Contents

1. Before you start
2. A bit of history: how computers remembered
3. Lesson 1. Cell and row: a 4-bit word
   1. 1.1. The idea: memory is a lot of latches
   2. 1.2. The cell: a latch and a "tap"
   3. 1.3. The row: 4 cells with shared wires
   4. 1.4. Building
   5. 1.5. Check
   6. Lesson 1 paste (Cmd+I)
4. Lesson 2. 16×4 memory: sixteen rows and picking one
   1. 2.1. The idea: pick one row out of sixteen
   2. 2.2. Why reading uses gates and not a shared wire
   3. 2.3. Building
   4. 2.4. Check
   5. Lesson 2 paste (Cmd+I)
5. Lesson 3. 256×4 memory: the same circuit one level up
   1. 3.1. The idea: the address splits in half
   2. 3.2. The cost
   3. 3.3. Building
   4. 3.4. Check
   5. Lesson 3 paste (Cmd+I)
6. Lesson 4. Your own memory in the processor — and the first error
   1. 4.1. What is in the machine now and how our memory differs
   2. 4.2. Memory at power-on — "whatever"
   3. 4.3. Building
   4. 4.4. Running it — and the error
   5. 4.5. Looking for the cause with the oscilloscope
   6. Lesson 4 paste (Cmd+I)
7. Lesson 5. Two-phase clock: the write never meets a new address
   1. 5.1. The idea: put "new address" and "write" into different slices
   2. 5.2. Why it doesn't break now
   3. 5.3. Building
   4. 5.4. Check
   5. Lesson 5 paste (Cmd+I)
8. Summary
9. All the parts
10. Instructions in pictures