38
MAS-6100 / MAS-6100A
experiment and satisfy themselves that this is possible.
Checksums
The protocol requires checksums on all commands. The checksum is the sum of all previous bytes (excluding
the SOP ‘F’ character). The checksum is calculated on the hex value of the two ASCII bytes. For example, the
command “F0400410082000001C8” has the checksum of C8 (04+00+41+00+82+00+00+01=C8). A short-
cut for debugging allows the checksum to be replaced by 2 question marks, so in the previous example you
could send F0400410082000001?? Instead. This is purely for test and debugging - you should normally use a
checksum to ensure data validity.
Carriage Returns
Each packet that is sent to or received from the MAS-6100 is terminated with a carriage return. Carriage return
has a value of 13 decimal, but is sent as a hex byte 0x0D. It will be represented in this document as <CR>.
PACKET FORMAT
Read Packets
Below is a representation of data bytes in a single packet for a ‘Read’ to the unit to get a value:
SOP
CMD
CHA
WINDOW/FUNCTION
OUTPUT
FUNCTION
CS
EOP
The table below details the function of each part of the packet:
Packet part
Function
SOP
(Start of
packet)
This is always the ASCII letter ‘F’ to indicate the packet start.
CMD
(Command)
ASCII-hex byte to indicate the type of command being sent.
Each bit in the byte has a different function.
Bit 7 = Write (0) or Read (1) request. Messages from the unit are always Writes.
Bit 6 = ACK bit. Should be set to 0 for messages to the unit.
ACK=1 returned means message was okay.
ACK=0 returned means an error was present in the message.
Bit 5:3 = 0 Reserved for future use.
Bit 2 = 1 This bit *must* be set.
Bit 1:0 = 0 Reserved for future use.
SOURCE
This byte has multiple uses, and defaults to 0 unless used for:
SOURCE
Byte to indicate the source channel to be altered (if appropriate).
0x10 = RGB1
0x11 = RGB2
0x30 = VIDEO1
0x31 = VIDEO2
0x40 = S-VID1
0x41 = S-VID2
WINDOW
Bit 7 = 0 (Reserved).
Bit 6..0 = Window ‘A’ is sent as ‘41’ since 0x41 is ASCII for ‘A’.
OUTPUT
&
FUNCTION
HIGH
Bit 7..4 = 0
Bit 3..2 = Reserved (set to 0).
Bit 1..0 = Bits 9 & 8 of the function code. (Remainder of bits [7..0] are in FUNC LOW.)
Example: If the function code is 0x234, then these bits are 0x02.
FUNCTION
LOW
ASCII-hex byte to indicate the lowest 8 bits of the actual function to set or receive..
A later table details all the functions available.
CS
ASCII-hex, see above.
EOP
<CR>
Содержание MAS-6100
Страница 36: ...36 MAS 6100 MAS 6100A...
Страница 50: ...50 MAS 6100 MAS 6100A...
Страница 53: ...MAS 6200...
Страница 54: ...MAS 6200...