Kits
›
Transistor Memory
RU
EN
ES
Contents
Before you start
A bit of history: how computers remembered
Lesson 1. Cell and row: a 4-bit word
1.1. The idea: memory is a lot of latches
1.2. The cell: a latch and a "tap"
1.3. The row: 4 cells with shared wires
1.4. Building
1.5. Check
Lesson 1 paste (Cmd+I)
Lesson 2. 16×4 memory: sixteen rows and picking one
2.1. The idea: pick one row out of sixteen
2.2. Why reading uses gates and not a shared wire
2.3. Building
2.4. Check
Lesson 2 paste (Cmd+I)
Lesson 3. 256×4 memory: the same circuit one level up
3.1. The idea: the address splits in half
3.2. The cost
3.3. Building
3.4. Check
Lesson 3 paste (Cmd+I)
Lesson 4. Your own memory in the processor — and the first error
4.1. What is in the machine now and how our memory differs
4.2. Memory at power-on — "whatever"
4.3. Building
4.4. Running it — and the error
4.5. Looking for the cause with the oscilloscope
Lesson 4 paste (Cmd+I)
Lesson 5. Two-phase clock: the write never meets a new address
5.1. The idea: put "new address" and "write" into different slices
5.2. Why it doesn't break now
5.3. Building
5.4. Check
Lesson 5 paste (Cmd+I)
Summary
All the parts
Instructions in pictures
Lesson 5 in pictures
← Back to the lesson: Lesson 5. Two-phase clock: the write never meets a new address
5
Two-phase clock
divide by 2 and a write window: the game works
kh
GW-03
Q
NOT
1×
AND
1×
DFF
1×
AND3
1×
∞
© 2026 Daniil Khanin · khanin.info · GW-03
51
GW-CPU
1
Delete
NOT
A
CPUCLK
Y
nCLK
AND
A
oST
B
nCLK
Y
weRAM
2
NOT
1×
AND
1×
DFF
1×
AND3
1×
13×
NOT
A
RST
Y
nRST
AND
A
nCLK2
B
nRST
Y
dCLK2
DFF
D
dCLK2
CLK
CPUCLK
Q
CLK2
nQ
nCLK2
AND3
A
oST
B
nCLK2
C
CPUCLK
Y
weRAM
© 2026 Daniil Khanin · khanin.info · GW-03
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GW-CPU …
3
ram ACC
Q0
acc0
CLK
CLK2
CPUCLK
on all 28 registers, pin CLK: label CPUCLK → CLK2
28×
ACC
FZ
FC
PC
PH
PT
P
HT
H
MT
M
STK
STATE
T0
T0HI
T1
T1HI
T2
T2HI
T3
T3HI
ARMS
BODY
MISS
OVER
FALL
COMET
LEVEL
⚠ don't rename this one: cut the wire and place a new label
CPUCLK
CPUCLK
CLK2
ram …
© 2026 Daniil Khanin · khanin.info · GW-03
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CANVAS
4
w
add · trig · FROZEN
CPUCLK
GW-CPU.CLK2
ir0-7
61
14
13
GW-CPU.oST
GW-CPU.weRAM
the window comes a slice after the address and closes early
Fast
Q
L
© 2026 Daniil Khanin · khanin.info · GW-03
54
← Back to the lesson
Lesson 5. Two-phase clock: the write never meets a new address