– A PC, Raspberry Pi or another Linux or Windows PC. And act as the power supply the little computer.īased on special UAR/T IC’s, very small footprint, and dirt cheap. Throw out the overhead of the + and -15v, limit or leave out the handshake signals, (mis)use the DTR signal to reset the Arduino, use it to download firmware or collect data from sensors on the small computers and process it on bigger machines. These little devices came into use to communicate with small computers like SBC’s, Arduino and ESP’s and PC’s. RS-232: Serial Ports USB Serial TTL devices This picture shows where RS232 came into being about 50 years ago,įundamentals of RS–232 Serial Communications You will learn and know what I am talking about: DCE, DTE, DSR, DTR, TxD, RxD, CTS, RTS, DTR, RI, CarrierDetect, UAR/T’s, TTL voltage levels being reverse to RS232 voltage levels, a ‘0’ being negative RS232 voltage up to 15V, a ‘1’ being as low as -15V. If you are new to the serial world and want to use these devices and understand how, study the next chapter. And so common nowadays in Arduino and ESP8268, ESP32 and even Raspberry Pi world.

Terminology, asynchronous serial format, voltage levels, start bits, stop bits, 7 or 8 data bits, hardware and software handshake, and the way it is abused in many of these devices. These are all descendants of the EIA RS232 standard in some way. Most not documented or unsure if the voltage levels are 3.3V or 5V. So I have a collection of those USB to serial adapters, some with cables and DB-9 connectors, some with cable and Dupont connectors, and some USB TTL type connectors on a PCB with male or female Dupont pin connectors for USB-A, mini or micro USB.

Mini usb pinout download