Kramer Electronics 7508 User Manual download pdf (Page 12)

KRAMER: SIMPLE CREATIVE TECHNOLOGY

Communication Protocol

7 Communication Protocol

RS-232 communication with the 7508 complies with the following protocol.

The protocol uses 4 bytes of information, and data is at 9600 baud, with no

parity, 8 data bits and 1 stop bit.

Table 4: Structure of the Protocol

MSB

LSB

INSTRUCTION

TO PC

7 6 5 4 3 2 1 0

1st byte

DATA

2nd byte

EXTENDED DATA

3rd byte

MSB’s

ADDR

4th byte

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

Reset

Read video standard

Read back-panel DIP-switch 1 (video format CV/YC)

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

Error

Enable “Power-down save”

Identify machine

1 Note that the MSB’s of the DATA (D7) and the EXTENDED DATA (E7) are in the fourth byte

1 2 ... 7 8 9 10 11 12 13 14 15

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Kramer Electronics 7508 User Manual Page 12