diff --git a/README.md b/README.md
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--- a/README.md
+++ b/README.md
@@ -10,4 +10,5 @@
 # Arduino Interface
 
 ## Bus Ideas
-- [74HC245](./datasheets/74HC_HCT245.pdf), also possible for GPU buffer switching
+- [74HC245](./datasheets/74HC_HCT245.pdf), bidirectional 3-state bus transciever, also possible for GPU buffer switching
+- [74HC138](./datasheets/74HC_HCT138.pdf), 3->8 address decoder 
diff --git a/datasheets/74HC_HCT138.pdf b/datasheets/74HC_HCT138.pdf
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diff --git a/datasheets/74HC_HCT377.pdf b/datasheets/74HC_HCT377.pdf
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diff --git a/datasheets/ENC28J60.pdf b/datasheets/ENC28J60.pdf
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diff --git a/datasheets/LY62256PL-55LL.pdf b/datasheets/LY62256PL-55LL.pdf
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diff --git a/design/~6502.kicad_sch.lck b/design/~6502.kicad_sch.lck
new file mode 100644
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--- /dev/null
+++ b/design/~6502.kicad_sch.lck
@@ -0,0 +1 @@
+{"hostname":"MAXIMESPC","username":"Maxime Vorwerk"}
\ No newline at end of file
diff --git a/notes/cpu.md b/notes/cpu.md
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--- /dev/null
+++ b/notes/cpu.md
@@ -0,0 +1,10 @@
+# CPU board
+
+## Components
+- CPU: [W65C02](../datasheets/w65c02s.pdf)
+- RAM: [LY62256PL-5LL](../datasheets/LY62256PL-55LL.pdf)
+- ROM: [AT28C64B](../datasheets/AT28C64B.pdf)
+- Register: [74HC377](../datasheets/74HC_HCT377.pdf)
+
+## Timings
+- PHI2 target: 10MHz -> 100ns
diff --git a/notes/memory-layout.md b/notes/memory-layout.md
index 9b6c3cf..3ba0567 100644
--- a/notes/memory-layout.md
+++ b/notes/memory-layout.md
@@ -2,6 +2,7 @@
 - bank switching using 8-Bit register
 - top 32K remain untouched
 
+# [CPU](./cpu.md)
 | start  | end    | use                     |
 | :----- | :----- | :---------------------- |
 | 0x0000 | 0x5FFE | RAM                     |
@@ -9,7 +10,7 @@
 | 0x6000 | 0xDFFF | --- to be mapped ---    |
 | 0xE000 | 0xFFFF | ROM                     |
 
-# Default (0X00)
+# I/O (0x00)
 | start  | end    | use |
 | :----- | :----- | :-- |
 | 0x6000 | 0xDFFF | I/O |