DUO BINARY

Make a computer with a single LED and single button interface (single wire I/O). It should have a lot of storage and memory. The computer should interpret a simple bytecode.

Parts to use:
Microcontroller: ATTINY84-20PU
(x2) 3 pin male header: 69190-403
2 MB flash: SST25VF016B-50-4C-S2AF
128 KB SRAM: 23LC1024-I/P
14 pin IC socket: 4814-3000-CP
8 pin IC socket: 4808-3000-CP
(x2) 4 pin female header: 929974-01-04-RK
(x2) 4 pin male header: 68000-104HLF
SOIC to DIP board: 485-1212
(x3) 0.1 uF capacitor: K104K15X7RF5TL2
Button: B3F-1000
LED: WP7113GD
300 ohm resistor: 291-330-RC
(x5) 10K ohm resistor: 291-10K-RC
(x1 for microcontroller reset, x1 for MISO, x1 for flash CE, x1 for SRAM CE, x1 for button)
Larger capacitor: UVR1H100MDD1TA
Switch: MHSS1104
Battery holder: 534-2462

"User interface":
The user and computer take turns transmitting 6-bit character encoded strings to each other. Strings are terminated by the null character. Characters are transmitted from most significant to least significant bit. After each character the listener will transmit an acknowledge bit. If the acknowledge bit is 1, the transmitter should send the same byte again. A 0 is represented by a short pulse. A 1 is represented by a long pulse.

File system:
Each file will be stored in a single continuous segment. Each file will be associated with a name. Some programs will have associated export files. These export files contain addresses of public functions and argument variables.

File entry format:
(1 byte entry type) (4 byte file data size) (4 byte file allocation size) (4 byte file address) (51 byte null terminated file name)
Total size: 64 bytes
Entry types:
0 = End of entry list
1 = No entry
2 = Yes entry

Storage layout:
(4 KB jump table) (8 KB file entry table) (52 KB boot code) (file space)

Monitor program commands:
S-110010 (3 byte address) = Seek
T-110011 = Tell
R-110001 (1 byte amount) = Read
W-110110 (byte) (byte) (byte)... = Write
E-100100 (3 byte amount) = Erase
Q-110000 = Quit

Bytes are encoded as two letters between A-100000 and P-101111 inclusive.

Space is 000010.

Memory allocation format:
(4 byte next allocation) (4 byte previous allocation) (4 byte size) (data)

File navigator commands:
CN (name) = Create new file
C = Count
OI (index) = Open by index
ON (name) = Open by name
N = Get name
S = Get size
A = Get address
SN (name) = Set name
SS (size) = Set size
E = Execute
D = Delete

Typological Editor commands:
N = New buffer
R (name) = Read file
W (name) = Write file
L = Print length
S (index) = Seek
T = Tell
P (amount) = Print text
I (text) = Insert
D (amount) = Delete