Biamp VRAM RS-232 User Manual

Serial Control

of the

Advantage VRAM

_______________________________________________________________________________________

Biamp Systems, 10074 S.W. Arctic Drive, Beaverton, Oregon 97005 U.S.A. [phone]

an affiliate of Rauland-Borg Corp.

Introduction

This document contains information for the serial control of the Advantage VRAM
(Variable Resource Auto Mixer) and the Advantage VRAMeq, (Variable Resource Auto
Mixer with equalizer). Specifically, this document tries to inform those looking to write
their own software controls for the Advantage VRAM. It is assumed that the reader has
some familiarity with standard programming practices, binary and hexadecimal numbers,
the ASCII character set, asynchronous serial data connections, and RS-232 interfaces.

Decimal, Binary, and "Pseudo-hex" Numbers

This document uses three different numerical notations. The first, the most common, is
the decimal notation. Whenever it is used, a “d” will appear after the number..

8 Bit binary numbers are the second format used in this paper. These numbers will be
followed by “b” after their usage. If a specific bit is being referred to, the numbers will
be preceded by the word “bit.”

To transmit an 8 bit binary number to the Advantage VRAM, hexadecimal notation is
used. Hexadecimal numbers are arrived at by splitting the number into two halves. One
half consists of the first four binary digits (most significant nibble) while the other
consists of the last four binary digits (least significant nibble). 2 nibbles form a byte,
which takes on a decimal value of 0 to 255. Each half is then assigned a hexadecimal
value. Since the binary values range from 0 to 15, usually values from 10 to 15 are given
the alphabetic letters from A to F.

However, the Advantage VRAM does not utilize standard hex format. Instead, the
Advantage VRAM uses what is known as "pseudo-hex." Simply put, instead of using the
letters A, B, C, D, E and F the Advantage VRAM uses : ; < = > and ?, respectively. All it
takes to arrive at the new notation for hex values 10 to 15d is to add 30 to the old ASCII
values. In this paper, [pseudo-hex] will appear after the use of a pseudo-hex character.
The changes are traditional hex are summed up below:

Nibble Conversion

Decima

l

0 0 0 0000
1 1 1 0001
2 2 2 0010
3 3 3 0011
4 4 4 0100
5 5 5 0101
6 6 6 0110
7 7 7 0111
8 8 8 1000

9 9 9 1001
10 A : 1010
11 B ; 1011
12 C < 1100
13 D = 1101
14 E > 1110
15 F ? 1111

Hex Pseudo-hex Binary

Serial Interface - Data Communications Parameters

The Advantage VRAM communicates through its serial port at four different baud rates:
2400, 9600, 19200, and 38400. The factory default setting is 9600 baud. Changing this
rate is accomplished in the advanced mode (see page 18, not a recommended procedure)
or through BiampWin. The Advantage VRAM communicates with 8 data bits, no parity,
and 1 stop bit. The Advantage VRAM utilizes a subset of the standard 7-bit ASCII
character set.

Control

The Advantage VRAM has an RS-232-compatible serial port which allows it to be
controlled by a computer or by a third party system controller (such as those provided by
AMX or Crestron). The Advantage VRAM offers the following two methods of serial
control:

• Control Button Emulation. This method of control emulates Biamp's standard infrared
remote control transmitter or wall-mount remote control panel. Using this method, single
ASCII characters sent to the device’s serial port cause the device to behave as if a biamp
remote controller were attached. While Control Button Emulation is simple to perform, it
only provides basic and "one-way" control of the Advantage VRAM - it allows the user
to send simple commands to the Advantage VRAM, but it does not provide any
mechanism for requesting status information from the Advantage VRAM.

• Advanced Control. Advanced control provides a command set which allow "two-way"
control of the Advantage VRAM. Using Advanced Control commands, a system may
request status information from the device as well as send commands to the device.
Communication occurs with the Advantage VRAM using the Advantage VRAM’s serial
port.

Control Button Emulation

Control Button Emulation is the simplest form of serial control of the Advantage VRAM.
This method of operation allows the user to emulate the operation of a standard Biamp
remote control transmitter.

For each button on a standard Biamp remote control, there is a corresponding ASCII
character. In order to emulate a remote control button, the transmitting system simply
transmits the corresponding ASCII character to the Advantage VRAM’s serial port.
Each character received by the Advantage VRAM will be echoed back out the serial port.

