It's actually using a Harvard architecture. From Part 4: > Harvard architecture, meaning a division between program memory (ROM) and data memory (RAM). Althoug

It's actually using a Harvard architecture. From Part 4: > Harvard architecture, meaning a division between program memory (ROM) and data memory (RAM). Although this does reduce the flexibility of the processor, this helps with size optimization: the length of the program is much larger than the amount of RAM we'll need, so we can split the program off into ROM and then focus on compressing the ROM, which is much easier when it is read-only.