Alesis ADAT-M20 RS422 User Manual

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ALESIS M20

RS-422

Implementation

Second Revision

August 5, 1999

INTRODUCTION

This document contains information outlining the implementation of the Sony 9-PinProtocol in the Alesis M20. This is not an official Sony9-pinprotocol document and should not be viewed as such. It is for reference purposes only. To obtain official Sony 9- pin protocol documents, contact Sony directly.

INTERFACE SYSTEM OVERVIEW

Conforming to EIA RS-422A

Four-wirecommunications channel is utilized

Data is transmitted asynchronously, bit serial, word serial with data transmissions between devices being digital

Standard transmission rate on the interface bus is 38.4 kilobits per second (kb/s)

The data utilized by the interface system shall be as follows:

1 START Bit + 8 DATA Bits + 1 PARITY Bit + 1 STOP Bit

MARK

START

D0

D1

D2

D3

D4

D5

D6

D7

PARITY

STOP

BIT

(LSB)

 

 

 

 

 

 

(MSB)

(ODD)

BIT

SPACE

Odd Parity means that the sum of D0 + D1 + … + D7 + PARITY equals an odd number.

Alesis M20 RS-422Document ……………………………….........………………………………Page 2

COMMAND BLOCK FORMAT

The definition of CONTROLLER and DEVICE throughout this document shall be as follows: “CONTROLLER” refers to the unit which controls the VTR.

“DEVICE” refers to the unit (VTR) which is controlled.

The communication between the CONTROLLER and DEVICE is composed of the following:

 

MSD

LSD

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cmd 1

Count

 

 

Cmd 2

 

 

Data -1

 

 

 

 

 

 

 

 

 

Data-n

 

Checksum

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(n = max 15)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 Byte

 

 

 

 

1 Byte

 

 

 

 

1 Byte

 

 

 

 

 

 

 

 

 

 

 

1 Byte

 

 

 

 

1 Byte

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

When the Data Count is zero, theData is not transmitted. When it is not zero, theData corresponding to the value is inserted betweenCmd 2 andChecksum.

Cmd 1

Cmd 1 classifies the COMMAND into main groups which indicate the Function and Direction of the data to follow.

CMD 1

FUNCTION

 

 

 

DIRECTION

 

 

 

 

 

 

CONTROLLER

DEVICE

 

 

 

 

 

 

 

 

 

 

0

System Control

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

System Control Return

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

Transport Control

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4

Preset & Select Control

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6

Sense Request

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7

Sense Return

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data Count

Data Count indicates the number of data bytes added following Cmd 2. It ranges from 0 to F.

Cmd 2

Cmd 2 is the designated COMMAND sent to the DEVICE or returned from the DEVICE.

Data

The number of data bytes and the content is defined by the specific Cmd 2.

Checksum

The Checksum is the sum of all bytes in the message, from Cmd 1/Data Count to the last byte before the Checksum. The Checksum is used to verify data accuracy and reject communication sequences that contain bit errors.

Alesis M20 RS-422Document ……………………………….........………………………………Page 3

CONNECTOR PIN ASSIGNMENT

The interface connector is a 9-pinD-subminiaturefemale connector. The pin assignment for the CONTROLLER and DEVICE is as shown in the following table:

PIN

CONTROLLER

DEVICE

1

Ground

Ground

2

Receive A

Transmit A

3

Transmit B

Receive B

4

Transmit Common

Receive Common

5

Spare

Spare

6

Receive Common

Transmit Common

7

Receive B

Transmit B

8

Transmit A

Receive A

9

Ground

Ground

COMMUNICATION PROTOCOL

All communication between CONTROLLER and DEVICE are under the direct supervision of the CONTROLLER.

The CONTROLLER shall not transmit additional Command Blocks to the DEVICE prior to receiving an appropriate response to the previous Command Block.

The CONTROLLER shall not interrupt transmission of a byte in a Command Block for more than 10 milliseconds. A DEVICE detecting the interruption of a byte in a Command Block that exceeds 10 ms shall execute a Time-Outerror sequence. A DEVICE shall void the receiving Command Block and transmit a NAK(Time-Out).

The DEVICE, following the receipt of a Command Block from the CONTROLLER shall transmit a response within 9 milliseconds.

The DEVICE, upon detection of an error, shall immediately transmit a NAK to the CONTROLLER, with the appropriate error code. The CONTROLLER, upon receipt of the NAK, shall immediately stop transmission of the Command Block

The M20 is a DEVICE (i.e. it only responds to and does not generate Sony 9-Pincommands). In general, the M20 responds to commands in the following manner:

1)Recognized/supported command:

Return an ACK as response to command not requiring data.

