Preliminary and proprietary Information of YAMAR Electronics Ltd. Subject to change without notice.

© 2010 Yamar Electronics Ltd.

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DS-SIG61 R0.932

Figure 4.1 - Write command

Command type 2: Read command.

The Read command, initiated by the Master, requests the status of the SIG61 input pins.

The Read command from the master consists of 3 bytes: sync break, sync field and identifier. The

identifier of this command begins with the four-bit ID of the device, followed by “01”, and finally 2

protection bits. The two protection bits are calculated as described above.

If header detection is correct (including protection bits), the SIG61 device (whose ID matches the one in

the command) shall respond by sending two bytes. A data byte containing the status of its eight input

Signal pins followed by a checksum byte. The checksum calculation is carried out as in the description

above while part of it, the identifier byte, was transmitted by the Master. Figure 4.2 shows a generic

Read command.

Figure 4.2 - Read command

Command type 3: Read-change

The Read-change command is similar to the Read command. However, it enables to detect any change

in the input pins (pulse-like behavior) that may have occurred between two consecutive Read or Read-

change commands. The command from the master instructs the SIG61 to send back information on

changes of its input pins since the last Read or Read-change command. The first change on the pin

after the Read command sets its bit value.

Figure 4.3 shows the process of determining the sent bit value of an input pin.

Figure 4.3 - Determining the recent changed value of an input pin

The Read-change command from the master has 3 bytes: sync break, sync field and identifier.

The identifier begins with the destination device four-bit ID, followed by 10 and terminating with 2

protection bits. The response for this command is a data byte containing the SIG61`s input pins recent

changed value, followed by the checksum byte. See checksum and protection bits calculation

description above. Figure 4.4 shows a Read-changes command.

Read -change

command

1 bit

Input pin level

Sent value

Sync break

Sync Field

P1, P0, 0, 0, Address

Data (8 input bits)

Checksum

Master

Slave

Sync break

Sync Field

P1, P0, 0, 1, Address

Out [7:0]

Checksum

SIG61 Outputs at receiving device

3 bit delay

Transmitted command

Change

“1”

“1”

“0”

“0”