XTA Crossover Control

At the bottom of this document is the spec, from XTA, for the serial protocol that the DP22[46] use. Unfortunately, it's a little incomplete.

Firstly, when a command says that the channel number is `not used' then you don't even send it. Secondly, the crossover requires a straight serial cable (not null-modem) and the baud etc is set via the menu control on the front. The default seems to be 38400, 8N1.

Command 60 returns a frame in the same format as the command format given below except that the first byte is 0xa8. The channel byte isn't sent and the data consists of 8 bytes of level - one for each channel (1 to 6, A and B).

Update:

XTA Application Note # 108

Retrieving mute status from a DP224 / DP226 via RS232/485

Units: DP224, DP226

Using command 50 to upload data from units.

Structure: [Hd][CntH][CntL]

Hd = f0h (No Acknowledge)
CntL = 8 (message length-1) CntH = 0
dev = 98 (DP226), 96 (DP224)
unit =  1 to 32
format = 0
cmd = 50
chan = 0
check=Checksum = sum of all bytes AND 7fh

DP226 returns 235 bytes with Mute status in byte number 42

DP224 returns 169 bytes with Mute status in byte number 32

Mute Status Byte [00fedcba]
       Bit (a) = Output 1 mute Status (1=Mute, 0=Unmute)
       Bit (b) = Output 2 mute Status (1=Mute, 0=Unmute)
       Etc.

Example Commands:
Upload Data from DP224 with unit ID 1
       [f0][00][08][60][01][00][32][00][0d]

Upload Data from DP226 with unit ID 5
       [f0][00][08][62][05][00][32][00][13]

The following is XTA's own protocol documentation...

DP226 & DP224 Remote Protocol

31^st January 2000

Introduction

Both the DP226 and DP224 can be remotely controlled via the MIDI, RS232 or RS485 interfaces. The MIDI interface is an input only connection and can therefore not return any information from the units. The RS232 and RS485 interfaces allow full bi-directional control. Although only the RS485 interface allows multiple units to be controlled simultaneously, it is possible to communicate with a single device via the MIDI or RS232 interfaces and get this unit to relay all commands to its RS485 interface from which the other units may be connected.

Note: f0h refers to hexadecimal notation (f0h=240)

There are two different message structures one for MIDI that uses the system exclusive command and one for RS232 and RS485.

MIDI Structure [SYSEX][7fh][1bh][35h]<device><unit><format><cmd><chan><data>.................[E0X]

RS232/485 structure [Head][CntH][CntL]<device><unit><format><cmd><chan><data>.................[Chk]

• Head= f0h(No Acknowledge) or f1h(Acknowledge. Unit returns single Byte a0h)
• CntL,CntH=message length-1 (CntL = length-1 MOD 128) (CntH =length 1 /128)
• Chk=Checksum = sum of all bytes AND 7fh
• (Note only Head byte has bit 7 set)
• device=98 (DP226) or 96 (DP224)
• unit = Unit ID 1 to 32 (0= all units)
• format=0
• cmd = (0 - 60)

Data Formats

[1] Delay

= 3 bytes (0000xxxx), (0yyyyyyy), (0zzzzzzz)

Delay in 2.6uS steps = 18bit word = 000000xx,xxyyyyyy, yzzzzzzz.

e.g. Set Output 3 of Unit ID 2 a DP226 to 2.5 milliseconds

MIDI =[f0h] [7fh] [1bh] [35h] [62h] [02h] [00h] [01h] [03h] [00h] [07h] [40h] [f7h]

RS =[f0h] [00h] [0bh] [62h] [02h] [00h] [01h] [03h] [00h] [07h] [40h] [2ah]

[2] Gain

= 2 bytes (0xxxxxxx), (0yyyyyyy) 14bit word=00xxxxxx.xyyyyyyy.

(0-550) = Attenuation in 0.1dB steps. (Below +15.0dB)

e.g. Set Input B of Unit ID 4 a DP224 to +1.8dB.

MIDI =[f0h] [7fh] [1bh] [35h] [60h] [04h] [00h] [02h] [08h] [01h] [04h] [f7h]

RS =[f0h] [00h] [0ah] [60h] [04h] [00h] [02h] [08h] [01h] [04h] [6dh]

[3] Mute

= 2 bytes (00fedcba), (000000hg)

a = Output 1 b=2 etc., g = Input A, h=Input B [0 = Norm,1 = Mute].

e.g. Mute Output 5 of all DP226s.

MIDI =[f0h] [7fh] [1bh] [35h] [62h] [00h] [00h] [03h] [10h] [00h] [f7h]

RS =[f0h] [00h] [09h] [62h] [00h] [00h] [03h] [10h] [00h] [6eh]

[4] Configuration

= 3 bytes (0cbbaaaa),(0000gfed),(0iiioooo)

Configuration = 0000aaaa (0-15) Subformat = 000000bb (0-3)

PrePost = c, 16Peq = d, Abswap = e, AutoLim = f, System Mute = g.

InGangMap = iii, OutGangMap= oooo;

[5] Display

= Displays a (ascii) message on unit screen (note: terminate with a zero)

[6] Highpass Filter

= 2 Bytes (0yyyyyyy),(00ww0zzz)

Freq = (0000000w,wyyyyyyy). (0-511) see frequency table.

Type = (00000zzz) (0-6) (0=12dB Bessel, 1=12dB Butterworth,

2=18dB Bessel, 3=18dB Butterworth,

4=24dB Bessel, 5=24dB Butterworth

6=24dB Linkwitz-Riley).

e.g. Set Output 1s highpass filter of Unit ID 5 a DP224 to 1kHz, 24dB Butterworth.