Return appropriate data requested.

2)Checksum mis-match:

Return a NAK (with data=checksum error) and take no action.

3)Unrecognized/unsupported command:

Return a NAK (with data=undefined error) and take no action.

4)Number of data bytes is less than expected (e.g. Data byte count < # of bytes needed)

Return a NAK (with data=undefined error) and take no action.

5)If more than 10 milliseconds lapses between bytes in a command block:

Return a NAK (with data=timeout error) and take no action.

Alesis M20 RS-422Document ……………………………….........………………………………Page 4

COMMAND/RESPONSE CHART

The marks shown in the tables mean the following:

O” “*

X

indicates that response to this command is supported; returns appropriate response

indicates that the appropriate status bits are set, but the M20 does nothing; returns an ACK (10.01)

indicates that this command is not supported; returns a NAK Undefined (11.12.01)

 

COMMAND

M20 RESPONSE

 

 

 

00.0C

Local Disable

O

00.1D

Local Enable

O

00.11

Device Type Request

O

 

 

 

01.80

Memory Area Number Preset

X

00.81

Memory Area Number Sense

X

04.82

Memory Area Length Preset

X

00.83

Memory Area Length Sense

X

01.84

Memory Area Select

X

00.85

Memory Area Select Sense

X

01.86

Mem Area Output Select

X

00.87

Mem Area Output Select Sense

X

 

 

 

20.00

Stop

O

20.01

Play

O

20.02

Record

O

20.04

Standby Off

O

20.05

Standby On

O

20.0F

Eject

O

 

 

 

20.10

Fast Forward

O

2X.11

Jog Fwd

O

2X.12

Var Fwd

O

2X.13

Shuttle Fwd

O

 

 

 

20.20

Rewind

O

2X.21

Jog Rev

O

2X.22

Var Rev

O

2X.23

Shuttle Rev

O

Alesis M20 RS-422Document ……………………………….........………………………………Page 5

 

COMMAND

M20 RESPONSE

 

 

 

20.30

Preroll

O

24.31

Cue With Data

O

2X.37

Chase

O

21.38

Prog Speed +

O

21.39

Prog Speed -

O

 

 

 

20.40

Preview

O

20.41

Review

O

20.42

Auto Edit

O

 

 

 

20.54

Anti-ClogTimer Disable

O

20.55

Anti-ClogTimer Enable

O

 

 

 

20.60

Full EE Off

O

20.61

Full EE On

O

20.63

Select EE On

O

20.64

Edit Off

O

20.65

Edit On

O

20.6A Freeze Off

20.6B Freeze On

*

*

20.80

Memory Stop

X

20.81

Memory Play

X

20.82

Memory Write Start

X

 

 

 

20.93

Memory Read Fwd

X

22.A3

Memory Red Rev

X

26.B1

Memory Rd-PointerPreset

X

 

 

 

44.00

Timer-1Preset

X

44.04

TimeCode Gen Preset

O

44.05

TimeCode Gen UBit Preset

O

40.08

Timer-1Reset

O

 

 

 

40.10

In Entry

O

40.11

Out Entry

O

40.12

A In Entry

O

40.13

A Out Entry

O

44.14

In Data Preset

O

44.15

Out Data Preset

O

Alesis M20 RS-422Document ……………………………….........………………………………Page 6

 

COMMAND

M20 RESPONSE

 

 

 

40.16

A In Entry Preset

O

40.17

A Out Entry Preset

O

40.18

In Shift +

O

40.19

In Shift -

O

40.1A

Out +Shift

O

40.1B

Out -Shift

O

40.1C

A In +Shift

O

40.1D

A In -Shift

O

40.1E

A Out +Shift

O

40.1F

A Out -Shift

O

 

 

 

40.20

In Flag Reset

O

40.21

Out Flag Reset

O

40.22

A In Flag Reset

O

40.23

A Out Flag Reset

O

40.24

In Recall

O

40.25

Out Recall

O

40.26

A In Recall

O

40.27

A Out Recall

O

40.2D

Lost Lock Reset

*

 

 

 

4x.30

Edit Preset

O

44.31

Preroll Duration Preset

O

41.32

Tape/Auto Select

X

41.33

Servo Reference Select

X

4x.34

Head Select

X

41.35

Color Frame Select

X

41.36

Timer Mode Select

O

41.37

Input Check

X

44.3C

Postroll Duration Preset

O

 

 

 

40.40

Auto Mode Off

O

40.41

Auto Mode On

O

 

 

 

40.42

Spot Erase Off

X

40.43

Spot Erase On

X

 

