Studer D 732 Service Manual 3

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STUDER D732 RS232
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t) t,.. H <,. ..1.

Level 0: SSCA FCH [Synch (1), Bus busy (1), Read (1), with MSG (1), addr = 12]
Level 1: HB 20h [Send status (010), 12 Bytes status)
Level 2: C 40h [Status 1, reler to table 4.4.1]

04h [Device mode. reter to table 4.4.1 (Auto pause on)]
08h [Track No.]

01 h [Index No.)

28h [Elapsed dlsc time, 43 min]

24h [Elapsed disc time, 36 5]

03h [Elapsed disc time, 03 frames]

03h (Elapsed track time, 03 min]

OFh [Elapsed track time. 15 s]

481 [Elapsed track time, 72 trames]
(Eh [Nominal status = player _play]

01h [Active player command = power_on]

Comment: The master command is 3 bytes long. The MSCA table below shows that this was a
'Read from slave" command with the selected device address sem from the master.

Bits 7 6 5 4 3 0
Control mode Synch (1) Bus busy Read (1) Msg (1) Address

(1) tree (0) Write (0) NoMsg (0)
Slave polling 1 1 1 0 Slave address
Write to slave 1 0 0 1 Slave address
Read from slave 1 1 1 1 Slave address
Bus tree 1 O 0 0 Address 0

The second byte (level 1) contains the message type (001 = Send status request)
and the count of controls (1) transmitted in this message.

The third byte (level 2) contains the message. In this examle it's also only one
command, Status_1 (40h).

The Message_string sent by the slave also starts with the SCA byte (SSCA).

Blts 7 6 5 4 3 0
Control mode Synch Bus Ft/W MINM Address

Slave online 1 1 1 0 Slave address
Slave send Msg 1 1 1 1 Slave address

This SSCA tells the master that the slave specified by the address will send a
message.

The second byte (level 1) contains the message type (010 = Send status) and the
count of controls (12 bytes) to be transmitted in this message.

The lollowing bytes (level 2) contain the message (12 bytes). In this example the
slave sends its Status_1 back to the master.

EDITION: 07/07/94 E4/1 1

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RS232

4.5 Examples

4.5.1 Example 1

STUDER D73

As it can be seen in section 4.2, the R5232 Interface consists of 3 software levels.
This means that the level 0 (SCA - Synch, Control and Address bytes) has to be
transmitted first. When the master sends an SCA this is called a Master SCA. This
byte is used to tell the connected device what the master will do on the bus. For
transmission of the slave it is called SSCA. The SCA byte is the first byte sent from
any device at the beginning of any communication. The slave cannot talk from itself -
it has either to be asked tor a status or to be polled from the master.

Player No. 5 is to be started (Play).

Level 0: MSCA 95h [Synch (1), Bus tree (0), Write (0), with Msg (1 ), eddr. = 5]
Level 1: HB 02h [Send control (000), 1 Byte control]
Level 2: C 16h [Play. according to table in section 4.3.1]
00h [no parameters. according to table in section 4.3.1]
Comment: The command is only 4 bytes long. The MSCA table below shows that this was a
'Write to slave' command with the selected device address sent from the master.
Bite 7 6 5 4 3 0
Control mode Synch (1) Bus busy Read (1) Msg (1) Address
(1) free (0) Write (0) NoMsg (0)
Slave polling 1 1 1 0 Slave address
Write to slave 1 O O 1 Slave address
Read from slave 1 1 1 1 Slave address
Bus tree 1 o 0 0 Address 0
The second byte (level 1) contains the message type (000 = Send control) and the
count of controls (2) to be transmitted in this message.
The third byte (level 2) contains the message. In this example it is the Play command
with no parameters - according to the table in section 4.3.1: 16h, 00h.
4.5.2 Example 2
Player No. 12 has to transmit the elapsed time of the momentarily played track.
The master has to ask the slave for a specific status. The slave transmits the required
message back to the master.
Level 0: MSCA FCh [Synch (1). Bus busy (1). Read (1), with MSG (1 ), eddr = 12]
Level 1: HB 11h [Send status request (001 ), 1 Byte control]
Level 2: C 40h [Send_status 1. rater to table 4.4.1]

After having received this command the slave device sends its status to the master.
In this case the first byte is called SSCA. In the SCA the slave only can change the
Msg/NoMsg bit in case of sending or not sending messages. So the remainder of the
SCA sem by the master (MSCA) is still the same in the SSCA byte.

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EDITION: 07/07/94