The standard Biamp remote control devices never exceed a transmission rate of 9
characters per second. If the controlling system wishes to perform Control Button
Emulation at a rate of greater than 20 characters per second (50 msec per character), flow

Serial Control of the Advantage VRAM

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control should be implemented by waiting for the echo of each character before
transmitting the next character. At slower speeds, flow control should not be necessary.

The following table summarizes the ASCII character codes for Control Button Emulation
corresponding to each of the 40 remote control buttons supported by the Advantage
VRAM. These button codes are also summarized on the ASCII code chart provided at
the end of this manual. The remote control buttons on the standard Biamp transmitter are
numbered from left to right going from bottom to top with the lower left-hand button
being button number 1.

Using BiampWin, it is possible to program the VRAM to respond to these commands.

button 1 'B' (0x42) button 21 'V' (0x56)
button 2 'C' (0x43) button 22 'W' (0x57)
button 3 'D' (0x44) button 23 'X' (0x58)
button 4 'E' (0x45) button 24 'Y' (0x59)
button 5 'F' (0x46) button 25 'Z' (0x5A)
button 6 'G' (0x47) button 26 '[' (0x5B)
button 7 'H' (0x48) button 27 '\' (0x5C)
button 8 'I' (0x49) button 28 ']' (0x5D)
button 9 'J' (0x4A) button 29 '^' (0x5E)
button 10 'K' (0x4B) button 30 '_' (0x5F)
button 11 'L' (0x4C) button 31 '`' (0x60)
button 12 'M' (0x4D) button 32 'b' (0x62)
button 13 'N' (0x4E) button 33 'c' (0x63)
button 14 'O' (0x4F) button 34 'd' (0x64)
button 15 'P' (0x50) button 35 'e' (0x65)
button 16 'Q' (0x51) button 36 'f' (0x66)
button 17 'R' (0x52) button 37 'g' (0x67)
button 18 'S' (0x53) button 38 'h' (0x68)
button 19 'T' (0x54) button 39 'i' (0x69)
button 20 'U' (0x55) button 40 'j' (0x6A)

Simple vs Addressable

The simple method of control button emulation is to send any one of the control button
characters through the serial port to the VRAM. The disadvantage to this method is that
every device hooked into the VRAM will also hear the command. If any of the other
devices have been programmed with this particular character, they will also respond.

To avoid this problem, the VRAM allows addressable control button emulation. By
using the control-button-emulation command, on page 12, control button commands are
sent directly to a specific device.

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3

Advanced Control

The Advanced Control command set includes more powerful commands to allow more
flexible control of the Advantage VRAM. Unlike Control Button Emulation (which is
basically a one-way control mechanism) advanced control commands allow the VRAM
to return information through the serial port,. The following list summarizes the
commands available using Advanced Control, including the ASCII command character
associated with each command:

! store-as-preset
(save settings as preset)
" retrieve-preset
(put Advantage VRAM into preset mode)
# read-device-settings
(read current settings from device memory)
$ write-settings
(write to device memory)
& addressable-control-button-emulation
(execute control buttons)
( bitwise-operator
(perform bitwise operations on memory locations)
) increment-decrement-memory
(change memory location value by plus or minus one)
* polling-status
(request status update of various functions)
+ sleep-for-10-seconds
(sleep for 10 seconds, ignoring all communication)
, read-eeprom-locations
(read from non-volatile memory)

- write-eeprom-locations1
(write to non-volatile memory)
. set-baud1
(set communications speed)
/ get-version
(retrieve the model information and firmware version date)

Each Advanced Control command requires at least two parameter bytes (four pseudo-hex
characters) to be sent prior to the command character. Each command will be explained
in detail on the following pages.

Some of the commands cause the Advantage VRAM to return information through the
serial port. For each string of information returned to the serial port, the Advantage
VRAM terminates the string by transmitting the ASCII carriage return character (0x0D ­represented in this document as ↵ ).

1

Not recommended, but available for use

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As mentioned earlier, the Advantage VRAM will echo all characters it receives,
regardless of whether or not the characters are valid commands or parameters.
Characters greater than 0x7F are reserved and should not be transmitted to the serial port.
The Advantage VRAM utilizes a subset of the standard ASCII character set. The
following characters have meaning to the Advantage VRAM:

character hexadecimal operation

ASCII control characters (0x00 - 0x1F) no operation
ASCII SPACE character

! thru /
0 thru ?

