KRAMER: SIMPLE CREATIVE TECHNOLOGY
Communication Protocol
38
11 Communication
Protocol
This protocol, which enables RS-232 communication between the
VP-26
and the PC, uses 4 bytes of information, and data is at 9600 baud, no parity,
8 data bits and 1 stop bit.
Table 17: Protocol Definitions
MSB LSB
DESTINATION
INSTRUCTION
0 D
N5 N4 N3 N2 N1 N0
7
6
5 4 3 2 1 0
1st byte
INPUT
1
0
0 0 0 I2 I1 I0
7
6
5 4 3 2 1 0
2nd byte
OUTPUT
1
0
0 0 0 0 O1
O0
7
6
5 4 3 2 1 0
3rd byte
MACHINE NUMBER
1 0
0 0 M3 M2 M1 M0
7
6
5 4 3 2 1 0
4th byte
1st BYTE:
Bit 7 – Defined as 0.
D – “DESTINATION BIT”.
This bit is always low, when sending from the PC to the switchers, and high for information sent to the PC.
N5…N0 – “INSTRUCTION”.
These 6 bits define the function that is to be performed by the switcher(s). Similarly, if a function is performed via the
machine’s keyboard, then these bits are set with the INSTRUCTION NO, which was performed. The instruction codes are
defined according to the table below (INSTRUCTION NO. is the value to be set for N5…N0).
2nd BYTE:
Bit 7 – Defined as 1.
Bits 3 – 6 - Defined as 0.
I2… I0 – “INPUT”.
For disconnect, set as 0. For other operations, these bits are defined according to
Table 18
.
3rd BYTE:
Bit 7 – defined as 1.
Bits 2-6 defined as 0.
O1, O0 – “OUTPUT”
For operations, these bits are defined according to
Table 18
.
4th BYTE:
Bit 7 – Defined as 1.
Bits 3-6 Defined as 0.
M3… M0 – “MACHINE NUMBER”.
MACHINE NUMBER = (DIPSWITCH CODE) + 1.
