1 to allow the use of the internal ROM, if this is available. Connect the jumper so that EA = 1 to use the internal ROM. When the external ROM is.
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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....
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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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