 

 

40.48

Video Reference Disable Off

X

40.49

Video Reference Disable On

X

 

 

 

42.50

DA Input Select

X

42.51

DA Sys Emph Select

X

41.58

DA Sys Fs Select

X

 

 

 

45.78

Chase Offset

O

Alesis M20 RS-422Document ……………………………….........………………………………Page 7

 

COMMAND

M20 RESPONSE

 

 

4X.A0 Audio Input Level

X

4X.A1 Audio Output Level

X

 

 

 

61.0A

TC Gen Data Sense

O

61.0C

Current Time Sense

O

 

 

 

60.10

In Data Sense

O

60.11

Out Data Sense

O

60.12

A In Data Sense

O

60.13

A Out Data Sense

O

 

 

 

61.20

Status Sense

O

62.23

Signal Cont Data Sense

X

61.2A

HM Data Sense

X

 

 

 

61.30

Edit Preset Sense

O

60.31

Preroll Duration Sense

O

60.33

Servo Reference Select Sense

X

60.36

Timer Mode Sense

O

60.3C

Postroll Duration Sense

O

 

 

 

60.50

DA Input Sense

X

60.51

DA Sys Emph Sense

X

60.52

DA Input Emph Sense

X

60.53

DA PB Emph Sense

X

60.58

DA Sys Fs Sense

O

 

 

 

61.78

Chase Offset Sense

O

Alesis M20 RS-422Document ……………………………….........………………………………Page 8

M20 COMMAND RESPONSE DETAIL

M20 Responses

10.01 ACK

-Sent in response to receiving a valid command that does not require data.

12.11 Device Type Return

-Sent as response to Device Type Request command.

-The M20 responds as a Sony BVW-75:2x 25

where x is TC frame rate: 0=29.97 or 30, 1=25, 2=24

11.12 NAK

-Sent when detecting communication errors or as response to receiving an undefined command.

-Data Format:

BIT7

BIT6

BIT5

BIT4

BIT3

BIT2

 

BIT1

BIT0

TIME OUT

FRAMING

OVERRUN

PARITY

 

 

 

CHECKSUM

 

 

 

UNDEFINED

ERROR

ERROR

ERROR

 

 

 

ERROR

 

 

 

COMMAND

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SYSTEM CONTROL

00.0C Local Disable

Action: Put M20 into Remote Only Mode(ONLINE CTRL: Remote)

00.1D Local Enable

Action: Put M20 into Local/Remote Mode(ONLINE CTRL: Local/Rem)

00.11Device Type Request

Action: None

Response: Device Type = 12.11 Data = 2x yy

x is the TC frame rate: 0=30 frm, 1=25 frm, 2=24 frmyy is the device id: 25h =BVW-75

Alesis M20 RS-422Document ……………………………….........………………………………Page 9

TRANSPORT CONTROL

• Chase mode is automatically cancelled by all "2x" commands, except 2x.37, 20.60, 20.61, 20.63, 20.64, and 20.65.

20.00Stop

Action: Stop the tape

20.01Play

Action: Play the tape

20.02Record

Action: Record(Punch-InOnly) from any state. Any other transport command, except Eject and Standby Off, will cause a record exit.

20.03Standby Off

Action: If already in standby, then unthread the tape (stop in mode1) If not in standby, then do nothing (just send ACK)

20.04Standby On

Action: Pause the tape (stop in mode2)

Standby = Stopped with the tape threaded.

20.0F Eject

Action: Eject the tape.

If recording, do nothing (just send NAK data=undefined)

20.10Fast Forward

Action: Forward the tape

2X.11

Jog Forward

 

2X.12

Var Forward

 

2X.13

Shuttle Forward

 

 

Data:

DATA-1= N = Coarse speed variable

(required)

 

 

DATA-2= N’ = Fine speed variable

(optional)

 

Action:

Estimate speed closest to M20 capabilities.

20.20Rewind

Action: Rewind the tape (threaded or unthreaded)

2X.21

Jog Rewind

 

2X.22

Var Rewind

 

2X.23

Shuttle Rewind

 

 

Data:

DATA-1= N = Coarse speed variable

(required)

 

 

DATA-2= N’ = Fine speed variable

(optional)

 

Action:

Estimate speed closest to M20 capabilities.

When only DATA-1(N) is given,

Tape Speed = 10((N/32)-2)

When both DATA-1(N) andDATA-2(N’) are given, Tape Speed =10((N/32)-2) +(N’/256)(10(N-(1/32)-2) -

10((N/32)-2))

Alesis M20 RS-422Document ……………………………….........………………………………Page 10