More TECS

Finally finished the exercises for Chapter 2 in TECS. This chapter builds on the basic logic gates introduced in Chapter 1 to build more complex circuits, including a 16 bit adder and an Arithmetic Logic Unit, which will be the basis for the computer developed in subsequent chapters. Designing the ALU is the first exercise which gave me some trouble. There are some things that you can't easily do with the hardware description language that would help. For example, directly connect two pins, such as an internal and output pin. Instead, all of the connections have to happen in the input or output specifications for parts within the chip. This is a problem when you want an output pin of a part to connect to both the output of the chip and another internal part.

No big deal, since there are straightforward work-arounds. After putting in the effort to get it right, it was very satisfying to see my design pass the automated tests.

Next up is sequential logic, with fun stuff like flip-flops, registers and RAM banks.