RS232 to SPI Interface This project is a Microchip PIC microcontroller with an RS232 serial interface on one side and an SPI interface on the other. The SPI interface uses the SSP port on a 16F819 device. By sending commands on the RS232 interface it is possible to send any sequence of bytes on the SPI interface from the PIC. These can enable or disable the chip select and read, write or exchange a sequence of bytes. I2C or SPI Serial Communication ? Before adding serial communication to your design, let’s say adding a serial eeprom, you should have an understanding of the different types of serial communication that you can use. There are two main protocols to consider, SPI protocol and I2C protocol. Both systems have their unique advantages and disadvantages which make them more or less suitable for a given application. Digital caliper to computer (RS-232) interface This is an electronic digital caliper to computer (RS-232) interface. This will work with the inexpensive calipers, micrometers and height gauges that are typically made in China. The connector on the measuring instrument will have 4 pins, and the owner’s manual will typically describe the output as 24 bit 90 kHz synchronous. This does not work the name brand instruments - Fowler, Mitutoyo, Brown & Sharpe, etc. The caliper sends a burst of data approximately three times each second. Each burst contains 48 bits of data as shown in timing.pdf. The first 24 bits are the position relative to the zero point set on the caliper. The second 24 bits are the position relative to an arbitrary zero that does not change. This is sort of an absolute position, but the zero point changes each time the caliper loses power. Each 24 bit value is in ones compliment form (1 sign bit, 23 data bits). This allows for a 0 and a -0. The unit of measure is 1/20480th of an inch. [image source: www.hobbytoolsupply.com] OBD2 ELM327 compatible AllPro adapter with USB On PC desktops the RS-232 serial ports are about to disappear from most computers (especially from laptops), replaced by the USB connection. This project was begun as a response to build simple ELM327 compatible USB adapter for On Board Diagnostic (OBD2) monitoring. OBD2 ELM327 compatible AllPro adapter with USB Posted by admin on April 20th, 2 This project is a Microchip PIC microcontroller with an RS232 serial interface on one side and an PS/2 (keyboard or mouse) interface on the other. The PS/2 interface uses bit-banging on a 12F683 device. The PS/2 interface operates as a host and initialises the keyboard or mouse before going into a never-ending loop of reading the data and sending it to the RS232 interface. RS232 to I2C Interface This project is a Microchip PIC microcontroller with an RS232 serial interface on one side and an I2C interface on the other. The I2C interface uses bit-banging on an 12F675 device. By sending commands on the RS232 interface it is possible to build up an I2C command in RAM in the PIC. After the final byte is sent on the RS232 interface the PIC will run through the stored sequence and send it out on the I2C interface, storing any data that has been read back. When the I2C command has finished the whole thing is copied back out of the RS232 interface. Reading the data output from cheap digital verniers and scales The circuit make good use of the on-chip comparator in a single 12F675 PIC to detect the low level data and clock signals from the scales. The firmware reads both 24 bit binary and 7 digit BCD output scales types, can switch the scale to fast or slow reading, zero the scale display and outputs the data in an easily readable format at 115,200 Baud. Mechanical hit-counter using serial port is is a physical hit counter.It is used to count page-hits on the website instead of using software only.The counter will connected to rs232 port through a few of electronic components that preform as a counter driver and power supply circuit.The counter that I used is a machanical counter or electromagnetic counter model SC-212 which I get from an old coin-op game machine as show in the photo.As the counter’s nameplate specified, this counter requires 12VDC power supply , this means that it requires a 12V pulse to increase the counter by 1.Also,the in the nameplate show the maximum speed is 15 CPS but I not use beyond this speed in my project. [via] USBGame12 - an Interface for Simple Joysticks This interface offers 12 digital inputs presented to the operating system as USB joystick with 4 directional buttons and 8 general purpose buttons. It can be used to connect historic joysticks or for general purpose digital inputs.This project uses an ATmega8 microcontroller from Atmel. and used the software-only usb driver from Objective Development. General purpose infrared remote control receiver with RS232 output I have done a simple infrared remote control receiver with RS232 ascii output. It can be used for developing remote controls on a PC using the serial port. In practice, the infrared bursts are converted in ascii characters and sent to the RS232 port. The downloadable ZIP file contains the schematic diagram , the printed circuit board, the components disposition and the object file to write into the ATMEL ATtiny2313 microcontroller. |
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