Crossroads - 26/04/19

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Crossroads was an improved version of Trinity. It had an improved instruction set, more RAM, and was built as a standalone module. This version took about 18 hours in total to make, but that was spread across a couple of months.

• 8/4 bit bus width
• 7 instructions: ADD, AND, OR, NOT, LDA, JMP, STA
• 15 bytes of memory

The full computer

The ALU

The ALU in crossroads has more functions that in Trinity, with not, or, and, and add, in that order. Each yellow line is the enable line for that alu function.

The memory

This memory still uses D flip-flops, but they use a different design, this time using locking repeaters, and they are orientated vertically, to save space. However, they are still quite large, making large amounts of memory hard to load all at once.

The Program Counter

This is pretty much the exact same as the PC from Trinity. The increment circuit is more visible here.