TTL COMPUTER BY ALESSIO LOMBARDO
[HOME] [WORKLOG] [HARDWARE] [CONTACT-ME] [ ]
"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:
Registers - Control Unit: Selection of the registers and decoding instructions. It has the Visualizer with 8 bi-color LED
Registers - Registers A: It contains 8 74573 IC, that is the 4 "A" registers (A1, A2, A3, A4)
Registers - Registers B: It contains 8 74573 IC, that is the 4 "B" registers (B1, B2, B3, B4)
Registers - Data Bus: It distributes the Data Bus and the power supply to the cards "Registers A" and "Registers B"
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