Communication

About that exam

I am still waiting for some TinkerCad programs.

The textbook

It is now available on-line from UNC Asheville library!

Serial communication

In days past

When I was in graduate school serial lines connected terminals, such as the VT100, to computers. Graduate students and professors fought for access to these lines. These terminals performed astonishing GUIs using the VT52 escape sequences. And my friend Bill was talking about the UART (when he wasn’t talking about C4 square dance calls.

Working from home required the use modems. The Hayes Smartmodem allowed the transmission of data at an astonishing 300 baud. To allow control of these devices, Dennis Hayes invented what we now call the Hayes command set. This allowed computer geeks to initiate login sessions to remote computers. Soon almost all modems understood the Hayes command set.

Today

UART chips can be interfaced to processors with both I2C and SPI.

The Linux command stty sets baud rates and stop bits, and the Linux command screen emulates a VT100 terminal.

AT commands are still around.

And the best way of connecting an BNO055 to a Raspberry Pi is serial I/O.

Talking with an Arduino

Programming an Arduino with a Pi is just like using the workstation; though maybe a little slower. You can try this using a VNC connection. You may need to run raspi-config first.

I2C will work if the Raspberry Pi is the “master” and the Arduio is the “slave”.

The Raspberry Pi is 3.3V and the Arduino is 5.0V. Getting them to talk safely through a UART requires some help.

Even if you get them connected, you must disable getty on the port and (much harder) design a protocol for reading and writing messages through the serial port.

Perhaps for now, you would be satisfied with using Firmata. We did that in CSCI 182 last term.

udev