TTL COMPUTER BY ALESSIO LOMBARDO

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"Registers" Section

Architecture

The TTL Computer, in the Lite version and the Full version has 8 16-bit "general-purpose" registers:

"A1", "A2", "A3" and "A4" are used for the operand A

"B1", "B2", "B3" and "B4" are used for the operand B

Each register uses 2 SN74ALS573CN IC of Texas Instruments. Each Integrated Circuit has 8 Flip Flop "D". They are very similar to 74373. With them it is possible do four different operations: Write, Read, Sleep (NO Write and NO Read) and Transparent (Write and Read). The operations on the 8 registers (A and B) are controlled by a dedicated control unit that selects and decodes the operations of 2 registers at a time. With a LED Visualizer it is possible to identify the type of operation. The instructions arrive from an 8-bit Control Bus. The logical table of the Control Unit is as follows (with the colours of the LED):

Code Operation
A1 A2 A3 A4 B1 B2 B3 B4
0000 XXXX Trasparent Sleep Sleep Sleep Unknow Unknow Unknow Unknow
0001 XXXX Write Sleep Sleep Sleep Unknow Unknow Unknow Unknow
0010 XXXX Read Sleep Sleep Sleep Unknow Unknow Unknow Unknow
0011 XXXX Sleep Sleep Sleep Sleep Unknow Unknow Unknow Unknow
0100 XXXX Sleep Trasparent Sleep Sleep Unknow Unknow Unknow Unknow
0101 XXXX Sleep Write Sleep Sleep Unknow Unknow Unknow Unknow
0110 XXXX Sleep Read Sleep Sleep Unknow Unknow Unknow Unknow
0111 XXXX Sleep Sleep Sleep Sleep Unknow Unknow Unknow Unknow
1000 XXXX Sleep Sleep Trasparent Sleep Unknow Unknow Unknow Unknow
1001 XXXX Sleep Sleep Write Sleep Unknow Unknow Unknow Unknow
1010 XXXX Sleep Sleep Read Sleep Unknow Unknow Unknow Unknow
1011 XXXX Sleep Sleep Sleep Sleep Unknow Unknow Unknow Unknow
1100 XXXX Sleep Sleep Sleep Trasparent Unknow Unknow Unknow Unknow
1101 XXXX Sleep Sleep Sleep Write Unknow Unknow Unknow Unknow
1110 XXXX Sleep Sleep Sleep Read Unknow Unknow Unknow Unknow
1111 XXXX Sleep Sleep Sleep Sleep Unknow Unknow Unknow Unknow
XXXX 0000 Unknow Unknow Unknow Unknow Trasparent Sleep Sleep Sleep
XXXX 0001 Unknow Unknow Unknow Unknow Write Sleep Sleep Sleep
XXXX 0010 Unknow Unknow Unknow Unknow Read Sleep Sleep Sleep
XXXX 0011 Unknow Unknow Unknow Unknow Sleep Sleep Sleep Sleep
XXXX 0100 Unknow Unknow Unknow Unknow Sleep Trasparent Sleep Sleep
XXXX 0101 Unknow Unknow Unknow Unknow Sleep Write Sleep Sleep
XXXX 0110 Unknow Unknow Unknow Unknow Sleep Read Sleep Sleep
XXXX 0111 Unknow Unknow Unknow Unknow Sleep Sleep Sleep Sleep
XXXX 1000 Unknow Unknow Unknow Unknow Sleep Sleep Trasparent Sleep
XXXX 1001 Unknow Unknow Unknow Unknow Sleep Sleep Write Sleep
XXXX 1010 Unknow Unknow Unknow Unknow Sleep Sleep Read Sleep
XXXX 1011 Unknow Unknow Unknow Unknow Sleep Sleep Sleep Sleep
XXXX 1100 Unknow Unknow Unknow Unknow Sleep Sleep Sleep Trasparent
XXXX 1101 Unknow Unknow Unknow Unknow Sleep Sleep Sleep Write
XXXX 1110 Unknow Unknow Unknow Unknow Sleep Sleep Sleep Read
XXXX 1111 Unknow Unknow Unknow Unknow Sleep Sleep Sleep Sleep

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

As can be seen from the table, can be used at the same time only one Register A and one Register B. The other registers are in "sleeping mode", that is they are not doing anything.

Cards

The "Registers" section is composed of 4 cards grafted together with connectors. The 4 cards are:

Circuit Diagrams

Under design...

Photogallery

This is the photogallery of the "Registers" section. Click on photos to enlarge.

From top to bottom: "Registers - Control Unit" Card, "Registers - Registers A" Card, "Registers - Registers B" Card, "Registers - Data Bus" Card