Kramer Electronics 7408 - Manual (Page 11)

Communication Protocol (Ver 0.1)
9
7 Communication Protocol (Ver 0.1)
RS-232 communication between the 7408 and the PC is done using the following protocol. The protocol uses four bytes of
information, and data is at 9600 baud, no parity, 8 data bits and 1 stop bit. The controller and machine should be connected
via a null-modem connection, that is, if using a DB-9 port, connect as follows:
Connect pin 5 of the PC to pin 5 of the machine
Cross pins 2 and 3, i.e., connect pin 2 of the PC to pin 3 of the machine, and connect pin 3 of the PC to pin 2 of the machine
On the PC side, short pins 4 and 6
On the PC side, short pins 1, 7 and 8
Table 5: 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 1 1 1 0
7 6 5 4 3 2 1 0
4th byte 1
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”
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 6: Instruction Set for the 7408
INSTRUCTION I7 I6 I5 I4 I3 I2 I1 I0
Dec Hex
0 0 Reset 0 0 0 0 0 0 0 0
3 3 Store machine settings 0 0 0 0 0 0 1 1
4 4 Recall machine settings 0 0 0 0 0 1 0 0
5 5 Set Video Parameter 0 0 0 0 0 1 0 1
6 6 Request Video Parameter 0 0 0 0 0 1 1 0
7 7 Read video encoder data 0 0 0 0 0 1 1 1
8 8 Write video encoder data 0 0 0 0 1 0 0 0
10 A Write EEPROM data 0 0 0 0 1 0 1 0
11 B Read EEPROM data 0 0 0 0 1 0 1 1
12 C Write I²C 0 0 0 0 1 1 0 0
13 D Read I²C 0 0 0 0 1 1 0 1
14 E Read video standard 0 0 0 0 1 1 1 0
15 F Is setup defined? 0 0 0 0 1 1 1 1
16 10 Error 0 0 0 1 0 0 0 0
30 1E Lock Front Panel 0 0 0 1 1 1 1 0
31 1F Request Bar 0 0 0 1 1 1 1 1
57 39 Enable “Power-down save” 0 0 1 1 1 0 0 1
61 3D Identify machine 0 0 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