HOMEMADE TTL 4-bit Cpu
by G.G. (Italy)
APOLLO181 is a homemade didactic CPU made of bipolar logics and memories, characteristic of the TTL Bugbook® era in 1970s
Enjoy the project at
ygg-it.tripod.com/
Technology:
TTL Schottky (1974 Bugbook® era technology)
Data word size:
4-bit
Instruction word size:
8-bit
On-board RAM:
256 byte
On-board ROM:
64x16 bit
ALU type:
74181
Number of basic instructions:
16
Addressable memory locations:
256
Clock frequency:
2,5 MHz single phase
Clock cycles per instruction:
4
Interrupt levels (max):
256 without RTI
Number of internal registers:
16
Number of I/O ports (max):
16
Number of integrated circuit:
59
Board size:
300 x 300 mm (11,8 x 11,8 in.)
On board Power Supply (V/I)
5V/ 3500 mA (40VA transformer)
APOLLO181 has been conceived and assembled in Italy in 2012 by Gianluca G. (author of the homemade Z80/AM95 microcomputer) using early 1970s TTL technology. Designed and tested with the aid of a hardware simulator, APOLLO181 is running today at 2.5 MHz on a 12x12 inches single perfboard.
APOLLO181 is a multi-chip board and its peculiarity is that all the employed TTL components were described in the Bugbook® I & II (LOGIC & MEMORY EXPERIMENTS USING TTL INTEGRATED CIRCUITS, written by Dr. Peter R. Rony © 1974, 1st edition), as a Gianluca G.'s personal tribute to these books. By happy coincidence we are also approaching the 40 years Bugbook® publication anniversary.
