Communication Protocol
7 Communication Protocol
Table 4: Structure of the Protocol
MSB |
|
|
|
|
|
|
|
|
|
| LSB |
|
|
|
|
|
|
| INSTRUCTION |
|
|
| |
0 | TO PC |
| I5 | I4 |
| I3 |
| I2 | I1 |
| I0 |
7 | 6 |
| 5 | 4 |
| 3 |
| 2 | 1 | 0 | |
1st byte |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| DATA |
|
|
| |
1 | D6 |
| D5 | D4 |
| D3 |
| D2 | D1 |
| D0 |
7 | 6 |
| 5 | 4 |
| 3 |
| 2 | 1 | 0 | |
2nd byte |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| EXTENDED DATA |
|
|
| |||
1 | E6 |
| E5 | E4 |
| E3 |
| E2 | E1 |
| E0 |
7 | 6 |
| 5 | 4 |
| 3 |
| 2 | 1 | 0 | |
3rd byte |
|
|
|
|
|
|
|
|
|
|
|
|
| MSB’s |
|
|
|
|
|
|
| ADDR | |
1 | E7 |
| D7 | 0 |
| 0 |
| 1 | 1 |
| 0 |
7 | 6 |
| 5 | 4 |
| 3 |
| 2 | 1 |
| 0 |
4th byte1 |
|
|
|
|
|
|
|
|
|
|
|
Note that the MSB’s of the DATA (D7) and the EXTENDED DATA (E7) are in the fourth byte.
Terminology:
•TO PC is the “DESTINATION BIT”
•I4..I0 is the “INSTRUCTION”
•D7..D0 is the “DATA”
•E7..E0 is the “EXTENDED DATA”
•A0 is the “LSB of the MACHINE ADDRESS”
The destination bit, TO PC, is 0 when sending from the PC to the machine, or 1 when sending from the machine to the PC.
Table 5: Instruction Set for the 7508
# | INSTRUCTION | I5 | I4 | I3 | I2 | I1 | I0 |
0 | Reset | 0 | 0 | 0 | 0 | 0 | 0 |
1 | Read video standard | 0 | 0 | 0 | 0 | 0 | 1 |
3 | Read | 0 | 0 | 0 | 0 | 1 | 1 |
10 | Write EEPROM data – low address | 0 | 0 | 1 | 0 | 1 | 0 |
11 | Read EEPROM data – low address | 0 | 0 | 1 | 0 | 1 | 1 |
12 | Write I²C | 0 | 0 | 1 | 1 | 0 | 0 |
13 | Read I²C | 0 | 0 | 1 | 1 | 0 | 1 |
16 | Error | 0 | 1 | 0 | 0 | 0 | 0 |
57 | Enable | 1 | 1 | 1 | 0 | 0 | 1 |
61 | Identify machine | 1 | 1 | 1 | 1 | 0 | 1 |
1 Note that the MSB’s of the DATA (D7) and the EXTENDED DATA (E7) are in the fourth byte
10 | KRAMER: SIMPLE CREATIVE TECHNOLOGY |