MIDI =[f0h] [7fh] [1bh] [35h] [60h] [05h] [00h] [06h] [01h] [7ch] [15h] [f7h]

RS =[f0h] [00h] [0ah] [60h] [05h] [00h] [06h] [01h] [7ch] [15h] [77h]

[7] Lowpass Filter

= 2 Bytes (0yyyyyyy),(00ww0zzz)

see Highpass filter

[8-23] PEQ sections

= 4 bytes (0wwwwwww),(000bxxyy),(0zzzzzzz),(0qqqqqqq)

Parametric sections are in a logical order.

Q=0qqqqqqq (0-127) see Q table.

Freq = 0000000y,yzzzzzzz (0-511) see frequency table.

Gain =0000000x,xwwwwwww (0 - 405) see filter gain table.

Bypass = b (0=normal, 1=bypassed)

e.g. Set PEQ 3 of Output 3 on Unit ID 5 a DP226 to 1k89Hz, +2.8dB Q 4.0

MIDI =[f0h] [7fh] [1bh] [35h] [62h] [05h] [00h] [0ah] [03h] [7ah] [02h] [1dh] [3ch] [f7h]

RS =[f0h] [00h] [0ch] [62h] [05h] [00h] [0ah] [03h] [7ah] [02h] [1dh] [3ch] [45h]

[24] Limiter

= 2 Bytes (00wwwwww),(0yyyyyzz)

Level = (00wwwwww) (0-63) dBs below 22dB

Attack = (000yyyyy) (0-20) see attack table

Release = (000000zz) (0-3) see release table

e.g. Set Limiter of Output 4 on Unit ID 1 a DP226 to +16dB, 4mS Attack 32mS Release

MIDI =[f0h] [7fh] [1bh] [35h] [62h] [01h] [00h] [18h] [04h] [08h] [21h] [f7h]

RS =[f0h] [00h] [0ah] [62h] [01h] [00h] [18h] [04h] [08h] [21h] [22h]

[25] Phase

= 1 byte (00fedcba)

a = Output 1, b=2 etc., (0 = Norm,1=Invert.)

e.g. Invert Phase on Outputs 1,2 and3 Unit ID 3 a DP224.

MIDI =[f0h] [7fh] [1bh] [35h] [60h] [03h] [00h] [19h] [07h] [f7h]

RS =[f0h] [00h] [08h] [60h] [03h] [00h] [19h] [07h] [7bh]

[26] Store this A (complete Input data)

= 77 bytes

locn(0-40)[1], mute+In16[1], gains[4], delays[6], gangmap[1], InPeq[64]*.

Locn 0=Current else Memory.

*= (arrange all peq's(8) for Input A then B)

[27] Recall Memory

= 1 byte (0yyyyyyy)

Memory = yyyyyyy (1-40)= Input Memories only 1-40

(65-73)= Input & Output Memories 1-9.

(97-105)=Output Memories Only 1-9.

e.g. Recall Input Memory # 12 to all DP226s

MIDI =[f0h] [7fh] [1bh] [35h] [62h] [00h] [00h] [1ah] [0ch] [f7h]

RS =[f0h] [00h] [08h] [62h] [00h] [00h] [1ah] [0ch] [1fh]

Note: To Globally recall a memory without regard for unit type or ID number, it is possible to use the MIDI Program change Command. This is acceptable via the MIDI or RS interfaces.

Format = [coh] [nnh]

e.g. Recall Input Memory # 15 to all connected devices

MIDI =[c0h] [0fh]

RS =[c0h] [0fh]

[28] Name Memory

= 17 Bytes (1^st = Memory number as above) remainder = name

[30] Erase Memory

= 1 byte (0yyyyyyy)

Memory = yyyyyyy (1-40)= Input Memories only 1-40 {0=All Input Memories}.

(65-73)= Input & Output Memories 1-9 {64=All Memories}.

(97-105)=Output Memories Only 1-9 {96=All Output Memories}.

[31] Store this B (complete Output data)

= 215 bytes

locn(0-40)[1] ,config[2] ,gangmap[1], gains[12], delay[18], mute[1], phase[1] , Output filters+Lims[156]+Lock

Locn 0=Current else Memory.

*= (Arrange Hpf, Lpf, Peq(5),Lim for Out 1 then 2 etc.)

[32] System Mute

= 1 Byte (000000xy)

System Mute = x, Temp Mute=y .

[33] Automatic Time Constants (Limiters)

= 1 Byte

0=Manual Time Constants, 1=Automatic.

[34] Reset Input Parametrics

= 1 Byte

0= Input A only, 1= Inputs A & B.

Frequency table (12-409)

The frequency steps are 1/36 of an octave based at 7.8125 Hz.

To calculate frequency from the table value x: 7.8125 * 2^(x/36)

i.e. 252=1kHz.

The Parametrics have a range of 48 - 408. (19.7Hz - 20k2Hz)

The HPF has a range of 12 - 396. ( < 10Hz (effectively bypassed) 16kHz).

The LPF has a range of 78 409. (35Hz 22kHz (effectively bypassed)).

Q table (0-102)

There are 101 Q values from 128 to 0.40.

To calculate the Q from the table value x : 0.25 * 2^((108-x)/12)

i.e. 60= a Q of 4.0;

Note: a Q of 101 = Low shelf and a Q of 102 =High shelf.

Filter gain table (0 - 405)

For the values 0 to 400 these are 0.1dB steps below +15dB

i.e. 0=+15dB, 20=+13dB, 150=0dB, 400= -25dB.

Value 401= -26dB, 402= -27dB. 405= -30dB.

Attack table (0 - 20)

To calculate the Attack time from the table value x : 0.25 * 2^(x/2)

i.e. 7=2.83mS.

Release table (0 - 3)

0= Attack x 4, 1= Attack x 8, 2= Attack x 16, 3= Attack x 32, 4= Attack x 2.