Overview Of Commands; Protocol - Roland M-400 Reference Manual

Overview of commands

The M-400 and the control computer communicate via commands.
There are several types of commands, and you can control the M-400 by using the command that's
appropriate for your purpose.
Overview of commands
Single-byte alphanumeric characters are used for commands.
In general, the command syntax is an ASCII string consisting of "stx" and "three uppercase letters" followed
by a ";" (semicolon).
The three letters indicate the type of command. However, there are other types depending on the command.
(Refer to "Command syntax" (p. 9))
* "stx": This is the name of the signal in ASCII code (code number 02H in hexadecimal); it is a control code that indicates
the beginning of a command.
* ";": This code lets the M-400 detect the end of the command.
<Ex.> To transmit the ** command, transmit the ASCII string "stx**;"

Protocol

Depending on the command, there are two types of communication protocols between the control computer
and the M-400.
1.
When specifying an operation or setting for the M-400
This type corresponds to the "Control commands" (p. 11).
These commands use the procedure shown in the following diagram.
fig.PrtConcept1.eps
COMPUTER
a. Transmit the command from the computer to the M-400.
b. The M-400 will output " ack " if the command was received correctly, or an ERR command in case of
invalid reception.
* "ack": This is the ASCII code name of the control code (06H in hexadecimal) acknowledging successful reception.
* Invalid reception corresponds to cases in which the syntax of the received command was incorrect.
* stxERR is the command used to transmit or receive an error indication.
8
a. stx + command
b. ack or stxERR command
M-400