@
A
B thru `

a
b thru j

k thru z

{ thru DEL

0x80 thru 0xFF (0x80 - 0xFF) RESERVED

(0x20) no operation
(0x21 - 0x2F) Advanced Control commands
(0x30 - 0x3F) pseudo-hex parameters for Advanced

Control commands
(0x40) Control Button Emulation Repeat Code
(0x41) no operation

(0x42 - 0x60) Control Button Emulation commands

(buttons 01 - 31)
(0x61) no operation

(0x62 - 0x6A) Control Button Emulation commands

(buttons 32 - 40)

(0x6B - 0x7A) Control Button Emulation Device Select

Prefix commands

(0x7B - 0x7F) no operation

Device Type Bitmask, Device Number Bitmask, and Device Model Bitmask

In a system which has more than one Advantage product connected together, the Device
Type Bitmask and Device Number Bitmask command parameters provide a mechanism
to individually address a particular device (or a combination of devices). Every
command in the Advanced Control command set requires that a Device Type Bitmask
and a Device Number Bitmask be transmitted as the last two parameter bytes before
transmitting the command character itself. These two bitmask parameters bytes provide a
device addressing capability to specify which of the devices in the system should execute
the command. All devices which are not specifically addressed by these two bitmask
values will ignore the command.

The Device Type Bitmask parameter byte supports up to eight distinct device types - one
bit per device type. The eight device types are:

0x01 [hex] (bit 0) Biamp Advantage DRC 4+4 digital remote control
0x02 [hex] (bit 1) Biamp Advantage EQ28X digitally-controlled graphicEQ
0x04 [hex] (bit 2) Biamp Advantage SPM522D stereo preamp/mixer
0x08 [hex] (bit 3) Biamp Advantage PMX84 programmable matrix switch
0x10 [hex] (bit 4) (reserved for future product)
0x20 [hex] (bit 5) (reserved for future product)
0x40 [hex] (bit 6) (reserved for future product)
0x80 [hex] (bit 7) Advanced Products, such as the Biamp Advantage VRAM

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The Advantage VRAM will only respond to Advanced Control commands if bit 7 of the
Device Type Bitmask parameter byte is a '1'. A command may be directed to more than
one device type in the system by setting all of the corresponding bits in the Device Type
Bitmask to '1's. If only advanced equipment is being addressed (EQ2828/8 DRI, MSP,
and DDL12) 80 is the only bitmask required to use.

The Device Number Bitmask parameter byte supports up to sixty-four distinct device
numbers:

0x00 [hex] Select Device Number 0

0x01 [hex] Select Device Number 1
0x02 [hex] Select Device Number 2
0xFF [hex] Select Device Number 63

A particular Advantage VRAM will only respond to Advanced Control commands if the
Device Number Bitmask parameter byte corresponds to its own device number.

For instance, the bitmask 8007 serves to talk only to advanced product (80) number 7 (07).

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! store-as-preset

Description:

The Advantage VRAM and Advantage VRAMeq each allow up to 17 different presets.
Using the store-as-preset command, the user is allowed to store the current settings
(device configurations) under a specified preset.

Syntax of Command:

pp80dd!

where

pp = Preset number

(0 to 16d; 00 to 10 [pseudo-hex])

80 = Device type bitmask for Advantage Advantage VRAM

dd = Device number bitmask

(1 to 63d; 00 to 3? [pseudo-hex])

! = store-as-preset command character

Syntax of response:

Example:

no response

command: response:
0?8002! (none)

This example causes the Advantage VRAM , device number 2, to store the current
settings under preset number 15d (0? [pseudo-hex]).

Comments:

While there are 16 designated presets on the main control screen in BiampWin, it is also
possible to access and write to the power-up preset, 00. This preset is used by the
VRAM at power-up to load its startup configuration.

However, the current settings at power-down are normally saved to this preset. Consult
the user’s manual (regarding BiampWin) if you wish to disable saving of current settings
at power-down.

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" retrieve-preset

Description:

The retrieve-preset command configures the Advantage VRAM and Advantage
VRAMeq according to a preset definition in non-volatile memory. The user can retrieve
any of the 17 available presets.

Syntax of Command:

pp80dd"

where

pp = Preset number

(1 to 16d; 00 to 10 [pseudo-hex])
80 = Device type bitmask
dd = Device number bitmask
(1 to 63d; to 3? [pseudo-hex])
" = retrieve-preset command character

Syntax of response:

Example:

no response

command: response:

108003! (none)

This example configures the Advantage VRAM , device number 3, according to the
settings stored in preset number 16d (10 [psuedo-hex].

Comments:

Depending on how the VRAM is configured from BiampWin, recalling preset 0 will
either recall the default power-up configuration or recall the state of the VRAM at the
last power-down. Please consult the BiampWin user’s manual for more information

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