** my board

In my board design, on the ATTiny44, pin 5 is connected to the
LED. This corresponds to register PB2.

Similarly, pin 11 is connected to the switch. Register PA2.

Apparently the button has convention 0 = pressed, 1 = unpressed.

** make
To be run only once, when you first build the board (to set the clock rate)
#+BEGIN_SRC 
make avrisp2-fuses
#+END_SRC

To be run each time you want to download a new program:
#+BEGIN_SRC 
make avrisp2
#+END_SRC

This Makefile compiles a c file (the PROJECT variable in the makefile)
into attiny code and downloads it onto the machine. The target changes
depending on what the programmer is. avrisp2 is the small blue box one.

misc command:
#+BEGIN_SRC 
avrdude -p t44 -c avrisp2 -v
#+END_SRC

** picocom


Install picocom.
#+BEGIN_SRC 
sudo picocom -b 115200 /dev/ttyUSB0
#+END_SRC

-b is baud rate which we learned from reading hello world.



C-a C-x to exit picocom.


** Reading and writing
Registers are named after pins (A0, A1, B0, B1, etc.)

two registers important for writing

to write to port a, two registers: DDRA,

DDRA tells each pin whether each pin is an input or output

PORTA defines the output states of the output pin. 

on inputs PORTA tells input pins whether to float (0) or not (1).
Connecting to a capacitative element e.g. touch-capacitance.



PINA read inputs